EPA910/R-96-006
r/EPA
United States
Environmental Protection
Agency
Region 10
1200 Sixth Avenue
Seattle WA 98101
Alaska
Idaho
Oregon
Washington
Alaska Operations Office
September 1996
Functional Profile of
Black Spruce Wetlands in
Alaska
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FUNCTIONAL PROFILE OF
BLACK SPRUCE WETLANDS
IN ALASKA
Prepared for
U.S. Environmental Protection Agency
Region 10
Prepared by
Roger A. Post
Alaska Department of Fish and Game
Fairbanks, Alaska
1996
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FUNCTIONAL PROFILE OF
BLACK SPRUCE WETLANDS IN ALASKA
by
Roger A. Post,
Alaska Department of Fish and Game
©1996 Alaska Department of Fish and Game
FUNDING
Funding for this report was provided by the U.S. Environmental Protection
Agency pursuant to Section 104(b)(3) of the Clean Water Act and by the
Alaska Department of Fish and Game using state-appropriated General Funds.
DEDICATION
This profile is dedicated to Dr. Maurice M. Alexander, Professor Emeritus,
State University of New York, College of Environmental Science and Forestry
at Syracuse. Dr. Alexander found room for "one more grad student" in his De-
partment of Forest Zoology and through a teaching assistantship for his field
ecology course exposed that student to the cattails of Clay Marsh, bulrushes
of the inlet delta at Jamesville Reservoir, and hemlock swamps of the Heiberg
Forest. Perhaps that exposure to wetlands needed a decade or two of incuba-
tion before recently surfacing in my career, but I am extremely grateful that
it did, thanks in no small part to Dr. Alexander.
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PREFACE
The functions and values of Alaska's wide vari-
ety of wetlands have received little study. This lack
of information has posed difficulties for wetlands
regulation pursuant to Section 404 of the federal
Clean Water Act. The U.S. Environmental Protection
Agency (EPA) and the U.S. Army Corps of Engi-
neers (USAGE) must balance the public's interest in
a viable economy against the public's interest in
wetland conservation and protection of water qual-
ity. Knowledge of wetland functions and values is a
necessary component of such balancing in the regu-
latory process.
Alaska wetlands supporting black spruce are
abundant and therefore commonly affected by devel-
opment. These wetlands have been widely perceived
as having low value, but objective documentation of
their functions was lacking. Consequently, the EPA
funded the Alaska Department of Fish and Game
(ADF&G) to comprehensively review available lit-
erature and prepare a community profile for black
spruce wetlands in Alaska. The ADF&G proposed,
and EPA accepted, organizing the profile around
commonly accepted wetland functions to maximize
usefulness to wetland regulators and the regulated
community.
Our initial expectations were that we would find
little applicable literature and the profile would soon
be written. Upon conducting our initial review, how-
ever, we discovered that a fair number of boreal for-
est studies and studies addressing treed bogs and
fens existed in the literature. The ADF&G contrib-
uted substantial resources beyond the original grant
matching funds to this project in order to produce a
comprehensive treatment of black spruce wetlands.
This process has taken more time than intended, but
we believe the profile benefited from its long gesta-
tion.
The USAGE, Natural Resources Conservation
Service, and State of Alaska currently are develop-
ing models for use in the Hydrogeomorphic (HGM)
approach to wetland assessment. Functional profiles
of various wetland classes are an integral part of this
approach. We hope that this profile will advance de-
velopment of HGM for Alaska and benefit Alaskans
for years to come.
in
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m
Functional Profile of Black Spruce Wetlands in Alaska
CONTENTS
DEDICATION ii
PREFACE iii
CONTENTS iv
PHOTOGRAPHS viii
FIGURES ix
TABLES x
ACKNOWLEDGEMENTS xiii
PHOTOGRAPHS xiv
INTRODUCTION 1
BLACK SPRUCE AND THE TAIGA ENVIRONMENT 4
CLIMATE 4
Temperature and Precipitation 4
Evapotranspiration 4
Solar Radiation 6
PERMAFROST 7
Distribution 7
Formation and Degradation 7
Geomorphic Features 9
Effect on Soil Moisture 10
TAIGA ECOSYSTEMS 10
Paleoecology 10
Zones of Taiga Vegetation 10
Black Spruce Communities 12
Ecologic Succession 12
Succession-Permafrost Relationships 14
BLACK SPRUCE SPECIES CHARACTERISTICS 15
Distribution 15
Growth Forms and Densities 15
Adaptations 16
Reproduction 17
iv
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Contents
BLACK SPRUCE WETLANDS 18
WHAT IS A WETLAND? 18
Definitions and Defining Characteristics 18
Mires 20
Relationship of Black Spruce Wetlands to Mires 27
VEGETATION 22
Wetland Classes and Forms Supporting Black Spruce 22
Wetland Potential of Representative Black Spruce Community Types in Alaska 22
ACTIVITIES POTENTIALLY AFFECTING BLACK SPRUCE WETLANDS 24
Placement of Fill 24
Drainage 24
Flooding 24
Clearing and Harvest of Woody Vegetation 25
Disposal of Waste 25
Mining of Peat 25
RESEARCH 26
Forestry Studies 27
Ecologic Studies 27
Physical Studies 27
Current Knowledge 27
HYDROLOGIC FUNCTIONS 29
GROUND WATER DISCHARGE 29
Suprapermafrost Groundwater 29
Subpermafrost Groundwater 30
Groundwater Discharge in Unfrozen Terrain 30
Functional Summary 31
Functional Sensitivity to Impacts 31
GROUNDWATER RECHARGE 32
Suprapermafrost Groundwater 32
Subpermafrost Groundwater 33
Groundwater Recharge in Unfrozen Terrain 33
Functional Summary 33
Functional Sensitivity to Impacts 33
FLOW REGULATION 34
Subsurface Storage of Precipitation 34
Detention and Depression Storage of Precipitation 35
Release of Stored Precipitation and Effect on Streamflow 35
Functional Summary 36
Functional Sensitivity to Impacts 37
EROSION CONTROL 38
Thermal Stability in Permafrost Terrain 38
Mechanical Stability 35
Functional Summary 38
Functional Sensitivity to Impacts 35
DATA GAPS 39
Groundwater Discharge 39
Groundwater Recharge 39
Flow Regulation 39
Erosion Control 39
Functional Sensitivity to Impacts 39
WATER QUALITY FUNCTIONS 40
SEDIMENT RETENTION 40
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Functional Profile of Black Spruce Wetlands in Alaska
Suspended Solids in Wetland Runoff 40
Functional Summary 41
Functional Sensitivity to Impacts 42
NUTRIENT UPTAKE 42
Moss Layer 42
Tree, Shrub, and Herb Layers 44
Functional Summary 46
Functional Sensitivity to Impacts 46
NUTRIENT TRANSFORMATION 47
Nitrogen 47
Phosphorus 51
Functional Summary 54
Functional Sensitivity to Impacts 55
CONTAMINANT REMOVAL 55
Metal Uptake and Storage 55
Nutrient Immobilization 56
Buffering Capacity 58
Contaminant Degradation 58
Functional Summary 59
Functional Sensitivity to Impacts 59
DATA GAPS 60
Sediment Retention 60
Nutrient Uptake 60
Nutrient Transformation 60
Contaminant Removal 60
Functional Sensitivity to Impacts 60
GLOBAL BIOGEOCHEMICAL FUNCTIONS 62
CARBON CYCLING AND STORAGE 62
Primary Production 62
Decomposition 63
Functional Summary 65
Functional Sensitivity to Impacts 66
DATA GAPS 66
ECOLOGIC FUNCTIONS 67
NUTRIENT CYCLING 67
Distribution of Nutrients 67.
Cycling Times and Fates of Nutrients 67
Functional Summary 69
Functional Sensitivity to Impacts 69
NUTRIENT EXPORT 69
Nitrogen 70
Phosphorus 70
Paniculate and Dissolved Organic Carbon 71
Functional Summary 73
Functional Sensitivity to Impacts 73
FOOD CHAIN SUPPORT 74
Primary Production 74
Food Chains 76
Functional Summary 78
Functional Sensitivity to Impacts 79
HABITAT 79
Birds 79
Mammals 80
vi
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Contents
Amphibians 81
Functional Summary 772
Functional Sensitivity to Impacts 772
DATA GAPS 113
Nutrient Cycling 773
Nutrient Export 773
Food Chain Support 113
Habitat 113
Functional Sensitivity to Impacts 774
SOCIOECONOMIC USES 115
CONSUMPTIVE 115
Subsistence and Personal Uses 775
Extraction of Economic Resources 776
Use Summary 77$
Use Sensitivity to Impacts 118
NONCONSUMPTIVE 118
Active Recreation 779
Passive Recreation and Use of Heritage Sites 779
Use Summary 720
Use Sensitivity to Impacts 720
DATA GAPS 121
Consumptive Uses 727
Nonconsumptive Uses 727
Use Sensitivity to Impacts 722
SUMMARY AND CONCLUSIONS 123
BLACK SPRUCE AND THE TAIGA ENVIRONMENT 123
BLACK SPRUCE WETLANDS 124
HYDROLOGIC FUNCTIONS 125
WATER QUALITY FUNCTIONS 126
GLOBAL BIOGEOCHEMICAL FUNCTIONS 127
ECOLOGIC FUNCTIONS 128
SOCIOECONOMIC USES 129
CONCLUSIONS 130
LITERATURE CITED 131
APPENDIX A - WETLAND CLASSIFICATION 156
U.S. FISH AND WILDLIFE SERVICE SYSTEM 156
CANADIAN SYSTEM 156
APPENDIX B - SUBARCTIC AND BOREAL BOGS AND FENS IN THE CANADIAN
CLASSIFICATION SYSTEM 158
APPENDIX C - PHYSICAL DESCRIPTIONS OF REPRESENTATIVE BLACK SPRUCE
COMMUNITY TYPES OF ALASKA 161
APPENDIX D - INTERPRETATION OF AVIAN SURVEYS WITH RESPECT TO BLACK
SPRUCE WETLAND HABITATS 163
ALASKA 163
CANADA !63
LOWER 48 STATES 163
GLOSSARY 168
VII
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Functional Profile of Black Spruce Wetlands in Alaska
PHOTOGRAPHS
Photo 1. Aerial view of black spruce/Sphagnum wetland, Eagle Quadrangle, eastern Interior Region viv
Photo 2. Ground-level view of black spruce/Sphagnum wetland, Eagle Quadrangle,
eastern Interior Region xiv
Photo 3. Lowland black spruce wetland in a wetland mosaic, McGrath Quadrangle,
western Interior Region xv
Photo 4. Moderately treed black spruce wetland near Aniak, southwestern Interior Region xv
Photo 5. Upland black spruce wetlands on interfluves, Yukon-Charley Rivers National Preserve,
eastern Interior Region xvi
Photo 6. Black spruce/graminoid tussock wetland, Gulkana Quadrangle, southern Interior Region xvi
Photo 7. Black spruce/cotton grass wetland, Kenai Peninsula, Southern Region xvii
Photo 8. Black spruce/shrub wetland, Talkeetna Quadrangle, Southern Region xvii
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FIGURES
Figure 1. Physical subdivisions of Alaska 2
Figure 2. Distribution of North American taiga 5
Figure 3. Equivalent latitudes for several forest research stands at 65 degrees N latitude 7
Figure 4. Permafrost distribution in Alaska 8
Figure 5. Nutrient uptake by green moss tissue in a permafrost black spruce stand, interior Alaska,
as compared to nutrient addition by precipitation throughfall and litterfall 43
Figure 6. Comparative nutrient requirements for black spruce and other taiga trees as a group
(white spruce, quaking aspen, paper birch, and balsam poplar) 44
Figure 7. Cattail and sedge biomasses at wastewater discharge and control sites, Hay River, N.W.T 46
Figure 8. Concentrations of NH4-N and NO3-N in incubated organic material from a mature black
spruce-lichen woodland, Quebec 50
Figure 9. Net primary production for components of a northern ribbed fen in subarctic Quebec 64
Figure 10. Carbon balance for components of a northern ribbed fen in subarctic Quebec 64
Figure 11. Potassium distribution in a raised bog 68
Figure 12. Phosphorus exports from an organic-substrate cattail marsh, Ontario 71
Figure 13. Humic and fulvic acid concentrations in runoff from Minnesota mires 72
Figure 14. Soil and air temperatures at which maximum photosynthetic rates
occurred in seedlings of taiga hardwoods 75
Figure 15. Annual production of taiga trees near Fairbanks, Alaska 75
Figure 16. Distribution of aboveground arthropod taxa among trophic levels in black spruce
stands of interior Alaska 77
IX
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m
Functional Profile of Black Spruce Wetlands in Alaska
TABLES
Table 1. Representative climatic data for interior Alaska (Fairbanks) 6
Table 2. Permafrost-related geomorphic features of wetlands 9
Table 3. Paleoecologic history of black spruce in interior Alaska 11
Table 4. Paleoecologic history of black spruce in Yukon and western Northwest Territories 11
Table 5. Representative black spruce community types of interior Alaska 13
Table 6. Fire recurrence intervals for North American taiga locations 13
Table 7. Stem densities of several immature and mature black spruce stands, interior Alaska 16
Table 8. Soil pH at several black spruce sites in interior Alaska 16
Table 9. Representative wetland definitions 19
Table 10. Representative characteristics of bogs and fens 20
Table 11. Organic layer thickness and typical soils of Alaska Vegetation Classification (Level IV)
classes dominated by black spruce 21
Table 12. Frequently occurring genera and species in North American bogs and fens 22
Table 13. Inferred probabilities that typical interior Alaska black spruce community types are
jurisdictional wetlands based on stand descriptions from Foote (1983:28-48) 23
Table 14. Water quality variables that have shown increased levels in runoff from ditched or
mined peatlands 26
Table 15. Typical concentrations of total suspended solids (TSS) in runoff from nonpermafrost peatlands 41
Table 16. Comparative N mineralization in several European and North American mires and forest stands 49
Table 17. Pools of NH4-N and NO3-N in wetland and nonwetland Alaska forest stands 50
Table 18. Phosphorus concentrations in several Canadian taiga mires with Fe concentrations
<3.7mgFe-g-' 52
Table 19. Phosphorus concentrations and pools in organic and mineral layers of several taiga
black spruce stands 53
Table 20. Phosphorus-related characteristics of interior Alaska black spruce stands 53
Table 21. Periods of active peat accumulation in several North American and Asian mires 57
Table 22. Soil carbon contents of representative interior Alaska black spruce stands 63
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Tables
Table 23. Combined carbon contents of aboveground tree components and forest floors of
representative interior Alaska black spruce stands based on biomass 63
Table 24. Contrasting turnover times for nutrient elements in nonpermafrost
black spruce stands in Ontario and largely permafrost stands in Alaska 68
Table 25. Nitrogen mineralization and fixation in a Minnesota bog and Alaska black spruce stands 69
Table 26. Nitrogen export in runoff from bogs and tundra peatland 70
Table 27. Phosphorus concentrations in runoff from northern peatlands 70
Table 28. Carbon concentrations in runoff from northern peatlands 72
Table 29. Carbon export rates for swamps and peatlands 73
Table 30. Comparative production of selected wetland communities and community components 76
Table 31. Common soil invertebrates found in European blanket bogs and Alaska tundra 78
Table 32. Use of aquatic habitats potentially associated with black spruce wetlands (BSW)
by waterbirds (loons, grebes, waterfowl, gulls, and terns) in Alaska 82
Table 33. Use of black spruce wetlands (BSW) in Alaska by raptorial birds (hawks, eagles, harriers,
ospreys, falcons, and owls) 86
Table 34. Use of black spruce wetlands (BSW) in Alaska by nonpasserine birds other than
waterbirds and raptors (see preceding tables) 89
Table 35. Use of black spruce wetlands (BSW) in Alaska by passerine birds 94
Table 36. Frequently occurring avian species in Alaskan and Canadian black spruce forests and
wetlands (all waterbirds except gulls, all raptors, and species not occurring in interior
Alaska are excluded) 101
Table 37. Use of black spruce wetlands (BSW) in Alaska by insectivores, chiropterans, rodents, and
lagomorphs 103
Table 38. Use of black spruce wetlands (BSW) in Alaska by carnivores? 107
Table 39. Use of black spruce wetlands (BSW) in Alaska by cervid artiodactyls (moose, caribou) 110
Table 40. Mammals most characteristic of black spruce wetlands in Alaska Ill
Table 41. Wood frog reproduction under ombrotrophic and minerotrophic conditions Ill
Table 42. Representative subsistence harvests for several interior Alaska resources directly or
indirectly related to black spruce wetlands 116
Table 43. Mean annual estimated furbearer harvests between 1986 and 1991 in Game Management
Unit (GMU) 25 (northeastern Interior), GMU 24 (Koyukuk River), and GMU 21
(mid-Yukon River) 117
Table 44. Motorized forms of active recreation that occur in black spruce wetlands (BSWs) in Alaska 119
Table 45. Nonmotorized forms of active recreation that occur in black spruce wetlands
(BSWs) in Alaska 119
Table D-l. Interpretation of avian surveys by Spindler and Kessel (1980) in eastern interior Alaska
with respect to black spruce wetlands 164
Table D-2. Interpretation of breeding bird surveys by Cooper et al. (1991:279-280) near Tok and
Gulkana, Alaska, with respect to black spruce wetlands 164
XI
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Functional Profile of Black Spruce Wetlands in Alaska
Table D-3. Interpretation of breeding bird surveys by Martin et al. (1995) in the Badger Slough
watershed near Fairbanks, Alaska, with respect to black spruce wetlands 165
Table D-4. Interpretation of avian habitat studies by Spindler (1976) on the Fairbanks Wildlife
Management Area with respect to black spruce wetlands 165
Table D-5. Interpretation of avian surveys by Kessel et al. (1982) near the Susitna River, Alaska,
with respect to black spruce wetlands 165
Table D-6. Interpretation of avian survey plots used by Carbyn (1971) in Northwest Territories,
Canada, with respect to black spruce wetlands 166
Table D-7. Interpretation of avian surveys by Gillespie and Kendeigh (1982) in Manitoba, Canada,
with respect to black spruce wetlands 166
Table D-8. Interpretation of descriptions by Erskine (1977) of avian habitat use in boreal Canada 167
Table D-9. Interpretation of avian surveys by Ewert (1982) in Michigan "bogs" with respect to
black spruce wetlands 167
XII
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ACKNOWLEDGEMENTS
Phil North, U.S. Environmental Protection
Agency, Anchorage, has patiently overseen this
project from its inception. Alvin G. Ott, Alaska De-
partment of Fish and Game, Habitat and Restoration
Division, Fairbanks, provided substantial project
funding from his regional budget and also has waited
patiently for the project's completion. M. Torre
Jorgenson, ABR, Inc., Fairbanks; Charles H. Racine,
U.S. Army Cold Regions Research and Engineering
Laboratory, Hanover; and Leslie A. Viereck, U.S.
Forest Service Institute of Northern Forestry, Uni-
versity of Alaska-Fairbanks, provided helpful advice
on profile organization and presentation.
Philip D. Martin, U.S. Fish and Wildlife Service,
Ecological Services, Fairbanks; John Wright, Alaska
Department of Fish and Game, Division of Wildlife
Conservation; Jacqueline D. LaPerriere, Alaska Co-
operative Fish and Wildlife Research Unit, Univer-
sity of Alaska-Fairbanks; Erich H. Follmann, Uni-
versity of Alaska-Fairbanks; and Doug Kane, Uni-
versity of Alaska-Fairbanks, provided constructive
reviews of the one or more chapters of the profile. I
also wish to thank Shelli A. Swanson, U.S. National
Park Service, Fairbanks; John Wright; and Philip
Martin for provision of unpublished data (some now
published) during preparation of this profile.
I am particularly grateful to David K. Swanson,
Natural Resources Conservation Service, Fairbanks;
Stephen C. Zoltai, Canadian Forest Service,
Edmonton; and Paul H. Glaser, University of Minne-
sota, Minneapolis, for exceptionally thorough re-
view of the entire document and provision of in-
sightful comments based on their extensive field ex-
perience and knowledge of peatlands. Finally, James
Lukin, Lukin Publications Management, donated his
time to prepare this profile for publication, for which
I am indebted.
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Functional Profile of Black Spruce Wetlands in Alaska
Photo 1. A.eria.1 view of black 5/?rwce/Sphagnum wetland, Eagle Quadrangle, east-
em Interior Region (photo courtesy U.S. Fish and Wildlife Service).
Photo 2. Ground-level view of black spruce/Sphagnum
wetland, Eagle Quadrangle, eastern Interior Region
(photo courtesy U.S. Fish and Wildlife Service).
xiv
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Photo 3. Lowland black spruce wetland in a wetland mosaic. McGrath Quadrangle,
western Interior Region (photo courtesy U.S. Fish and Wildlife Sen'ice).
Photo 4. Moderately treed black spruce wetland near Aniak, southwestern Interior
Region (photo courtesy U.S. Fish and Wildlife Ser\'ice).
xv
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Functional Profile of Black Spruce Wetlands in Alaska
Photo 5. Upland black spruce wetlands on interfluves, Yukon-Charley Rivers Na-
tional Preserve, eastern Interior Region (photo courtesy U.S. Fish and Wildlife
Service).
Photo 6. (photo courtesy U.S. Fish and Wildlife Service).
xvi
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Photo 7. Black spruce/cotton grass wetland, Kenai Peninsula, Southern Region (photo
courtes\ U.S. Fish and Wildlife Sen-ice).
Photo 8. Black spruce/shrub wetland, Talkeetna Quadrangle, Southern Region
(photo courtesy U.S. Fish and Wildlife Sen-ice).
XVII
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INTRODUCTION
Alaska has 70.7 million ha of wetlands, approxi-
mately 63% of the remaining wetlands in the United
States (Hall et al. 1994). Palustrine scrub-shrub and
forested wetlands (see Appendix A for classification
terminology) contribute about 51.7 million ha to
Alaska's wetland area (Hall et al. 1994). In the Inte-
rior (Figure 1), most of the saturated forested wet-
lands (3.6 million ha) are classified as needle-leaved
(i.e., conifer), and approximately half of the
palustrine scrub-shrub wetlands (21.1 million ha) are
dominated by black spruce (Picea mariana) (Hall et
al. 1994; J. V. Hall, U.S. Fish Wildl. Serv., pers.
commun.). Palustrine scrub-shrub and forested wet-
lands cover about 2.8 million ha of southern Alaska
(Hall et al. 1994), much of which lies outside the
distribution of black spruce. Wetlands supporting
black spruce probably occupy about 14 million ha of
Alaska, mainly in the Interior.
Open black spruce forests and woodlands often
merge with sparsely treed or treeless Sphagnum
peatlands (Viereck and Dymess 1980) because size
and stand density decrease with increasing soil mois-
ture. These peat-accumulating wetlands develop in
poorly drained lowlands and on cold slopes through-
out the boreal forest where resistant bedrock, marine
and lacustrine clays, glacial tills, or permafrost im-
pede drainage (Heilman 1963; Brown and Pewe
1973; Zoltai, Tarnocai et al. 1988). Black spruce/
moss woodlands occurring on peat sometimes are
called "muskeg" (Gabriel and Talbot 1984:74, Natl.
Wetlands Working Group 1988:437), although this
term is imprecise and not generally used in contem-
porary wetland classification systems (Zoltai 1988),
in part because similar communities occur on
nonwetland sites (S. C. Zoltai, Can. For. Serv., pers.
commun.).
Poorly drained black spruce stands occur in the
Closed Needleleaf Forest, Open Needleleaf Forest,
Needleleaf Woodland, Open Dwarf Tree Scrub, and
Dwarf Tree Scrub Woodland hierarchical groupings
of The Alaska Vegetation Classification (Viereck et
al. 1992); scattered black spruce can occur in the
Open Low Scrub grouping, as well. Lugo (1990:2)
considers any wetland with "a significant component
of woody vegetation, regardless of the size of the
plants" as a forested wetland. For purposes of this
report, a wetland (sensu Cowardin et. al. 1979, Natl.
Res. Counc. 1995:59) containing black spruce of any
size or stand density is a black spruce wetland
(BSW).
Black spruce wetlands, by virtue of their abun-
dance, are important boreal ecosystems. This abun-
dance, and the regulated status of wetlands in the
United States, engender conflicts with human eco-
nomic development activities. Many communities in
the Interior are surrounded by BSWs. Although such
wetlands generally are not attractive for low-density
residential development, commercial development,
including high-density housing, may occur follow-
ing wetland drainage or placement of fill. Regulatory
decisions concerning conversion of these wetlands
to other uses pursuant to Section 404 of the federal
Clean Water Act require knowledge about their wet-
land functions (sensu Adamus and Stockwell 1983,
Sather and Smith 1984) and hence their values to
society.
Wetland functions are the physical, chemical, and
biological processes that occur within wetlands.
Such functions may be regarded as ecologic services
provided by wetlands (Larson et al. 1988). These
services are expressed at the level of ecosystem
components (e.g., fish and wildlife populations, tim-
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Functional Profile of Black Spruce Wetlands in Alaska
Western
Figure 1. Physical subdivisions of Alaska {Hall et al, 1994).
her stands), entire ecosystems (e.g., water storage,
primary production), or global life support systems
(e.g., biogeochemical cycling of elements), and hu-
mans may assign values to them (Odum 1979).
Several authors have grouped and described wet-
land functions based on available literature (Adamus
and Stockwell 1983, Sather and Smith 1984). Other
authors have discussed individual functions or
closely related functions, for example hydrology
(Carter et. al. 1979), water quality (Kadlec and
Kadlec 1979), primary production and food chain
support (Livingston and Loucks 1979), and habitat
(Weller 1979). Socioeconomic aspects of wetlands
are often called wetland functions (Sather and Smith
1984:58-68), but socioeconomics involves human
perceptions and activities and thus values. Because
this report does not discuss values, it will identify
only socioeconomic "uses" of wetlands. These uses
depend upon the physical, chemical, and biological
processes, or functions, that shape individual wet-
lands.
Many people perceive few functions and low val-
ues for BSWs. Although hydrologic and ecologic
aspects of BSWs have been studied in Alaska, par-
ticularly in relation to fire, permafrost, and ecologic
succession, systematic examination of wetland func-
tions associated with these communities has not oc-
curred. Impacts of wetland conversion on hydrology,
water quality, nutrient cycling, nutrient export, food
chain support, fish and wildlife habitat, and recre-
ation and heritage uses must be known before wet-
land avoidance, impact minimization, or
compensatory mitigation can rationally be applied
during the regulatory process.
The objective of this report is to provide a "func-
tional profile" of Alaska's BSWs for use by scien-
tists, wetland managers, commercial interests, and
citizens. These groups can use the profile to identify
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Introduction
potential wetland research topics, provide a basis for
regulatory and resource management decisions, de-
sign potential development projects to minimize
impacts to wetland functions, and become informed
participants in wetland conservation. In addition,
functional profiles are an integral part of the
Hydrogeomorphic approach to wetland assessment
(Brinson 1993), a system under development for po-
tential nationwide application by the U.S. Army
Corps of Engineers. This profile should facilitate
implementation of the hydrogeomorphic system in
Alaska.
Because few directed studies of wetland func-
tions exist for Alaska, this profile cites many studies
conducted outside Alaska, usually within the boreal
forest but occasionally including northern temperate
locations. Wetland functions extrapolated from one
area to another are likely to be correct in broad out-
line when reviewed for consistency with research
conducted in the geographic area of interest but
nonetheless should be used with caution. Future re-
search should verify these functions and make clear
the unique details of Alaska's BSWs.
This report first describes the northern coniferous
(boreal) forest biome to establish the context within
which BSWs occur. Descriptive material pertinent to
these communities follows discussion of general
wetland characteristics and classification systems to
provide a vocabulary for the remainder of the pro-
file. Activities potentially impacting BSWs, as well
as research applicable to the functions of these wet-
lands, also are discussed. Finally, the main body of
the profile identifies functions and socioeconomic
uses of BSWs, analyzes their sensitivities to place-
ment of fill and drainage, and identifies data gaps on
a function-by-function basis.
A glossary is appended to the profile. Terms
likely to be unfamiliar to nonspecialists appear in
bold italics when first defined in the text and appear
again in the glossary for ease of reference.
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Functional Profile of Black Spruce Wetlands in Alaska
BLACK SPRUCEAND
THE TAIGA ENVIRONMENT
Black spruce wetlands occur within the taiga, the
northern coniferous forest extending across northern
North America (Figure 2) and Eurasia (Viereck
1975, Pruitt 1978:1-7, Oechel and Lawrence 1985).
Long, cold winters; short, warm summers; relatively
low precipitation; permafrost (in the north); and a
fire-dominated landscape (in the west) are character-
istic of this environment in North America (Viereck
1983, Kimmins and Wein 1986). The following dis-
cussion of climate, permafrost, and plant ecology
demonstrates how the taiga environment establishes
conditions that support black spruce forests and
wetlands.
CLIMATE
Climate, in part, establishes the range of ecosys-
tems that exist in the taiga (Van Cleve et al. 1991).
Subarctic climates characterize this zone, which is a
source region for continental polar air masses
(Strahler 1963:329-344). Maritime influences may
be present in coastal regions at the periphery of the
boreal forest (Zasada 1976; Foster 1984; Wells and
Hirvonen 1988; Zoltai, Tamocai et al. 1988; Zoltai,
Taylor et al. 1988). The following synopsis of cli-
matic factors facilitates understanding ecosystem
processes in taiga wetlands.
Temperature and Precipitation
Temperature extremes exemplify the primarily
continental aspects of the taiga climate (Table 1).
Mean monthly temperatures in Fairbanks, Alaska,
vary much more on an annual basis for winter than
for summer, with extreme low temperatures occa-
sionally reaching -50°C (Bowling 1979,1984). Pre-
cipitation (Table 1) varies from about 250 mm to
more than 500 mm over the range of black spruce in
Alaska (precipitation distributions mapped by
Watson [1959 in Wahrhaftig 1965] and by Lampke
[1979 in Rundquist et al. 1986]). Higher elevations
receive more precipitation than do lowlands
(Haugen et al. 1982, Slaughter and Viereck 1986).
Snowcover is essentially continuous between
November and March or April because thawing con-
ditions rarely occur during this period (Bowling
1979). Taiga snow (api) generally is uniformly dis-
tributed, with annual variation in depth of accumu-
lation, and characterized "by low density (Pruitt
1978:12-14). Several metamorphic processes act to
increase or stratify snow density during the course of
the winter (Marchand 1987:12-19). Pukak or depth
hoar crystals grow in a columnar structure at the base
of the snowpack forming a subnivean space that pro-
vides a favorable microclimate for overwintering
plants and animals (Pruitt 1984).
Evapotrampiration
Evaporation and transpiration, in part, control
soil moisture (Buckman and Brady 1969:240).
Thornthwaite's (1948 in Lee 1980:178) estimator for
potential evapotranspiration (PET) is based on mean
monthly air temperature and approximated by
evaporation from Class A pans (Ford and Bedford
1987). Water balances calculated using PET (Table
1) can be inaccurate (Ford and Bedford 1987), how-
ever, if underlying assumptions are not met
(Buckman and Brady 1969:188-196, Lee 1980:154-
181, Ingram 1983).
The difference between measured precipitation
and runoff provides an alternative estimator of
evapotranspiration that can yield much smaller val-
ues than calculated PET (Lee 1980:170-174, Ford
and Bedford 1987). About half of annual precipita-
4
-------
Black Spruce and the Taiga Environment
Base map by Mountain High Maps™
Copyright © 1993 Digital Wisdom, Inc.
7igure 2. Distribution of North American taiga (Oechel and Lawrence 1985).
5
-------
m
Functional Profile of Black Spruce Wetlands in Alaska
Table 1. Representative climatic data for interior Alaska (Fairbanks).
Climatic Variable (units)
January Mean Temperature (°C)
July Mean Temperature (°C)
Freezing Degree-Days (°C-day)
Thawing Degree-Days (°C-day)
Growing Season (frost-free days [0°C])
Total Precipitation (mm)
Precipitation as Snowfall (%)
Potential Evapotranspiration (mm)
Precipitation Deficit (mm)
December Solar Radiation (kJ-m~2-day"')
June Solar Radiation (kJ-m~2-day~')
Variable Value
-24.4
17.1
3,084
1,799
89 to 90
284
35
350 to 450
188
231
22,375
Source
Haugenetal. (1982:6-8)
Haugenetal. (1982:6-8)
Haugenetal. (1982:6-8)
Haugenetal. (1982:6-8)
Ping (1 987), Sharratt( 1992)
Ping (1987)
Slaughter and Viereck (1986)
Slaughter and Viereck (1986)
Slaughter and Viereck (1986)
Slaughter and Viereck (1986)
Slaughter and Viereck (1986)
tion appears as runoff from a small taiga drainage
basin near Fairbanks, which implies that the remain-
der appears as evapotranspiration, a value equivalent
to 31% of calculated PET (Dingman 1971). Thus, al-
though interior Alaska is semiarid (Van Cleve et al.
1991) to subhumid (D. K. Swanson, Nat. Resour.
Cons. Serv., pers. commun.), it has relatively low
evapotranspiration rates, permitting wet soils to ex-
ist (Patric and Black 1968 in Slaughter and Viereck
1986). Wetlands supplied solely by precipitation
theoretically could not exist where net evaporative
water balances were negative (Ford and Bedford
1987). Indications that actual evaporative water bal-
ances are positive in the Alaskan taiga help account
for the existence of precipitation-driven wetlands in
this environment.
Solar Radiation
Day length and the angle of incidence of solar ra-
diation vary with latitude and the time of year. Con-
sequently, average daily solar radiation is unevenly
distributed throughout the year at northerly taiga lati-
tudes (Table 1) but more uniformly distributed at
southerly latitudes (Strahler 1963:196). Seasonal
radiation balances also vary widely in taiga regions
(Pruitt 1978:8). An excess of outgoing long-wave
radiation over incoming short-wave radiation under
clear winter skies makes polar regions net heat sinks
(Strahler 1963:206, Jayaweera et al. 1973).
Vegetation modifies the energy flux between the
earth and atmosphere in significant ways, including
influencing permafrost formation and the magnitude
of seasonal frost phenomena in soils (Benninghoff
1963). Black spruce canopies intercept incoming
short-wave solar radiation and reduce incident radia-
tion reaching forest floors (Petzold 1981, Slaughter
1983). In addition to the effects of vegetation, topog-
raphy strongly controls local climatic conditions
through its influence on the intensity and duration of
solar radiation incident on the ground surface
(Slaughter and Viereck 1986, Van Cleve et al. 1991).
Topographic control of microclimates may be un-
derstood through the concepts of potential insolation
and equivalent latitude (Dingman 1971, Koutz and
Slaughter 1973, Dingman and Koutz 1974). Lee
(1964 in Dingman 1971) provided an equation that
relates slope inclination, aspect (azimuth), and actual
latitude to an equivalent latitude in terms of solar
radiation (potential insolation) striking a horizontal
surface. Equivalent latitude affects the distribution of
permafrost (Dingman 1971, Koutz and Slaughter
1973, Dingman and Koutz 1974, Collins et al. 1988)
and forest communities (Figure 3) in interior Alaska.
-------
Black Spruce and the Taiga Environment
EQUIVALENT
LATITUDE (deg N)
Populus
tremuloides
Picea glauca
STAND TYPE
Picea
mar/ana
Figure 3. Equivalent latitudes for several forest research stands at 65 degrees N latitude
(Slaughter and Viereck 1986).
PERMAFROST
Soil, rock, or other substrates that continuously
remain at temperatures below 0°C for >2 yr areper-
mafrost (Brown and Pewe 1973,Pruitt 1978:17-18).
The physical characteristics of permafrost substrates
strongly influence taiga ecosystems, including wet-
lands and wetland functions. This section discusses
permafrost distribution, formation, and degradation;
geomorphic features associated with permafrost; and
the effect of permafrost on soil moisture.
Distribution
Permafrost may be continuous or discontinuous
in its distribution (Pewe 1975:44). Across North
America, the geographic zone of continuous perma-
frost is more or less coincident with the Arctic (tun-
dra) and the zone of discontinuous permafrost with
the Subarctic, which coincides with all but the south-
ernmost portion of the taiga (Pruitt 1978, Ping et al.
1992; cf. maps in Brown and Pewe [1973], Bliss
[1981], and Oechel and Lawrence [1985]). In
Alaska, the Brooks Range roughly separates con-
tinuous permafrost from the zone of discontinuous
permafrost (Figure 4) extending southward nearly to
the coast of the Gulf of Alaska (Brown and Pewe
1973). Permafrost is encountered very rarely in
southern Alaska, where mean annual air tempera-
tures are warmer than in the Interior (Pewe 1975:44,
Ping et al. 1992). Permafrost occurs in mountains in
areas where it is absent at lower elevations (Brown
and Pewe 1973).
Formation and Degradation
Permafrost forms or degrades in response to the
thermal balance of the ground (Pewe 1975:47). Fluc-
tuations in thermal balances of soils may manifest
themselves rapidly in "warm" frozen soils (i.e., only
slightly below 0°C) typical of the zone of discon-
tinuous permafrost because the amount of heat gain
necessary to induce thaw is less than for "cold" per-
mafrost (Pewe 1975:47, Ping et al. 1992). Factors in-
fluencing this balance include regional climate,
vegetation, and topography, which in turn influence
microclimatic conditions such as snow cover
(Brown 1963, Washburn 1973, Pewe 1975:47, Ping
1987, Collins et al. 1988).
Relict permafrost can occur where the mean an-
nual air temperature (MAAT) is <0°C, but the -1°C
or -2°C isotherm is the southern limit of equilibrium
permafrost distribution (Brown and Pewe 1973, Ping
et al. 1992). Mean annual ground temperatures are
3.6°C warmer than MAATs in disturbed terrain
(Haugen et al. 1983), which may support the -2°C
MAAT limit for discontinuous permafrost. Warmer
-------
m
Functional Profile of Black Spruce Wetlands in Alaska
soil temperatures occur where winter snow cover is
continuous as compared to areas without continuous
cover (Ping 1987).
Surface organics affect permafrost formation and
degradation (Harris 1987). Organic mats have low
thermal diffusivities when dry, inhibiting heat flow
into underlying mineral soil, but have higher
diffusivities when wet, allowing evaporative cooling
of the ground surface (Riseborough and Burn 1988).
In addition, saturated, frozen peat conducts heat bet-
ter than drier, thawed peat so that the organic layer
impedes summer heat transfer into the ground more
than winter transfer to the atmosphere (Brown and
Pewe 1973). Permafrost degrades (i.e., seasonal
thaw increases) following removal of forest vegeta-
tion by fire (Viereck and Foote 1919b, Viereck 1982)
or mechanical disturbance (Dyrness 1982, Viereck
1982, Evans et al. 1988). Land clearing at an interior
Alaska site raised mean annual soil temperature
(MAST) by 3.4°C and caused the permafrost table to
retreat to ~9 m below the surface after a period of 34
yr (Ping 1987). Conversely, permafrost aggrades as
mature forest communities develop and insulate soil
surfaces (Viereck \913b, 1983; Ping et al. 1992).
Thaw phenomena occur where ground ice may
be present in soil pores, ice seams or lenses, massive
wedges, pingos, or buried masses (Pewe 1975:48-
49). Thermokarst topography results when perma-
frost thaws and "creates an uneven topography
which consists of mounds, sinkholes, tunnels, cav-
erns, short ravines, lake basins, and circular low-
lands caused by melting of ground ice" (Pewe
1975:65). Thawing of large ice masses, which can be
initiated by loss of vegetative cover (Brown 1963,
Washburn 1973, Pewe 1975:65), can produce strik-
ing features such as thermokarst pits; flowing water
intercepted by these features can accelerate their
formation (Pewe 1982:34-40).
Continuous;
Permafrost:
Discontinuous
Permafrost
No Permafrost
Figure 4. Permafrost distribution in Alaska (Ping et al. 1992)
-------
Black Spruce and the Taiga Environment
Geomorphic Features
Water interacts with permafrost to produce inter-
esting geomorphic features (Table 2). Palsas and
peat plateaus are raised permafrost landforms occur-
ring in peatlands (Zoltai 1972). Palsa and peat pla-
teau formation and degradation are sensitive to
vegetative cover and climatic conditions, including
wind and snow cover (Thie 1974, Kershaw and Gill
1979, Seppala 1982, Laprise and Payette 1988).
Palsas may be initiated by wind scour on a peatland
surface (Seppala 1982). Moisture migrating to the
frozen core of a palsa produces segregated ice, raises
the palsa surface, and enables further wind scour
(Brown and Pewe 1973, Pewe 1975:48, Kershaw
and Gill 1979, Seppala 1982).
Open-systempingos form in colluvium and val-
ley fill material near slope bases, often with south or
southeast aspects and muskeg or "bog" vegetation
around, but not on, the pingos (Holmes et al. 1963,
Brown and Pewe 1973, Pewe 1975:56, Ferrians
1988). Patterned ground, with polygons typically 3
to 12 m across in interior Alaska (Pewe 1982:28),
occurs both in the zone of continuous permafrost,
where ice wedges are generally active (i.e., still
growing), and in the zone of discontinuous perma-
frost, where wedges may be active or inactive
(Brown and Pewe 1973, Hamilton et al. 1983). Inac-
tive wedges may partially or completely thaw and
leave casts useful for studying paleoenvironments
(Brown and Pewe 1973, Pewe 1975:52-56).
Fire (Pewe 1982:35, Zoltai 1993), or windthrow
that raises tip-up mounds (Wallace 1948), may ini-
tiate thaw and surface subsidence. Ponded water and
sediment are heated by the sun (Pavlov and Are
1984) to form thaw lakes. Suggestions that thaw
ponds and lakes are cyclic phenomena (Wallace
Table 2. Permafrost-related geomorphic features of wetlands
Geomorphic
Feature
Palsa
Peat Plateau
Pingo
Patterned
Ground
Ice Wedge
Thaw Lake
Description
Peat-covered mound or hummock from -0.1 to 10m in
height and from ~3 to 100 m in diameter that contains a core
of segregated ice and is found in peatlands
Landform with an internal structure similar to a palsa but
having a flat surface that may cover several square
kilometers
Large mound or hill ranging from 30 to 1,000 m in diameter
and from 3 to 70 m in height and containing massive ice
heaved above the surrounding landscape by artesian or
hydrostatic pressure and ice crystallization pressure
The expression of an underlying polygonal pattern of ice
wedges on the surface of the ground; may also occur through
intense seasonal frost processes in nonpermafrost areas with
severely maritime climates and low mean annual
temperatures
Massive structure ranging from 0.01 to 3 m in width and 1 to
10 m in height when viewed in transverse section (i.e., end-
on view) and up to 15 m in length when viewed in
longitudinal section (i.e., face-on view); active ice wedges
grow by periodic cold-induced vertical cracking that allows
surface water to enter the cracks and refreeze
Cave-in lake on flat or gently sloping terrain underlain by
fine-grained sediments formed when water ponds in a
thermokarst depression and promotes radial thaw and bank
caving; thaw may continue for long periods of time with
eventual coalescence of ponds into larger lakes
Source
Brown and Pewe (1973),
Pewe (1975:66), Kershaw
and Gill (1979), Seppala
(1982), Natl. Wetlands
Working Group
(1988:417-420)
Kershaw and Gill (1979)
Holmes et al. (1963),
Brown and Pewe (1973),
Pewe (1975:56), Ferrians
(1988)
Brown and P6we (1973),
Henderson (1968)
Pewe (1975:49),
Lachenbruch (1962 in
Pewe 1975:51)
Wallace (1948), Hopkins
etal. (1955:140), Hopkins
and Kidd (1988)
-------
m
Functional Profile of Black Spruce Wetlands in Alaska
1948, Drury 1956:103, Viereck 1970) are supported
by peat stratigraphy showing episodes of fire-in-
duced permafrost degradation followed by peat ac-
cumulation and eventual permafrost aggradation
(Zoltai 1993).
Effect on Soil Moisture
Permafrost profoundly affects soil moisture by
forming a relatively impermeable zone in the soil
profile, which often retains water near the ground
surface (Dingman 1975:42, Pruitt 1978:21, Ping et
al. 1992). Many wetlands in interior and arctic
Alaska thus exist as a result of permafrost (Batten
1990). Permafrost a^o influences physical phenom-
ena such as the hydrologic characteristics of water-
sheds (Dingman 1975:2).
Cold, wet soils on permafrost sites, in part, con-
trol ecologic processes, including typical vegetation
communities and their successional development
(Viereck 1970, Van Cleve et al. 1991). For example,
black spruce occupies the coldest, wettest sites sup-
porting forest stands in interior Alaska (Van Cleve
and Yarie 1986). Nevertheless, factors such as fire or
land-clearing activities may allow rapid thawing of
permafrost, drainage of soils, improved nutrient sta-
tus, and change in vegetation communities or fea-
sible land uses (Viereck 1973a; Van Cleve, Dyrness
et al. 1983; Ping 1987; Ping et al. 1992).
TAIGA ECOSYSTEMS
Frequent disturbance by the forces of nature cre-
ates the mosaic of plant communities and ecosys-
tems characteristic of the taiga. One such force,
Pleistocene glaciation and subsequent deglaciation,
created the context within which present-day taiga
ecosystems have developed. This section describes
the succession of Holocene plant communities,
zones of taiga vegetation, representative present-day
communities containing black spruce, and processes
that account for the dynamic nature of taiga ecosys-
tems in terms of perturbation and ecologic succes-
sion.
Paleoecology
Modern taiga ecosystems developed following
deglaciation of northern North America, although
much of Alaska (Pewe 1975:21-24) and portions of
Yukon Territory (Hughes et al. 1981) were not gla-
ciated during the Pleistocene. Nonetheless, the Pleis-
tocene environment differed from that of today. A
largely treeless (Matthews 1970) steppe-tundra of
grasses and forbs (Ager 1975:87), the Mammoth
Steppe (Guthrie 1990:226-272), covered unglaciated
terrain during the Wisconsinan glacial stage, al-
though scattered stands of spruce may have persisted
in central Alaska (Pewe 1975:87).
After local deglaciation -14,000 yr BP (e.g.,
Prest 1976 in Ritchie et al. 1983), much of interior
Alaska (Table 3) and northwestern Canada (Table 4)
supported herbaceous or shrub-tundra vegetation.
White spruce (Picea glauca) appeared ~ 10,000 yr
BP in the Mackenzie Delta, -8,500 yr BP in eastern
Alaska (Edwards and Brubaker 1986), and as late as
-7,700 yr BP for more easterly areas of the North-
west Territories (MacDonald 1983). Black spruce
became abundant 7,000 to 6,000 yr BP (Edwards
and Brubaker 1986, Cwynar 1988, Cwynar and
Spear 1991) and, with local exceptions, has persisted
in boreal forest of northwestern Canada and interior
Alaska.
Climatic cooling after -5,000 yr BP (MacDonald
1983, Ritchie et al. 1983), and apparent changes in
soil moisture at some sites, altered plant communi-
ties. Black spruce woodlands in central Yukon were
replaced by shrub tundra (Cwynar and Spear 1991)
and alder (Alnus sp.) invaded a southwestern Yukon
forest-tundra site, which subsequently fluctuated
between abundant sedge, juniper (Juniperus sp.),
and ericaceous vegetation and abundant resin birch
(Wang and Geurts 1991). The cooler climate caused
the treeline to retreat southward in northern Canada,
but little evidence for this has been found in Alaska
(Viereck and Van Cleve 1984).
Zones of Taiga Vegetation
Within the North American taiga, tree size and
canopy cover vary with latitude (Bliss 1981, Rowe
1984, Oechel and Lawrence 1985) and form four
zones of vegetation: forest-tundra ecotone, open
boreal woodland, main boreal forest, and boreal-
mixed forest ecotone (Oechel and Lawrence 1985).
Forest-tundra is the transition between taiga and
tundra (Pruitt 1978:33). In this zone, tundra is inter-
spersed with sparse or clumped white and black
spruce with prominent lichen ground cover; tama-
rack (Larix laricina) may occur on wetter sites
(Zoltai, Tarnocai et al. 1988; Timoney et al. 1992).
The relatively broad zone of forest-tundra found in
10
-------
Black Spruce and the Taiga Environment
Table 3. Paleoecologic history of black spruce in interior Alaska.
Event
Wisconsinan g'laciation -
cold, dry climate
Deglaciation - warmer,
moister climate
Invasion by spruce
Black spruce abundant -
cooler, moister climate
Time
Period
(yrBP)
> 14,000
14,000
to 9,000
8,500 to
7,000
6,500 to
Present
Vegetation
Type
Steppe-Tundra
Shrub Tundra
Boreal Forest
Boreal Forest
Key Taxa
Grasses, Artemisia, other forbs1
Graminoids, Artemisia, shrub birches (Betula
spp.)2
White spruce, paper birch (Betula papyri/era),
resin birch (Betula glandulosa), alder (Alnus
spp.)2
White spruce, black spruce, paper birch
(declining), alder, willows (Salix spp.), dwarf
arctic birch (Betula nana), Ericales "
l.Ager (1975:87-88)
2. Edwards and Brubaker (1986)
3. Hamilton etal. (1983)
4. Thorson and Guthrie (1992)
5. Pewe (1975:88)
Table 4. Paleoecologic history of black spruce in Yukon and western Northwest Territories.
Event
Wisconsinan glaciation
- cold, dry climate
Deglaciation - warmer,
moister climate
Increase of woody
vegetation
Invasion by spruce
Black spruce abundant
- cooler climate
Local decline of black
spruce - SW Yukon -
drier climate
Local invasion of pine -
SW Yukon
Time
Period
(yrBP)
> 14,000
14,000 to
11,000
11, 000 to
9,500
9,500 to
6,500
6,500 to
4,000
4, 100 to
1,900
1,900 to
Present
Vegetation
Type
Mostly
covered by ice
sheet
Herb Tundra
Shrub Tundra
and Deciduous
Woodland
Boreal Forest
and Shrub
Tundra
Boreal Forest
and Shrub
Tundra
Boreal Forest
Boreal Forest
Key Taxa
Grasses, Artemisia
Balsam poplar (Populus balsamifera), Artemisia,
shrub birches, American green alder (Alnus
crispa), grasses, willows1"2
White spruce, juniper, American green alder,
balsam poplar, quaking aspen (Populus
tremuloides), willow, shrub birches2"5
Black spruce, American green alder, white
spruce2"3
White spruce, juniper, lodgepole pine (Pinus
contondf
lodgepole pine3
1. Ritchie et al. (1983)
2. Cwynar(1988)
3. Cwynar and Spear (1991)
4. Wang and Guerts (1991)
5. MacDonald (1983)
11
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Functional Profile of Black Spruce Wetlands in Alaska
northern Canada (Timoney et al. 1992) is much re-
duced in Alaska because the Brooks Range coin-
cides with northern limit of trees (except balsam
poplar) (Viereck 1975, 1979). Forest-tundra does
occur in western Alaska, however (D. K. Swanson,
Nat. Resour. Conserv. Serv., pers. commun.).
White and black spruce stands with patchy li-
chen cover (e.g., Cladina mitis, C. rangiferina, C.
stellaris [=alpestris]) dominate open boreal wood-
land, but tamarack, paper birch, quaking aspen, and
balsam poplar occur on suitable sites (Oechel and
Lawrence 1985; Zoltai, Tamocai et al. 1988). Fur-
ther south, the main boreal forest contains closed-
canopied stands of conifers including white spruce,
black spruce, tamarack, jack pine (Pinus
banksiana), lodgepole pine, balsam fir (Abies
balsamea), subalpine fir (A. lasiocarpa), and hard-
woods including quaking aspen, balsam poplar, and
paper birch (Oechel and Lawrence 1985; Zoltai,
Taylor et al. 1988). The boreal-mixed forest ecotone
lies at the southern edge of the taiga and thus does
not occur in Alaska.
Black Spruce Communities
Representative types of interior Alaska's mature
forest communities (Foote 1983) fall into two ma-
jor groups: the white spruce site type and the black
spruce site type (Table 5). Black spruce stands, pure
or codominant with aspen, birch, or white spruce,
often occur on slopes and cool, moist valley bot-
toms (Foote 1983:28) and may be underlain by per-
mafrost (Viereck and Little 1972:18). Black spruce
also occurs on relatively dry, nutrient-poor residual
soils over bedrock (M.T. Jorgenson, ABR, Inc.,
pers. commun.).
Tree species commonly associated with black
spruce in Alaska include white spruce, tamarack,
paper birch, and sometimes quaking aspen. White
spruce occurs in mixed stands with black spruce
near treeline, near the base of south-facing slopes,
and as a successional stage on floodplains (Viereck
1970, 1975; Viereck and Dyrness 1980; Foote
1983:43-46). Although tamarack has a more re-
stricted range than black spruce in Alaska and is dis-
junct from the remainder of the North American
population (Harlow and Harrar 1968:116-117,126;
Viereck and Little 1972:50; Zoltai 1973), it can be
found in mixed stands with black spruce in wet low-
lands of the Interior (Viereck and Dyrness 1980; D.
K. Swanson, Nat. Resour. Conserv. Serv., pers.
commun.). Paper birch, often an element of post-fire
succession (Viereck and Little 1972:138), grows in
mixed stands with black spruce on mesic sites but
tends to die out in spruce stands more than 120 yr
old (Viereck and Dyrness 1980, Foote 1983:32-35).
Aspen frequently occurs in pure stands (Viereck and
Little 1972:76-77) but sometimes is mixed with
black spruce in successional stands on warm sites
(Foote 1983:29-32) or well-drained floodplain ter-
races (Viereck and Little 1972:16-17
Ecologic Succession
Periodic disturbances by fire (Viereck 1973a,
1975, 1983; Van Cleve, Dyrness et al. 1983; Dyrness
et al. 1986) and fluvial processes (Drury 1956;
Viereck 1970, 1975; Van Cleve et al. 1980, Walker
et al. 1986) "reset" ecologic succession in taiga eco-
systems and create a mosaic of plant communities
(Van Cleve et al. 1991). Fire frequency varies across
the North American taiga (Table 6) with less fre-
quent fires in humid eastern taiga than in drier west-
em areas (Viereck and Schandelmeier 1980:12-13).
Fire is a major allogenic (external) force initiating
secondary succession in the taiga (Kimmons and
Wein 1986).
Fires can leave the forest floor lightly burned,
scorched, or unburned (Dyrness and Norum 1983)
or, if severe, expose mineral soil, which is a favor-
able substrate for germinating seeds (Noste et al.
1979a). In addition, fire may eliminate buried, viable
seeds and underground parts of shrubs in severely
burned patches but not in lightly burned patches
(Viereck and Schandelmeier 1980:46-47). Varying
moisture content of forest floor organic material ac-
counts for the mosaic pattern associated with taiga
fires (Dyrness and Norum 1983). Post-fire succes-
sion may start with germination of seeds arriving
from off site, germination of seeds surviving on site,
or resprouting of surviving vegetation (Dyrness et al.
1986). Black spruce has semiserotinous cones that
retain seeds for periods of years (Zasada 1986) and
thus black spruce sites exhibit greater reproduction
from on-site seed sources and from resprouting than
do white spruce sites (Foote 1983:99-100).
No universal sequence of taiga succession exists
(Viereck 1983) because successional sequences fol-
lowing fire depend on fire characteristics and sever-
ity, prefire vegetation, regional patterns, site aspect
12
-------
Black Spruce and the Taiga Environment
Table 5. Representative black spruce community types of interior Alaska (Foote 1983).
Black Spruce Site
Type
Picea mariana/
Vaccinium uliginosum -
Ledum groenlandicum/
Pleurozium schreberi
Picea mariana/
feathermoss - lichen
Picea mariana/
Sphagnum spp. -
Cladina spp.
Populus tremuloides -
Picea mariana/Cornus
canadensis
Picea mariana - Betula
papyrifera/Vaccinium
uliginosum - Ledum
groenlandicum
Picea mariana - Picea
glauca/Betula
glandulosaAichen
Description
Black spruce, bog blueberry (Vaccinium
uliginosum), Labrador-tea (Ledum
groenlandicum), feathermoss on slopes
and valley bottoms
Similar to preceding type, but abundant
lichens are mixed with the feathermoss
Black spruce, Sphagnum mosses with
intermixed lichens on north-facing slopes
and wetter valley bottoms
Quaking aspen, black spruce, bunchberry
(Cornus canadensis) on drier sites
Paper birch, black spruce, bog blueberry,
Labrador-tea, feathermoss in slightly
wetter sites than preceding community
type
White spruce, black spruce, resin birch,
lichens on drier sites near treeline
Comments
Lichens are not abundant, but
American green alder, resin birch,
and mounds of Sphagnum mosses
frequently occur
Sphagnum spp. are not common
Tamarack may occur in these
stands (Viereck and Little
1972:18)
Succeeds to black spruce and
feathermoss
Succeeds to a black spruce
community
May not succeed to pure stands of
either spruce species or might
become monospecific black
spruce in the rare event that fire
did not occur for a long time
(Strang and Johnson 1981)
Table 6. Fire recurrence intervals for North American taiga locations.
Location
Newfoundland
New Brunswick
Labrador
Quebec
Quebec
Northwest Territories
(transec., Hudson Bay
to Mack nzie River)
Northwest Territories
and Yukon (Mackenzie
River)
Alaska (Porcupine
River)
Alaska (interior taiga)
Recurrence Interval (yr)
400 (includes man-caused fires)
230 to > 1,000 (varies by community type and
elevation)
"Extremely long" (most stands >250 yr old)
~ 1 90 (30-y r period of record)
10,417 (single decade in 30-yr period)
— 13° (spruce/feathermoss)
343 (40-yr period)
216 to 717 (single decades in 40-yr period)
80 to 90
<60 (spruce stands)
100 to 200
<400 (longest reported interval)
Source
Wilton and Evans (1974 in
Viereck and Schandelmeier
1980:13)
Wein and Moore (1977)
Foster (1984)
Payetteet al. (1989 in
Timoney and Wein 1991)
Cogbill(1985)
Timoney and Wein (1991)
Rowe et al. (1974 in Viereck
1983)
Yaric (1981 in Dyrness et al.
1986)
Viereck (1983), Gabriel and
Tande (1983 in Dyrness et
al. 1986)
13
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Functional Profile of Black Spruce Wetlands in Alaska
and slope (potential insolation), site moisture, prox-
imity of seed sources, and other factors (Viereck
1973a, Viereck and Schandelmeier 1980:47-49,
Oechel and Lawrence 1985, Van Cleve et al. 1991).
Viereck and Schandelmeier (1980:47-55) identify
black spruce/feathermoss and black spruce/lichen
woodland patterns of succession. Black spruce/
feathermoss succession has six generalized stages:
newly burned, moss-herb, tall shrub-sapling, dense
tree, hardwood, and spruce (Foote 1983:49-100).
The black spruce/lichen woodland pattern of suc-
cession (Viereck and Schandelmeier 1980:47-55)
occurs in three stages: pioneer mosses and liver-
worts, occasionally with substantial cover by vascu-
lar plants; open-canopy tree cover over fruticose
lichens and ericaceous shrubs, sometimes with
feathermosses; and increasing tree and feathermoss
cover with lichen dominance shifting to favor
Cladina stellaris and C. rangiferina over Cladonia
crispata (Viereck and Schandelmeier 1980:47-55).
Many black spruce/lichen stands are not wetlands
(D. K. Swanson, Nat. Resour. Conserv. Serv., pers.
commun.). Finally, hydric (wet) black spruce sites,
such as floodplain terraces escaping fire for long
periods, may succeed to treeless wetlands or cycle
between such wetlands and black spruce (Drury
1956, Viereck 1970, Viereck and Schandelmeier
1980:53).
Post-fire secondary succession in black spruce
often produces little change in the species composi-
tion of vascular plants, especially for incompletely
burned stands (Black and Bliss 1978, Jasieniuk and
Johnson 1982, Viereck 1983, Oechel and Lawrence
1985, Zoladeski and Maycock 1990), and differ-
ences between heavily and lightly burned stands rap-
idly diminish with time (Viereck and Foote 1979a).
In contrast, species composition of nonvascular
plants changes with time. Black and Bliss (1978),
identified four stages of post-fire succession for
Picea mariana/Vaccinium uliginosum communities
in the Northwest Territories: three similar to those of
black spruce/lichen woodland (above) and a fourth
characterized by increased cover and density of
black spruce from vegetative reproduction and in-
creased cover by lichens such as Cladina stellaris, C.
mitis, and C. rangiferina. The fourth stage occurs
after 200 yr but is rare because of fire. Post-fire li-
chen-bryophyte succession in the absence of change
in vascular species composition also occurs in Picea
mariana/Cladina stellaris woodland in northern
Quebec (Morneau and Payette 1989).
Erosion and deposition in river floodplains dis-
rupt succession by undercutting and washing away
the alluvial deposits upon which older plant commu-
nities have been established and by forming new
depositional surfaces upon which primary succes-
sion can take place (Van Cleve et al. 1980, Kimmins
and Wein 1986, Walker et al. 1986). Young surfaces
increase in height with seasonal flooding and silt
deposition, gradually building terraces (Walker et al.
1986) and altering physical and chemical site condi-
tions (Van Cleve et al. 1980). Active movement of
river channels and cycles of alluviation and
downcutting produce a mosaic of habitats in river
floodplains (Drury 1956:15-18, Pewe 1975:68).
Given sufficiently long periods without fire, black
spruce may replace white spruce on old terraces as
permafrost forms and soils become waterlogged
(Viereck 1970, Zasada 1986).
Succession-Permafrost Relationships
Succession in subarctic taiga forest affects aggra-
dation and degradation of permafrost. Fire or other
disturbance can remove vegetative cover and reduce
forest floor thickness, increasing depth of thaw in
permafrost soils (Brown 1963, Viereck 1973&,
Viereck and Foote 1919b, Van Cleve and Viereck
1983, Viereck and Van Cleve 1984, Dyrness et al.
1986, Ping 1987, Evans et al. 1988). Thickness of
the active layer ("the layer of ground above the per-
mafrost which thaws and freezes annually" [Gabriel
and Talbot 1984:7]) in a burned stand of black
spruce increased for 9 yr following an Alaskan for-
est fire, reaching a depth of 1.87 m, and a bladed fire
line thawed to 2.27 m after 8 yr (Viereck 1982). An
experimental burn that only slightly reduced thick-
ness of the organic layer produced only small in-
creases in thaw depth whereas treatments that
mechanically removed one half of the organic layer
or the entire organic layer produced much greater
depths of thaw (Dyrness 1982).
Conversely, recovery of vegetation and accumu-
lation of organic matter during secondary succession
can decrease the depth of the active layer (Heilman
1966, Viereck 1983). In upland stands of black
spruce, feathermosses and some Sphagnum mosses
become abundant in the dense tree stage of develop-
ment 40 to 60 yr after fire; active layer thickness
14
-------
Black Spruce and the Taiga Environment
decreases to prefire values at about this time (Zoltai
1975, Van Cleve and Viereck 1983), or at least
within 100 yr (Viereck and Van Cleve 1984). Simi-
larly, permafrost attributed to a thick insulating layer
of moss and organics was present in a mixed flood-
plain stand of 200-yr old white and black spruce
(presumably of primary successional origin) but ab-
sent in three younger stands (Viereck 1970).
BLACK SPRUCE SPECIES
CHARACTERISTICS
Black spruce is an important, widespread species
in northern North America and occurs in a variety of
environmental settings. Black spruce has genetic
potentials that govern its response to various envi-
ronmental conditions in terms of appearance, toler-
ance of those conditions, and method of
reproduction. The following discussion outlines the
distribution and characteristics of black spruce as a
species, range of environments within which black
spruce occurs, and adaptations of black spruce to the
conditions with which the species must cope.
Distribution
Black spruce occurs across North America from
Labrador south to New Jersey and Pennsylvania in
the east and from British Columbia north to Yukon
Territory and Alaska in the west (Harlow and Harrar
1968:124-127, largely coincident with the taiga as
defined by Pruitt (1978:1-7). Although black spruce
grows on extensive upland areas in the northern por-
tion of its North American range, to the south this
species is often restricted to peatlands and may oc-
cur as a pioneer tree on floating mats of vegetation
(Harlow and Harrar 1968:125). Black spruce is re-
stricted to wetlands in kettle-hole depressions at the
southern edge of its range in Minnesota (P. H.
Glaser, Univ. Minn., pers. commun.).
Black spruce dominates the forest-tundra south-
east of a point between Great Bear and Great Slave
lakes, Northwest Territories; white spruce dominates
to the northwest of this point (Timoney et al. 1992).
Although white spruce also defines the northern and
western limits of the taiga in Alaska (Viereck 1975),
black spruce is the major conifer of the open boreal
woodland zone to the south of the forest-tundra
(Oechel and Lawrence 1985) and covers 44% of in-
terior Alaska (Viereck et al. 1986). Black spruce
occurs from the southern slopes of the Brooks Range
southward to the Kenai Peninsula and from the Ca-
nadian border westward to Norton Sound, although
it is absent on the Yukon-Kuskokwim Delta and in
the western portion of the Alaska Range (Viereck
and Little 1972:51-52).
Treelines are influenced by latitude, altitude, and
climate, which perhaps limit forest growth through
low summer temperatures (Dahl 1986). Additional
factors include past climate, glaciation, and fire
(Oechel and Lawrence 1985). Latitudinal treeline for
black spruce across central North America is the tun-
dra-taiga boundary, but white spruce occurs on this
boundary in western Canada (Timoney et al. 1992)
and Alaska (Viereck 1979). In Alaska, black spruce
commonly grows on cold, wet sites of less than 610
m elevation, but the altitudinal treeline may reach
823 m (Viereck and Little 1972:51).
Growth Forms and Densities
Black spruce trees reach heights of 9 to 12 m and
diameters of 150 to 300 mm (Harlow and Harrar
1968:125) on favorable sites. Individual trees can
reach heights of 24 m in Minnesota (Heinselman
1963). In Alaska, these spruces more typically are
4.5 to 9 m tall and 75 to 150 mm in diameter with
"narrow pointed crown[s]" (Viereck and Little
1972:51). The species also may grow as a shrub,
generally in the shape of a small tree, or as krumm-
holz (stunted, scrubby, twisted growth forms of spe-
cies genetically capable of tree growth [Gabriel and
Talbot 1984:63]) at treeline (Payette et al. 1982).
Specific growth forms depend upon environmental
conditions experienced during the lives of individual
trees and include mat, infranival cushion, supranival
skirted, whorled, and tree shapes (Lavoie and
Payette 1992).
The stem density (Table 7) and canopy coverage
of black spruce stands vary with site conditions and
stand age. In the forest-tundra, trees may occur as
clonal stands or single stems (Timoney et al. 1992)
and by definition reach very low densities as the
transition from taiga to tundra occurs. Black spruce
in Alaska occurs in communities with crown cano-
pies classified as closed (60-100% cover), open (25-
60% cover), and woodland (10-25% cover) (Viereck
et al. 1992). Black spruce woodlands occupy transi-
tions between treeless wetlands and drier forests and
also occur on dry uplands and at treeline, sometimes
in association with white spruce (Viereck 1979,
-------
Functional Profile of Black Spruce Wetlands in Alaska
Viereck and Dyrness 1980). Closed-canopied forests
characterize the main boreal region of Canada
(Zoltai, Taylor etal. 1988).
Adaptations
Factors such as soil moisture, soil chemistry,
competition with other species, and response to
browsing influence the distribution and abundance
of black spruce. In terms of moisture tolerance, black
spruce occurs on well-drained soils over much of its
range but also grows in Sphagnum peatlands
(Harlow and Harrar 1968:125). In Alaska, black
spruce dominates cold, wet sites (Van Cleve and
Yarie 1986, Viereck et al. 1986) but also occurs on
drier, nutrient-deficient sites (M. T. Jorgenson, ABR,
Inc., pers. commun.). This distribution indicates that
black spruce tolerates a wide range of soil moisture
conditions.
Silvicultural drainage of forest soils in Europe
(Putkisto 1980, Remrod 1980, Vasander 1984) and
North America (Haavisto and Wearn 1987,
Harkonen 1987, Hillman 1987) has been attempted
or proposed to promote tree growth, including that of
black spruce. In Alberta, leader growth in black
spruce did not initially respond to drainage (Lieffers
and Rothwell 1987), but after a 3- to 6-yr delay tree
ring growth increased to a maximum rate, which oc-
curred 13 to 19 yr following drainage (Dang and
Lieffers 1989). Wang et al. (1985) noted similar
growth responses in black spruce on drained sites.
Although wet sites do not provide optimum condi-
tions for growth of black spruce, the species is
adapted through a strategy of nutrient conservation
to occupy these poor environments (Van Cleve and
Dyrness 1983a).
Black spruce occupies sites characterized by low
pH (Table 8) in Alaska (Van Cleve, Oliver et al.
1983) and the Northwest Territories (Jasieniuk and
Johnson 1982). Compared to other interior Alaska
forest types black spruce forest floors have low base
element saturation; long turnover times for organic
matter, nitrogen (N), phosphorus (P), potassium (K),
calcium (Ca), and magnesium (Mg); high biomass
accumulation; and low element (N, P, K, Ca, Mg)
concentrations (Van Cleve, Oliver et al. 1983). Sub-
strate quality in black spruce stands is poor
(Flanagan and Van Cleve 1983). Low temperature
and poor litter quality interact to reduce mineraliza-
tion rates, potentially contributing to successional
changes leading to sites dominated by black spruce
(Chapin 1986). Black spruce requires only about
one-third as much N, P, and K as white spruce and as
little as one-tenth as much as quaking aspen (Van
Cleve, Oliver et al. 1983).
Black spruce competes with other plants, such as
mosses (Van Cleve and Viereck 1983, Oechel and
Table 7. Stem densities of several immature and mature black spruce stands, interior Alaska (Foote
1983:43-48,76-92).
Species Composition
Black spruce
Black spruce
Black spruce
Mixed white and black spruce
Site Description
Moist
Mesic
Mesic
Dry treeline
Stand Age (yr)
60 to 130
1 to 5
91 to 200
55 to 195
Stem Density (ha"1)
300 (mature)
18,000
1,700 (mature)
400 (mature)
Table 8. Soil pH at several black spruce sites in interior Alaska.
Stand Location
Upland
Upland
Lowland
Lowland
Number of Stands
4
3
1
1
Material
Organic
Mineral
Organic
Mineral
pH
3.3 to 3.7
4.12 to 5.09
3.60 to 4.80
5.22
Source
Troth etal. (1976)
Nosteetal. (1979b)
Viereck (1970)
Viereck (1970)
16
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Black Spruce and the Taiga Environment
Van Cleve 1986). Mosses efficiently trap nutrients,
which are not available to vascular plants until the
mosses decompose (Oechel and Van Cleve 1986).
Moss production in mature black spruce stands may
exceed tree foliage production by a factor of 3 (Van
Cleve, Dymess et al. 1983) and, coupled with low
rates of decomposition (Van Cleve, Viereck et al.
1983), helps build thick organic layers (Oechel and
Lawrence 1985).
There is some question whether or not black
spruce can persist over long periods in successful
competition with mosses and possible paludification
(the process of bog expansion that occurs as peat ac-
cumulation impedes drainage [Natl. Wetlands Work-
ing Group 1988:438] of forest soils (Viereck 1983).
Sparsely treed Sphagnum bogs develop on north-fac-
ing slopes that have escaped burning for significant
periods (Heilman 1966, 1968). Paludification of
lowland black spruce stands, perhaps coupled with
disturbance that initiates thaw, may form treeless
wetlands (Drury 1956:30-35, Viereck 1970). The
ability of black spruce to persist in the absence of
fire or other disturbance may be inversely related to
the degree of swamping that occurs on a given site.
In some Minnesota peatlands, woody peat is over-
lain by Sphagnum peat indicating the earlier pres-
ence of forest in what are now treeless bog drains
(runoff channels) (Glaser 1987:50-52).
Black spruce is adapted to a low-nutrient envi-
ronment (Bryant and Kuropat 1980, Bryant and
Chapin 1986) through a strategy of nutrient conser-
vation (Van Cleve and Yarie 1986) that includes a
slow growth rate (Bryant et al. 1983). Because
browsing of stress-adapted plants depletes stored,
scarce nutrient capital, chemical compounds that
discourage browsing by herbivores should be
present in such plants (Grime and Anderson 1986).
This expectation is confirmed for black spruce: the
species has a high resin content (Bryant et al. 1983),
herbivorous birds and mammals avoid black spruce
when alternative browse is available (Bryant and
Kuropat 1980), and actual or simulated browsing
severely damages black spruce (Bryant and Kuropat
1980, Fox and Bryant 1984).
Reproduction
Black spruce reproduces by sexual and vegeta-
tive means (Harlow and Harrar 1968:126). Living
Sphagnum mosses provide an adequate seedbed for
black spruce regeneration (Johnston 1977:7), an
adaptive advantage over other tree species (D. K.
Swanson, Nat. Resour. Conserv. Serv., pers.
commun.), but sexual reproduction in black spruce
also is adapted to post-fire regeneration. Seedfall in
undisturbed black spruce stands is gradual and less
intense than in burned stands where seedfall can be
heavy (Viereck and Dyrness 1979, Zasada 1986).
Seedling density increased over a 3-yr period fol-
lowing fire in interior Alaska (Viereck and Foote
1979a). In northern Quebec uplands, sexual regen-
eration is most vigorous from 5 to 14 yr following
fire, perhaps because microclimates for seedling es-
tablishment cool and moisten at this time (Morneau
and Payette 1989); seedling establishment in this
region declines as increasing lichen cover inhibits
spruce germination beginning -20 yr after burning
(Sirois and Payette 1991).
Fire sometimes exposes mineral soil, which pro-
vides the best conditions for germination and estab-
lishment of black spruce (Viereck 1973a, Zasada
1986). Artificial seeding was most successful on
heavily burned plots; germination failed on scorched
or lightly burned plots (Zasada et al. 1983). Seed-
lings established most successfully on lightly and
heavily burned hillside plots but only sparsely estab-
lished on a heavily burned ridgetop following a natu-
ral fire in interior Alaska (Viereck and Foote 1979a).
In general, black spruce regenerates best on heavily
burned sites (Dymess et al. 1986) with unburned tree
crowns holding cones as a seed source (Zasada
1986).
Vegetative reproduction in black spruce occurs
by layering, which is the rooting of lower branches
and growth of new individuals to form a clone
(Zasada 1986). Layering predominates in older, un-
disturbed stands (Zasada 1986) characterized by li-
chens or thick moss layers, which may be
unfavorable for seedling establishment
(Chrosciewicz 1980, Aksamit and Irving 1984,
Morneau and Payette 1989). Vegetative reproduction
can maintain clonal black spruce stands (Legere and
Payette 1981), change mixed stand composition
(Strang and Johnson 1981), or increase stand density
(Black and Bliss 1978).
17
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Functional Profile of Black Spruce Wetlands in Alaska
BLACK SPRUCE WETLANDS
In North American taiga, black spruce, some-
times growing in mixed stands with tamarack, is the
tree species most often associated with treed wet-
lands. Wetlands occupy 20 to 30% of the taiga land-
scape (Zoltai, Tarnocai et al. 1988; Zoltai, Taylor et
al. 1988), although the percentage rises to -50% in
the southern boreal forest (Larson 1991). Hydrologi-
cally linked complexes of groundwater-influenced
communities (fens) surrounding slightly higher, pre-
cipitation-influenced communities (bogs)
(Heinselman 1963, 1970; Glaser et al. 1981), are the
most common of these peat-forming wetlands
(Larson 1991). Black spruce wetlands also occur in
isolated locations to the south of the boreal forest
(Mitsch and Gosselink 1986:288-291, Larson 1991)
and on extensive glaciolacustrine deposits in Minne-
sota (Heinselman 1963, 1970). The following chap-
ter defines terms necessary to understand the
functions of BSWs and describes their classification
and vegetation.
WHAT IS A WETLAND?
The reader should base specific understanding of
the functions of Alaska's BSWs on general familiar-
ity with wetland definitions and characteristics and
wetland classification systems used in northern
North America. The explanatory material contained
in this section of the profile provides such familiar-
ity with terminology and concepts. Additional infor-
mation may be found in the comprehensive wetland
textbook by Mitsch and Gosselink (1993) and the re-
cent National Research Council (1995) report on
wetland characteristics and boundaries.
Definitions and Defining Characteristics
Wetland definitions (Table 9) range from ver-
nacular names (e.g., marshes, swamps, and mires
[Gore 1983, Maltby 1986:28]) to descriptions of
physical, chemical, and biological characteristics
necessary for a wetland to exist (e.g., hydrologic
regime, soils, and vegetation [Gore 1983, Mitsch and
Gosselink 1986:16-20). Definitions may be based on
science or developed for purposes of regulation.
North American wetland definitions generally incor-
porate characteristics of vegetation, soils, and hy-
drology that allow practical delineation of wetland
areas.
Hydrology is "probably the single most impor-
tant determinant for the establishment and mainte-
nance of specific types of wetlands and wetland
processes" (Mitsch and Gosselink 1986:55). The
season, frequency, depth, and duration of saturation
or flooding control development of wetland soils and
vegetation (Lugo, Brown et al. 1990; Maltby 1991).
Wetland hydrology, in turn, is influenced by the
source of water input (precipitation, groundwater
discharge, surface flow); type of water output (sur-
face outflow, groundwater recharge, evapotranspira-
tion); biotic factors (e.g., paludification); energy
inputs (e.g., tides, wind); and the balance between
water input, output, and storage on various time
scales (Mitsch and Gosselink 1986:55-77, Kangas
1990, Maltby 1991). These influences sometimes
make wetland hydrology difficult to measure, but
field indicators and other data sources can verify the
presence or absence of wetland hydrology (Tiner
1989, Natl. Res. Counc. 1995:108-109).
Wetland soils are hydric: "soil[s] that [are] satu-
rated, flooded, or ponded long enough during the
growing season to develop anaerobic conditions in
the upper part" (Natl. Tech. Comm. Hydric Soils
1991:1). These soils are listed in the publication
18
-------
Black Spruce Wetlands
Table 9. Representative wetland definitions.
Purpose and Scope
Wetland Definition
Source
Conservation
(global): Ramsar
Convention on
Wetlands of
International
Impo lance
Especially as
Waterfowl Habitat
"Areas of marsh, fen, peatland or water, whether natural or artificial,
permanent or temporary, with water that is static or flowing, fresh,
brackish or salt including areas of marine water, the depth of which
at low tide does not exceed 6 m [just over 19 ft]"
Maltby
(1991:9)
Science/
classification
(Canada)
"Land that has the water table at, near, or above the land surface or
which is saturated for a long enough period to promote wetland or
aquatic processes as indicated by hydric soils, hydrophytic
vegetation, and various kinds of biological activity that are adapted
to the wet environment"
Tarnocai
(1980/n
Zoltai
1988:3)
Science/
classification
(United States)
"... wetlands must have one or more of the following three
attributes: (1) at least periodically, the land supports predominantly
hydrophytes; (2) the substrate is predominantly undrained hydric
soil; and (3) the substrate is nonsoil and is saturated with water or
covered by shallow water at some time during the growing season of
each year"
Cowardin et
al. (1979:3)
Science/reference
(United States)
".. . an ecosystem that depends on constant or recurrent, shallow
inundation or saturation at or near the surface of the substrate. The
minimum essential characteristics of a wetland are recurrent,
sustained inundation or saturation at or near the surface and the
presence of physical, chemical, and biological features reflective of
recurrent, sustained inundation or saturation. Common diagnostic
features of wetlands are hydric soils and hydrophytic vegetation.
These features will be present except where specific
physicochemical, biotic, or anthropogenic factors have removed
them or prevented their development"
National
Research
Council
(1995:59)
Regulatory (United
States)
"... those areas that are inundated or saturated by surface or ground
water at a frequency and duration sufficient to support, and that
under normal circumstances do support, a prevalence of vegetation
typically adapted for life in saturated soil conditions. Wetlands
generally include swamps, marshes, bogs, and similar areas.
(33CFR328(b); 1984)"
Mitsch and
Gosselink
(1993:27)
Hydric soils of the United States (Natl. Tech. Comm.
Hydric Soils 1991), based on criteria that include
references to soil taxonomy (Soil Surv. Staff 1994)
combined with drainage characteristics, water table
position, soil permeability, and frequency of ponding
or flooding. Redoximorphic features in soils - pat-
terns of color related to chemical reduction or oxida-
tion of iron (Fe) or manganese (Mn) - can be used,
with caution, to assist field identification of aquic
(wet) conditions (J. Bouma, Rep. of Int. Comm. on
Aquic Soil Moisture Regimes, Circular 10).
Wetland plants exhibit structural and physiologi-
cal adaptations to their environment (Larsen
1982:248-257, Mitsch and Gosselink 1986:130-
140). Such plants are hydrophytes: "macrophytic
plant life growing in water, soil, or on a substrate that
is a[t] least periodically deficient in oxygen as a re-
sult of excessive water content" (Tiner 1989:17).
The U.S. Fish and Wildlife Service, in cooperation
with national and regional interagency review pan-
els, has prepared national, regional, and state lists of
vascular plant species that occur in wetlands (Reed
1988:2-7). These species are further rated with re-
spect to their frequency of occurrence in wetlands,
19
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m
Functional Profile of Black Spruce Wetlands in Alaska
some plants being obligate (restricted to wetlands)
and others facultative (not restricted to wetlands)
wetland residents. Weighted sampling procedures
are available to determine whether or not the vegeta-
tion on a given site predominantly comprises hydro-
phytes (Tiner 1989).
Recently, the National Research Council
(1995:64) has suggested that, in the most general
sense, defining characteristics of wetlands are water,
substrate, and biota. This suggestion recognizes that
organisms (e.g., mosses, aquatic invertebrates) other
than vascular plants can serve as biological indica-
tors and that some wetlands have substrates other
than hydric soils (Natl. Res. Counc. 1995:136-137).
Mires
Some BSWs arepeatlands or mires, peat-form-
ing ecosystems having >0.4 m peat thickness and
generally separated into bogs and fens based on veg-
etation, water source, and water chemistry (Table
10), all of which are related variables (Sjors 1950,
1963; Boelter and Verry 1977; Gore 1983; Gabriel
and Talbot 1984:71-72; Zoltai 1988; Swanson and
Grigal 1989). Peat-forming vegetation includes
mosses, grasses and sedges, and woody plants
(Clymo 1983). Bogs are ombrotrophic mires, mean-
ing they receive water exclusively as precipitation
(Gabriel and Talbot 1984:77), which typically has a
low nutrient content (i.e., water that is oligotrophic)
(Gore 1983, Damman 1987). In contrast, fens are
minerotrophic mires (Boelter and Verry 1977, Gore
1983), meaning they receive water that contains
moderate to high concentrations of nutrients (i.e.,
water that is mesotrophic or eutrophic) from contact
with mineral soil (Gabriel and Talbot 1984:71). In-
termediate transition sites or poor fens also occur
Table 10. Representative characteristics of bogs and fens.
Mire
Type
Bog
Poor
Fen
Fen
Rich
Fen
Water Source
Precipitation
(ombrotrophic)
Precipitation/
groundwater
(weakly
minerotrophic)
Precipitation/
groundwater
(minerotrophic)
Precipitation/
groundwater
(highly
minerotrophic)
Trophic
Status
Oligotrophic
Transition
Mesotrophic
Eutrophic
Pore Water
pH
<4.4'
4.5s
<4.66
>4.0 to <4.93
4 4 to 5 62
4.7s
54
5.5 to 6.06
6.8 to 7.94
Pore
Water
Ca+Mg
(mg/L)
<56
<6'
>910
>224
Dominant Vegetation
Sphagnum, lichens, heath shrubs,
stunted trees6'8
Sphagnum, black spruce7
Brown mosses, sedges, forbs, shrub
birches, willows, tamarack7
Flarks: brown mosses, sedges4
Strings: brown mosses, shrub
birch, tamarack, black spruce4
1. Swanson and Grigal (1991)
2. Swanson and Grigal (1989)
3. Comeau and Bellamy (1986)
4. Slack etal. (1980)
5. Zoltai and Johnson (1987)
6. Zoltai (1988)
7. Zoltai, Taylor etal. (1988)
8. Zoltai, Tarnocai et al. (1988)
9. Gauthier (1980 in Zoltai 1988)
10. Schwintzer (1978 in Zoltai 1988)
20
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Black Spruce Wetlands
(Sjors 1950, Comeau and Bellamy 1986).
Peatland communities array along a moisture-nu-
trient gradient (Jasieniuk and Johnson 1982).
Swanson and Grigal (1989) predicted pH class and
thus trophic status of Minnesota mires with a simple
vegetation key based on pH tolerances of common
mire plants. Although all species that grow in raised
bogs also occur in fens, raised bogs can be distin-
guished by the absence of fen indicator species (i.e.,
species restricted to fens) (P. H. Glaser, Univ. Minn.,
pers. commun.). Zoltai and Johnson (1987) charac-
terized plant species associated with classes of
peatlands of various trophic status based on Ca con-
centration. Vegetation responded to small changes in
Ca levels at low Ca concentrations but was less sen-
sitive at higher concentrations.
The reader should note that the Canadian system
of wetland classification defines mesotrophic to en-
compass the majority of fens (Zoltai 1988), which is
at variance with the usage of mesotrophic by
Swanson and Grigal (1989) to represent scarce poor
fens. Also, some European authors (e.g., Eurola et al.
1984) describe oligotrophic wetlands, along with
mesotrophic and eutrophic wetlands, as a subset of
minerotrophic wetlands, reserving ombrotrophic for
mires of the very lowest nutrient status. In contrast,
oligotrophic appears to describe the nutrient status of
ombrotrophic wetlands in the North American litera-
ture. This report follows the Canadian classification
system in usage of mesotrophic and the North
American literature in usage of oligotrophic.
Relationship of Black Spruce Wetlands to Mires
Wetlands with Histosols, soils having >0.4 m of
organic material, are mires, but wetlands with soils
having histic epipedons (organic layers ranging from
0.2 to 0.4 m) are not mires by the Canadian defini-
tion (S.C. Zoltai, Can. For. Serv., pers. commun.).
The 0.4-m criterion for minimum peat depth is based
on the maximum rooting depth of most wetland
plants (Zoltai 1988). Roots of most plants in erica-
ceous BSWs of interior Alaska, however, tend to be
confined to organic soil horizons, even when those
horizons are <0.4 m thick (O.K. Swanson, Nat.
Resour. Conserv. Serv., pers. commun.).
Black spruce wetlands with histic epipedons
form peat and occupy a continuum from mire to sites
possibly influenced by mineral soils (Table 11).
Studies reviewed for this profile did not address po-
tential relationships between organic layer thickness
and mire-like characteristics of wetlands. Neverthe-
less, literature addressing bogs and fens should be at
least partially applicable to BSWs with histic
epipedons. Sites supporting dwarf trees (<3-m tall)
appear to have higher probabilities of being mires
than do sites supporting forest and woodland (Table
11), but Histosols can occur in forest and woodland
as well, at least as inclusions.
Table 11. Organic layer thickness and typical soils of Alaska Vegetation Classification (Level IV) classes
dominated by black spruce (Viereck et al. 1992:66,74,82,109,111).
Level IV Classification
Closed Black Spruce
Forest
Open Black Spruce
Forest
Black Spruce Woodland
Open Black Spruce
Dwarf Tree Scrub
Black Spruce Dwarf Tree
Woodland
Organic Layer Thickness (m)
Typical: 0.2
Maximum: 1 .0 (Sphagnum mounds)
Typical: 0.05 to 0.2 ("forest floor")1
Maximum: >1.0
Typical: 0.1 to 0.3
Minimum: 0.3
Minimum: 0.3
Soils
"well-drained alluvial gravels to
poorly drained Cryaquepts''
"Histic Pergelic Cryaquepts and
sometimes Cryochrepts"
"Cryaquepts or, more rarely,
Cryochrepts''
Histosols and Histic Pergelic
Cryaquepts?
Histosols and Histic Pergelic
Cryaquepts?
1. It is not clear that Viereck et al. (1992) mean "forest floor" to include all organic horizons.
Histic Pergelic Cryaquepts are stated to be the most frequent soils, which is at variance with
organic layers <0.2 m.
27
-------
m
Functional Profile of Black Spruce Wetlands in Alaska
VEGETATION
Characterization of BSWs in terms of specific
plant communities across northern North America is
difficult. Neither the United States nor the Canadian
wetland classification system (Appendix A) directly
uses specific plant communities as classification
units. Nevertheless, several approaches for charac-
terizing the vegetation of BSWs present themselves:
examine descriptions of classified wetlands to iden-
tify those supporting black spruce and evaluate black
spruce community types to identify their respective
probabilities of being wetlands.
Wetland Classes and Forms
Supporting Black Spruce
Black spruce wetlands primarily fall within the
Palustrine Forested Needle-leaved Evergreen and
Palustrine Scrub-Shrub Needle-leaved Evergreen
classes of the U.S. Fish and Wildlife Service classi-
fication system (Cowardin et al. 1979) and fre-
quently have saturated water regimes. Wetlands
dominated by cotton grass (Eriophorum spp.),
sedges, or other nonwoody vegetation, except
mosses or lichens, and supporting sparse (coverage
<30%) black spruce, can fall within the Palustrine
Emergent Wetland class. Emergent plants ("erect,
rooted, herbaceous, hydrophytes" [Cowardin et al.
1979:19]) often dominate fens, where mosses may
or may not be present, but Sphagnum mosses often
dominate ground cover in bogs. Little additional
general information about vegetation in BSWs can
be extracted from National Wetlands Inventory maps
or Cowardin et al. (1979).
The tolerance of black spruce for a variety of soil
moisture and trophic conditions allows the species to
appear in many plant communities. Some of these
communities occur in both wetland and nonwetland
settings, as well as in different wetland classes or
forms. Plant communities vary between different
types of bogs and fens across North America (Ap-
pendix B), but some taxa occur frequently (Table
12). Black spruce is more closely associated with
ombrotrophic than minerotrophic conditions but is
found in both types of mire.
Wetland Potential of Representative Black
Spruce Community Types in Alaska
Published descriptions of black spruce commu-
nity types provide some basis for inferring the prob-
ability that a particular type would be classified as a
wetland or nonwetland. Community type descrip-
tions providing species lists and densities or cover
percentages can be compared to the regional list of
wetland plants for Alaska (Reed 1988) to determine
(approximately) whether or not characteristic veg-
etation is hydrophytic. Similarly, descriptive infor-
mation on the presence or absence of permafrost and
physical characteristics of sites (e.g., slope, aspect,
Table 12. Frequently occurring genera and species in North American bogs and fens.
Stratum
Tree
Shrub
Herb
Ground
Cover
Bog Taxa
Black spruce, tamarack (sometimes)
Leatherleaf (Chamaedaphne calyculata),
Labrador-tea (Ledum spp.), laurel
(Kalmia latifolia), shrub birches, willow,
blueberry (Vaccinium spp.), and bog-
rosemary (Andromeda polifolia)
Cloudberry (Rubus chamaemorus),
cotton grass (sometimes)2
Sphagnum spp., lichens2
Fen Taxa
Tamarack, black spruce (sometimes)
Shrub birches, willow, sweetgale (Myrica gale),
bog-rosemary, bog kalmia (Kalmia polifolia),
buckthorn (Rhamnus alnifoliaf
Sedges, cotton grass, buckbean (Menyanthes
trifoliata), bladderwort (Utricularia spp.), arrow
grass (Triglochin maritima), bulrush (Scirpus spp.),
swamp horsetail (Equisetum fluviatile)3
Mosses (e.g., Drepanocladus revolvens,
Scorpidium scorpioides, Sphagnum spp.,
Tomenthypnum nitens)
1. Viereck and Little (1972:19), Glaser (1987), Larson (1991)
2. Zoltai, Taylor et al. (1988); Larson (1991)
3. Zoltai, Tarnocai et al. (1988); Zoltai, Taylor et al. (1988); Larson (1991)
22
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Black Spruce Wetlands
Table 13. Inferred probabilities that typical interior Alaska black spruce community types are jurisdictional
wetlands based on stand descriptions from Foote (1983:28-48).
Community Type
Picea marianal
Sphagnum spp.-Cladina
Picea marianal
Vaccinium uliginosum-
Ledum groenlandicuml
Pleurozium schreberi
Picea mariana-Betula
papyrifera/ Vaccinium
uliginosum-Ledum
groenlandicum
Picea marianal
Feathermoss-Lichen
Picea mariana-Picea
glauca/ Betula
glandulosa
Populus tremuloides-
Picea mariana/ Cornus
canadensis
Wetland Hydrology1
Yes: permafrost and
standing water present
Often: permafrost
generally present but
may be absent on south-
facing slopes
Sometimes: north-
facing slopes and valley
floors may have
permafrost
Sometimes: north-
facing slopes and valley
floors may have
permafrost
Unlikely: stony soils
prevent permafrost
probe, but thin organic
layer discourages
permafrost formation
Infrequent: permafrost
occurs only in pockets
Hydrophytic
Vegetation2
Yes: OBL species, bog
cranberry (Vaccinium
oxycoccos), and
Sphagnum mounds with
no FACU species
Yes: Equisetum
sylvaticum is the only
important FACU species
Yes: paper birch and
prickly rose (Rosa
acicularis) are the only
important FACU species
Yes: only one important
species, Geocaulon
lividum, is FACU
Yes: but two important
FACU species, white
spruce and prickly rose,
are present
Yes (marginal): OBL
species absent, FACU
species (quaking aspen,
prickly rose,
bunchberry) prominent,
only one important
FACW species (black
spruce)
Wetland Probability
High
High-to-moderate:
valley floors and north-
facing slopes high,
south-facing slopes low
probability
Moderate: valley floors
and north-facing slopes
high, south-facing slopes
low probability
Moderate: valley floors
and north-facing slopes
high, south-facing slopes
low probability
Moderate-to-low: well-
drained sites argue
against wetland
hydrology and hydric
soils
Low: well-drained sites
argue against wetland
hydrology and hydric
soils
1. Saturated soils assumed for sites with shallow permafrost.
2. Considering the three dominant species in each stratum, vegetation is hydrophytic under criteria used
for the National Wetlands Inventory if there is a predominance (>50%) of "obligate" (OBL) (>99%
estimated probability of occurring in wetlands), "facultative wetland" (FACW) (67-99% estimated
probability of occurring in wetlands), and "facultative" (FAC) (34-66% estimated probability of oc-
curring in wetlands) species (Reed 1988:9).
soil moisture) allows inferences about wetland hy-
drology and hydric soils. Table 13 presents such in-
ferences for six of many possible black spruce
community types of interior Alaska (Foote 1983:28-
48). Summary physical descriptions of these com-
munity types appear in Appendix C.
Uncertainty in the probability of various commu-
nity types being wetlands largely depends on site
slope and aspect. Slopes lacking permafrost are un-
likely to support wetland communities in the Inte-
rior. At least some east- and west-facing slopes may
be free of permafrost (Jorgenson and Kreig 1988),
but the bases of some south-facing slopes have per-
mafrost soils. Collins et al. (1988) found positive
mean annual soil temperatures on several slopes
with approximately southeast to south-southwest
aspects (131° to 202°).
Permafrost also can alter hydrology by raising
23
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Functional Profile of Black Spruce Wetlands in Alaska
land surfaces. Peat plateaus with raised surfaces
dominated by black spruce and lichens occur in
Yukon, Mackenzie (S.C. Zoltai, Can. For. Serv.,
pers. commun.), and Alaska (S.S. Talbot, U.S. Fish
Wildl. Serv., pers. commun.). These landforms have
organic soils (peat thickness >0.4 m) but might not
meet hydrologic criteria for wetlands. Site-specific
investigation may be necessary to delineate wetlands
within all but the wettest black spruce community
types.
ACTIVITIES POTENTIALLY AFFECTING
BLACK SPRUCE WETLANDS
Many activities associated with contemporary
society have the potential to affect BSWs. These
activities include filling, draining, flooding (wetland
conversion), or clearing; disposing of wastes; or
mining peat deposits. The following discussion out-
lines these activities in more detail.
Placement of Fill
Wetlands frequently are filled to provide stable
surfaces for transportation, building construction, or
resource development. Fill physically buries wet-
lands, radically changing their functions and values.
Secondary effects of fills include deposition of
chemical elements (particularly metals) in adjacent
wetlands by airborne dust from fill surfaces
(Santelmann and Gorham 1988) and alteration of
drainage patterns.
Transportation corridors in interior Alaska often
cross BSWs, although they may present particular
difficulties for construction. Besides highways, over-
burden disposal sites and fills for pipeline workpads
have been placed in BSWs (Pamplin 1979:50).
Commercial facilities such as warehouses and stor-
age yards require large areas of relatively low-cost
land, as does high-density residential housing. Black
spruce wetlands, especially those with minimal peat
depths, meet these requirements and can be filled to
provide a building surface. Commercial and residen-
tial development in BSWs has occurred in Anchor-
age, Fairbanks, and smaller communities in Alaska.
Mineral extraction, such as placer and hard rock
mining for gold, often requires stripping overburden
from the mineral-bearing material and piling it
somewhere on the mine site. Overburden and tail-
ings disposal sometimes occurs in BSWs. In the case
of oil and gas extraction, production wells and facili-
ties, and in some locations exploratory wells, occur
on gravel pads. At this time, most oil and gas explo-
ration and production in Alaska is in the tundra, but
future production may occur in BSWs.
Drainage
Wetlands frequently are drained to facilitate resi-
dential and commercial development, transportation,
agriculture, and forestry. Drainage effects include
lower water tables, accelerated peat decomposition,
and subsidence of ground surfaces (Verry and
Boelter 1979; Lugo, Brown et al. 1990). Even high-
way and other ditches largely ineffective for exten-
sive wetland drainage intercept lateral flow, dry out
downslope wetlands, and alter dominant vegetation
(Glaseretal. 1981).
Developers have drained BSWs in the Anchorage
area, usually in conjunction with fill placement
(Zenone 1976), and portions of those wetlands not
currently undergoing commercial and residential
development have been ditched in the past (e.g.,
Klatt Bog [Glass 1986a]). Farmers in Alaska drain
permafrost BSWs simply by stripping vegetation
and promoting thaw of permafrost that holds water
near the ground surface (Ping 1987, Ping et al.
1992). Agricultural drainage is a major cause of
wetland loss in the Lower 48 states (Tiner 1984:32)
and Europe (Taylor 1983, Baranovskiy 1991).
Ditches constructed to facilitate agriculture and
highway construction have damaged mires in Min-
nesota (Glaser 1987:67).
Foresters have drained European spruce and pine
forests (Putkisto 1980, Remrod 1980, Vasander
1984) and Canadian BSWs (Haavisto and Wearn
1987, Hillman 1987) to improve tree growth (Wang
et al. 1985, Dang and Lieffers 1989). Drainage can
allow earlier flowering (Lieffers and Rothwell
1987), reduce plant species diversity (Vasander
1984), and induce permafrost formation in fens
(Swanson and Rothwell 1986). Air temperatures
near ground level are expected to show greater ex-
tremes in drained wetlands, but this was not con-
firmed when tested in Alberta (Rothwell and Lieffers
1987).
Flooding
A variety of activities flood wetlands and convert
them to shallow or deep open-water habitats. Con-
version of one wetland form to another generally
24
-------
Black Spruce Wetlands
alters its functions. Whether such alterations are net
benefits or losses in terms of wetland values must be
determined by site-specific evaluations.
Mining impoundments will affect BSWs in the
Fairbanks area. On a smaller scale, linear wetland
fills such as access roads or highways block local
drainage and pond water, converting emergent wet-
lands to open-water habitats. Secondary impacts
such as flooding can equal or exceed the area of fill
placement (Walker et al. 1987). Secondary flooding
effects of linear structures in the taiga include
thermokarst development, altered vegetation, and
transition from bog to fen conditions (Pomeroy
1985).
Clearing and Harvest of Woody Vegetation
Removal of vegetative cover from wetlands al-
ters their character. Activities such as powerline in-
stallation (Grigal 1985) and maintenance, pipeline
construction, agricultural development, and logging
clear BSWs. Powerline construction and mainte-
nance can compact and rut peat surfaces (Glaser
1987:70, Magnusson and Stewart 1987), reduce
aerial biomass and species richness, cause erosion of
surface peat (Sims and Stewart 1981), and result in
herbicide use that adversely affects ericaceous veg-
etation and Sphagnum spp. (Magnusson and Stewart
1987). Clearing in permafrost terrain also can initiate
thermokarst features (Pewe 1982:35). Disturbance
associated with highway construction has been
linked to formation of small thermokarst ponds
(Senyk and Oswald 1983).
Logging for fuelwood and pulp occurs in BSWs.
Impacts other than removal of biomass include dis-
turbance of the peat surface by mechanized equip-
ment, which may lower carbon (C) to N ratios to
favor deciduous species (Brumelis and Carleton
1988, 1989); increased thaw depth in permafrost
soils (Evans et al. 1988); nutrient depletion (Gordon
1983); potential fragmentation of bird habitat (Haila
et al. 1987); potential for greater water yield and al-
tered water quality in logged basins, based on stud-
ies of upland spruce systems (Nicholson 1988); loss
of marten habitat (Snyder and Bissonette 1987);
potential reduction of invertebrate food items for
game birds (Stuen and Spids0 1988); elimination of
vegetative reproduction (Zasada 1986); and soil ero-
sion (Aldrich and Slaughter 1983, Tallis 1983).
These impacts may be positive or negative, depend-
ing on resource management objectives and values
placed on various wetland functions. In Alaska,
BSWs may be crossed by logging access roads, or
otherwise be affected by harvest activities, but they
currently are not targeted for harvest of wood
(Aldrich and Slaughter 1983). Emerging wood har-
vest and utilization technologies could change this
situation in the future.
Disposal of Waste
Society has often viewed wetlands as sites for
disposal of solid waste. Solid waste buries wetlands,
eliminating their functions and values, but has a sec-
ondary impact because landfill leachates contami-
nate ground water. A portion of Connors Bog in
Anchorage, Alaska, originally a Palustrine Scrub-
Shrub and Palustrine Emergent Wetland (Hogan and
Tande 1983:116), was landfilled from 1958 to 1977
and later developed as commercial property and ath-
letic playing fields (Glass 1986b). Similarly, the
landfill currently in use in Fairbanks, Alaska, is lo-
cated in an area of Palustrine Scrub-Shrub Wetland
supporting black spruce. Leachate from the Connors
Bog site is characterized by elevated levels of con-
ductivity, total organic compounds, dissolved solids,
and dissolved chloride; organic pollutants include
benzene, ethyl benzene, methylene chloride, toluene,
and dichloroethylene (Glass 1986i>).
Today, society explores wetlands as providing
final treatment and recycling mechanisms for sew-
age effluent and sludge (Stark and Brown 1988,
J0rgensen and Mitsch 1989, Ma and Yan 1989).
Peatlands used for wastewater disposal can maintain
their functions and values at low loading rates, but
impacts appear at high loadings. Wastewater impacts
at a Minnesota site included loss of black spruce
(Stark and Brown 1988). Wetlands receiving waste-
water discharges in Michigan and Wisconsin tended
to lose woody vegetation near the point of wastewa-
ter input and to develop extensive stands of cattail
(Typha spp.) and duckweed (Lemna spp.) (Kadlec
1987). Increased biomass and reduced species diver-
sity also characterize wetlands receiving wastewater
(Kadlec 1987).
Mining of Peat
Peat mining for fuel has a long history in Europe
and continues today (e.g., Taylor 1983). Large-scale
peat harvest for energy production has been studied
25
-------
m
Functional Profile of Black Spruce Wetlands in Alaska
in Minnesota, (Minn. Dep. Nat. Resour. 1984) but
currently is not viable (Glaser 1987:68). Peat mining
for horticultural purposes occurs on a small scale in
the United States (e.g., -567 ha in Minnesota
through 1981 [Minn. DNR 1981 in Glaser
1987:67]).
Peat mining alters wetland characteristics by
physical removal of vegetation, removal of organic
substrates, and alteration of hydrologic conditions
through drainage and reduced elevation of the land
surface (e.g., Clausen and Brooks 1983a). Runoff
from drained bogs chemically differs from runoff
from undisturbed bogs (Table 14). Moore (1987)
concluded that channelized and augmented runoff
from bog drainage could increase nutrient and dis-
solved organic C (DOC) loading of receiving waters.
Peat mining may remove peat down to mineral
soil or eutrophic peat may be left to support agricul-
tural uses (Taylor 1983). Recovery of mined
peatlands depends upon restoration of saturated con-
ditions favorable to growth of peat-forming vegeta-
tion. In situations where peat removal is not
complete and drainage ditches are blocked to retain
soiljnoisture, revegetation of mined terrain can oc-
cur (Glaser 1987:69). Shallow ponds left after min-
ing may be used by waterfowl.
RESEARCH
Scientists have not systematically studied the
functions and values of wetlands dominated by black
spruce, perhaps because research has focused on
commercially important upland stands. Even re-
search on a particular wetland type (e.g., palsa bog)
numbering black spruce as a component of its veg-
etation may not yield information applicable to other
wetland types supporting black spruce. Existing
studies shedding light on the functions of BSWs in-
clude silvicultural and ecologic research on black
Table 14. Water quality variables that have shown increased levels in run-
off from ditched or mined peatlands.
Variable
Water Temperature
Conductivity
Acidity
Suspended Solids
Fe
Na
Mg
K
Total Kjeldahl-N
Ammonia-N
Organic-N
Total Dissolved P
Dissolved Organic C
Location
Minnesota
Minnesota
Quebec
Minnesota
Minnesota
Minnesota
Quebec
Minnesota
Quebec
Quebec
Quebec
Minnesota
Minnesota
Quebec
Minnesota
Quebec
Quebec
Source
Clausen and Brooks (1983a)
Clausen and Brooks (1983a)
Moore (1987)
Clausen and Brooks (1983a)
Clausen and Brooks (1983a)
Clausen and Brooks (1983a)
Moore (1987)
Clausen and Brooks (1983a)
Moore (1987)
Moore (1987)
Moore (1987)
Clausen and Brooks (1983a)
Clausen and Brooks (1983a)
Moore (1987)
Clausen and Brooks (1983a)
Moore (1987)
Bourbonniere (1987), Moore (1987)
26
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Black Spruce Wetlands
spruce forests and treeless mires, research in indi-
vidual disciplines (e.g., hydrology) related to wet-
land functions, and directed research on wetland
functions conducted in areas outside the distribution
of black spruce. The following discussion outlines
sources of information used in compiling this pro-
file. Relevant citations appear elsewhere in the text.
Forestry Studies
Silvicultural research related to black spruce has
focused on methods to improve timber production
and promote regeneration following harvest. Be-
cause black spruce occurs on wet, lowland sites as
well as in upland terrain, foresters and researchers
have drained and fertilized forest soils to improve
tree growth. The response of black spruce to these
treatments provides information on nutrient deficien-
cies in treed wetlands and the ecologic tolerances of
black spruce. This information, in turn, allows infer-
ences about the ability of forested wetlands to use or
immobilize nutrients, which is relevant to their wa-
ter quality functions.
Foresters have studied harvest strategies and sur-
face treatments to promote regeneration of logged
stands. Clearcutting, strip cutting, and selective cut-
ting are used for timber harvest in Canada. Pre-
scribed burning, mechanical disturbance, and
planting influence forest regeneration and stand
composition. The response of black spruce to these
silvicultural treatments reflects its biology and rela-
tionships with other species.
Ecologic Studies
Scientists have studied the structure and function
of taiga ecosystems, including nutrient cycling, soil
temperature, and fire. Some of the black spruce
stands used as study areas in these research projects
are wetlands. Wetland functions may be inferred
from research findings concerning such stands and
from an understanding of the controls on black
spruce ecosystems.
Research shows that floodplain processes and
fire are principal causes of primary and secondary
succession in taiga ecosystems of interior Alaska.
Successional changes affect soil temperature and
moisture, as well as wildlife habitat. Relationships
between soil moisture and plant communities relate
to hydrologic functions, nutrient cycles provide in-
formation applicable to water quality functions, and
synecologic research illuminates the trophic and
habitat functions of ecosystems. Ecologic studies of
individual species and groups of species in interior
Alaska, northern Canada, and elsewhere also pro-
vide information on the habitat function of BSWs.
Research on treeless mires in Canada, the Great
Lakes Region of the Lower 48 states, and Europe,
including studies of their paleoecology, successional
patterns, permafrost features, and response to distur-
bance, provides information on the relationships of
treed and treeless wetlands and shifts between these
forms. Understanding these relationships helps ex-
trapolate information on treeless mires to BSWs.
Studies of the vegetation, geomorphology, and clas-
sification of treeless mires in Alaska are few, how-
ever.
Physical Studies
Very little physical science research in Alaska
and northern Canada directly examines the functions
of BSWs, but hydrologic, permafrost, and water
quality (including water chemistry) studies con-
ducted in watersheds containing such wetlands pro-
vide information that can be synthesized to
characterize these functions. Alaska hydrologic stud-
ies that identify specific wetland types, such as per-
mafrost catchments dominated by black spruce, may
be viewed as functional in nature. Water quality re-
search in Alaska has addressed wetland responses to
nutrient enrichment, evaluated the water quality
function of mires in the Anchorage area, and com-
pared water quality in permafrost-free and perma-
frost-dominated watersheds in the Interior.
Additional information on the hydrologic and water
quality functions of BSWs can be found in studies
conducted outside Alaska.
Current Knowledge
Studies of treed and treeless bogs and fens largely
have focused on their hydrology, soil and water
chemistry, and vegetation. The origin and flow of
water through these mires strongly influence their
chemistry and thus their plant communities. Decom-
posing plants accumulate in mires as peat, which can
alter mire hydrology with concomitant changes in
chemistry and vegetation. Long-term climatic
changes, short-term natural disturbances such as fire,
and human-induced impacts influence mire charac-
teristics and can produce cyclic excursions in mire
27
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Functional Profile of Black Spruce Wetlands in Alaska
ecology. Mires often do not follow traditional
hydroseral successional pathways.
European and Siberian studies of mires often em-
phasize wetland classification and description of
vegetation. Other palearctic studies address mire
stratigraphy, uses, values, and impacts. Canadian re-
searchers have documented the stratigraphy, mor-
phology, and vegetation of taiga mires, including the
role of permafrost, but these investigations, like
those of Europe and northern Asia, usually do not
directly address wetland functions. The peatlands of
glacial Lake Agassiz and other areas in northern
Minnesota are particularly well-studied. Black
spruce and tamarack dominate many wetlands in this
region. Similarities among physical, chemical, and
biological characteristics of circumpolar taiga
peatlands allows inferences about the functions of
Alaska's BSWs.
Few comprehensive studies of interior Alaska's
BSWs exist. An early report described "bog" [tree-
less mire] vegetation and postulated cycles between
treed and treeless wetlands. Later investigations de-
scribed the vegetation of treeless taiga wetlands, for-
est community types that include BSWs, and the
hydrology of permafrost basins supporting black
spruce. Most Alaska research has not directly ad-
dressed the functions of BSWs and has not been
multidisciplinary in nature.
In summary, integrated knowledge of BSWs in
Alaska is sparse, but lines of evidence from a vari-
ety of locations and disciplines are available in the
literature. Synthesis and analysis of this evidence
yields a coherent picture of the wetland functions of
these wetlands. This picture points the way to further
research to fill data gaps.
28
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HYDROLOGIC FUNCTIONS
Wetlands interact with the hydrologic cycle
(Odum 1979). These interactions comprise the hy-
drologic functions of wetlands: groundwater re-
charge and discharge, flow regulation, and erosion
control (Sather and Smith 1984:3-10). In Alaska,
permafrost can modify wetland hydrology. This
chapter addresses hydrologic functions of BSWs and
identifies topics for further research.
GROUNDWATER DISCHARGE
Wetlands often discharge groundwater (Carter et
al. 1979). Groundwater discharge can seep from an
unconfined aquifer or flow from a confined (arte-
sian) aquifer that intersects the ground surface. Per-
mafrost can provide aquifer confinement (Kane and
Stein 1983). Groundwater discharge is a wetland
function that stabilizes water levels and facilitates
ecologic processes such as fish spawning (Adamus
and Stockwell 1983:7, Larson et al. 1988), rearing,
and overwintering.
Where either continuous or discontinuous perma-
frost is present, the perennially frozen layer separates
groundwater into suprapermafrost and
subpermafrost zones (Kane and Stein 1983).
Suprapermafrost groundwater occupies the satu-
rated portion of the active layer; subpermafrost
groundwater lies beneath the perennially frozen
layer. Taliks, thawed zones within permafrost
(Gabriel andTalbot 1984:112), often occur beneath
waterbodies. Taliks can penetrate the permafrost
layer and allow hydrologic connections between
suprapermafrost and subpermafrost zones (Woo
1986).
Suprapermafrost Groundwater
Active layers of BSWs having saturated organic
soils underlain by permafrost can act as shallow un-
confined aquifers (Slaughter and Kane 1979). Verti-
cal infiltration rates are high (e.g., 2.18 mm-s'1),
making overland flow unlikely (Dingman 1971:37,
1973). Dry bulk density of surface organics is low
(0.02-0.04 g-cnr3), increasing to 1.45 g-cnr3 at the
interface of organic and mineral soil (Slaughter and
Kane 1979).
Snowmelt and rainfall rapidly enter the organic
layer, but high-moisture permafrost prevents deep
penetration into mineral soil (Kane 1980, Kane and
Stein 1983). Consequently, suprapermafrost ground-
water flows downslope within thawed organic soils
and, at a much lower rate, within thawed mineral
soils (Dingman 1973; Slaughter and Kane 1979; D.
L. Kane, Univ. Alaska, pers. commun.). Substantial
flow occurs in the organic layer during snowmelt on
permafrost slopes (Kane et al. 1978). Flow within
the organic layer following rainfall depends upon
antecedent moisture conditions, and the ratio of run-
off to rainfall increases with wetness of the water-
shed (Dingman 1973).
The hydrologic characteristics of permafrost
slopes supporting BSWs in interior Alaska are simi-
lar in some respects to those of bogs. Precipitation
infiltrates thick organic layers with little or no over-
land flow, lateral hydraulic conductivity exceeds ver-
tical conductivity, and slope surfaces are
ombrotrophic. Ombrotrophic BSWs do not receive
groundwater and thus do not perform the groundwa-
ter-discharge function.
Black spruce also occurs in minerotrophic wet-
lands. Suprapermafrost groundwater discharging at
the bases of bog-like slopes (e.g., Dingman 1973)
probably becomes somewhat minerotrophic during
downslope passage because seasonal thaw on slopes
29
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Functional Profile of Black Spruce Wetlands in Alaska
nearly always reaches the interface between organic
and mineral soil (D. L. Kane, Univ. Alaska, pers.
commun.). Where the water table approaches the
surface, groundwater influences vegetation through
often parallel gradients of increasingly
minerotrophic and hydric conditions (e.g., Vitt and
Slack 1975, Calmes 1976:62, Jasieniuk and Johnson
1982).
Black spruce wetlands receiving suprapermafrost
groundwater on valley floors appear to be
minerotrophic. For example, shrub/sedge tussock
vegetation (with variable amounts of black spruce
and tamarack) on a valley floor of interior Alaska
contrasts with black spruce/moss vegetation on the
adjacent permafrost slope (Dingman 1971:29-31).
The similar sedge tussock (i.e., Eriophorum
vaginatum) community type is minerotrophic at sites
near Fairbanks (Calmes 1976:47-48).
Black spruce wetlands supplied by discharge of
suprapermafrost groundwater perform the ground-
water-discharge function, albeit on a scale limited by
the small storage capacity of the shallow active layer
on up-gradient permafrost slopes. Suprapermafrost
groundwater discharges for long recession periods
following precipitation in permafrost basins, but es-
sentially ceases during dry periods (Dingman 1973).
Such discharges are short-term phenomena com-
pared with groundwater discharges that can provide
year-round baseflows in nonpermafrost areas.
Subpermafrost Groundwater
Vertical and horizontal circulation of groundwa-
ter can maintain taliks within permafrost (Hopkins et
al. 1955) and allow discharge of subpermafrost
groundwater at the surface. Examples include peren-
nial springs in peatlands on alluvial and glaciofluvial
fans (van Everdingen 1988), a mire lake fed by
groundwater discharge (Kane and Slaughter 1973),
and interior Alaska streams fed by springs (Kane et
al. 1973). Discharge of subpermafrost groundwater
to stream channels is not directly relevant to the
functions of BSWs, although such wetlands may
dominate the landscape within which the discharge
occurs.
In contrast, discharge of subpermafrost ground-
water to lakes, ponds, or flowages can supply fens
located adjacent to, or covering the surface of, these
waterbodies on grounded or floating peat mats (e.g.,
Kane and Slaughter 1973, Calmes 1976, Racine and
Walters 1991). If black spruce is present, such fens
are BSWs that perform the groundwater-discharge
function, but this function cannot be extrapolated to
all fens or to other BSWs. Laterally continuous per-
mafrost immediately rules out discharge of
subpermafrost groundwater. Hydrologic information
(e.g., piezometer or water balance studies) or possi-
bly topographic analysis (e.g., mire-dominated basin
with no inlet but with an outlet), coupled with the
presence of thawed soils, is necessary to show that
discharge of subpermafrost groundwater is occurring
in a given BSW.
Groundwater Discharge in Unfrozen Terrain
Southern Alaska largely is free of permafrost,
which removes an impediment to groundwater dis-
charge, but most pertinent studies in unfrozen terrain
have occurred outside Alaska. Groundwater dis-
charge has been documented in swamps (Roulet
1991, Woo and Valverde 1981), a cattail marsh
(Gehrels and Mulamoottil 1990), an Alaska mire
lake (DOWL Eng. 1983), a spruce-tamarack fen
(Brown and Stark 1989), and spring fens
(Almendingeretal. 1986; Zoltai, Taylor etal. 1988),
and basin wetlands may penetrate regional water
tables (Boelter and Verry 1977). Fens with large
flows and deep water do not support trees, but black
spruce can occur in tamarack and spring fens
(Boelter and Verry 1977).
The spruce-tamarack fen studied by Brown and
Stark (1989) showed strong, upward groundwater
head gradients with diffuse groundwater discharge
so that the entire fen performed the groundwater-dis-
charge function. In contrast, spring fens (Appendix
B) of Canada's Boreal Wetland Region are linear
features continuously supplied by groundwater from
point sources (Zoltai, Taylor et al. 1988). Treed "is-
lands," which support black spruce (S.C. Zoltai,
Can. For. Serv., pers. commun.), can occur in less
minerotrophic areas of Canadian spring fens (Zoltai,
Taylor et al. 1988) but presumably are not sites of
groundwater discharge. Both types of fen may occur
in Alaska but have not been specifically described
for this location.
Bogs and spring fens in the form of unfrozen peat
mounds that support black spruce occur in northern
Minnesota, but BSWs with these characteristics have
not been described in Alaska. Black spruce bogs, by
definition, do not perform the groundwater-dis-
30
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Hydrologic Functions
charge function. Treeless, ombrotrophic bog aprons
or Sphagnum lawns surrounding forested bogs
merge downslope into poor fen water tracks that
channel minerotrophic runoff (Glaser 1987:24-34).
Weakly minerotrophic lower bog aprons indicate
either groundwater discharge (Siegel 1983) or the
effects of peat decomposition (Glaser et al. 1981).
Discharge from highly permeable surface organics
(i.e., the acrotelm or aerobic, partly living upper
layer of mires [Ingram 1983]) of a bog would be lim-
ited in volume, perhaps somewhat akin to discharge
of suprapermafrost groundwater in northern regions.
Current research in the northern Minnesota
peatlands indicates a drought-affected interplay be-
tween precipitation-driven water table domes under
raised bogs and upward head gradients driven by
regional groundwater (Siegel and Glaser 1987,
McNamara et al. 1992, Siegel et al. 1995). Upward
head gradients of sufficient duration and magnitude
to frequently discharge groundwater at the surface of
raised bogs would change them to fens. Spring fen
mounds (Almendinger et al. 1986) and fen water
tracks at least periodically discharge groundwater
(Siegel and Glaser 1987) and thus perform the
groundwater-discharge function.
In southern Alaska, groundwater discharges to
Mosquito Lake in Anchorage (DOWL Engineers
1983) but apparently does not discharge to the BSW
to the northeast, which slopes toward the lake.
Groundwater also moves through peat deposits of
Klatt Bog in Anchorage but apparently does not dis-
charge to the undisturbed bog surface (Glass 1986a).
Nearby Connors Bog is largely supplied by precipi-
tation, but groundwater occasionally discharges to,
or passes through, Connors Lake (Glass 1987fc). The
sedge fen occupying exposed lake bottom along the
northwest shoreline of Connors Lake (Hogan and
Tande 1983:29-32) could intermittently discharge
groundwater, but there is no evidence that adjacent
black spruce stands do so. Although detailed infor-
mation is not available, black spruce stands in the
Anchorage "bogs" may be ombrotrophic and thus
not capable of performing the groundwater-dis-
charge function.
Functional Summary
Many Alaska wetlands are ombrotrophic,
unaffected by groundwater. Ombrotrophic BSWs,
including bogs, do not perform the groundwater-dis-
charge function. Groundwater discharge or surface
runoff from mineral terrain influences minerotrophic
wetlands, including fens. Black spruce (or tamarack)
wetlands perform the groundwater-discharge func-
tion when they are supplied by upward groundwater
flow, but the distribution and frequency of this phe-
nomenon in Alaska are not known.
Site-specific documentation of groundwater dis-
charge is required to ascribe the groundwater-dis-
charge function to any particular minerotrophic
BSW. Exposure of a suprapermafrost water table at
the base of a moss-covered permafrost slope, evi-
dence of a talik in terrain where permafrost can form
a confined aquifer, a visually-apparent spring, a
water balance study indicating groundwater dis-
charge, or a piezometric study showing upward
groundwater flow can provide such documentation.
Water chemistry is another potential indicator of
the strength of the groundwater-discharge function
for a given fen or fen-like wetland. Presumably,
groundwater discharge dominates a rich fen to a
greater degree than it does a poor fen when the same
aquifer supplies both fens (i.e., Ca concentration and
pH of the discharge is the same in both fens). Such
comparisons are not valid between fens with differ-
ent discharge sources because calcareous aquifers
produce higher Ca and pH concentrations than do
mineral-poor aquifers.
Functional Sensitivity to Impacts
The groundwater-discharge function of
minerotrophic BSWs is impaired or eliminated by
fill placement within the area of discharge. Poorly
permeable fill (e.g., silt, clay) and compaction of
underlying substrates reduce the hydraulic conduc-
tivity of the groundwater "window" through which
discharge occurs. Fill outside the zone of groundwa-
ter discharge, and not otherwise impairing flow
within the aquifer, is unlikely to directly affect dis-
charge but might alter patterns of surface flow and
affect down-gradient ecologic communities and
water supplies. Lower hydraulic conductivities,
coupled with reduced areas available for discharge,
imply decreased rates of groundwater discharge in
filled wetlands.
Mitigating the impact of fill on groundwater dis-
charge might be possible in nonpermafrost terrain.
Considering only the narrow "water-supply" aspect
of groundwater discharge, a fill of shot rock (highly
31
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Functional Profile of Black Spruce Wetlands in Alaska
permeable) or placement of perforated drains in a
gravel bed beneath less permeable fill might permit
lateral flow, which could continue to supply remain-
ing wetlands or streamflow. Drains of this sort usu-
ally freeze and fail when placed on permafrost soils,
however (D. L. Kane, Univ. Alaska, pers. commun.).
Wetland drainage is unlikely to adversely affect
the water-supply aspect of the groundwater-dis-
charge function of minerotrophic BSWs. Ditches or
tiles that intercept groundwater and direct it to the
same drainages that originally received such flows
would maintain or increase downstream water-sup-
ply uses. Redirection of flow could alter downstream
water supplies, however.
GROUNDWATER RECHARGE
Surface water infiltrates the ground to recharge
aquifers. Although some wetlands, particularly those
only seasonally holding water, may recharge ground-
water, many wetlands apparently do not perform this
function (Carter et al. 1979, Sather and Smith
1984:6). Black spruce wetlands share the variability
of other wetlands with respect to the groundwater-
recharge function.
The catotelm, highly-decomposed, anaerobic
peat of low hydraulic conductivity, underlies the
acrotelm (Ingram 1983). Thick deposits of peat
therefore may perch bog water tables above regional
water tables (e.g., Bay 1969) with flow (primarily
lateral) limited to the acrotelm (Glaser 1987:18). Al-
ternatively, downward head gradients imply that
bogs recharge regional groundwater (Siegel 1983,
Glaser 1987:20). Both views imply that bogs are
sites of groundwater recharge, either of shallow,
perched water tables or of regional water tables.
Ombrotrophic BSWs should exhibit similar charac-
teristics.
Fens vary in their capability to recharge ground-
water. Groundwater discharge within a fen demon-
strates a hydraulic connection to an aquifer and thus
a potential for recharge in response to regional
groundwater fluctuations (Glaser 1987:20). Fens that
continually discharge groundwater (e.g., spring fens)
do not perform the groundwater-recharge function.
Fens fed primarily by surface flow could be under-
lain by soils of low permeability, which would re-
duce their potential for recharging groundwater. The
variable recharge characteristics of fens require site-
specific studies to document this hydrologic func-
tion. Minerotrophic BSWs should be comparable to
fens with respect to groundwater recharge.
Suprapermafrost Groundwater
-Shallow permafrost frequently characterizes bogs
(e.g., Zoltai, Tarnocai et al. 1988) and other
ombrotrophic wetlands within the region of discon-
tinuous permafrost. Infiltration of precipitation re-
charges suprapermafrost groundwater (Williams and
Waller 1963) as demonstrated by the following evi-
dence: snowmelt satisfies the moisture deficit of the
organic layer before significant runoff is initiated
(Kane et al. 1981), near-surface flow occurs within
the organic layer (Kane et al. 1978), rainfall intensity
and duration control moisture retention of moss
(Chacho and Bredthauer 1983), and streams in per-
mafrost watersheds exhibit long recession periods
following rainfall, probably due to suprapermafrost
subsurface flow (Dingman 1971:80). Supra-perma-
frost groundwater provides insufficient volume for
direct domestic water supply, although it does con-
tribute water to waterbodies providing such supplies
(Kane and Stein 1983). Permafrost BSWs perform
the groundwater-recharge function, but only with
respect to suprapermafrost groundwater.
Subpermafrost Groundwater
Many minerotrophic wetlands in the zone of dis-
continuous permafrost are underlain by permafrost
(Calmes 1976; D. K. Swanson, Nat. Resour.
Conserv. Serv., pers. commun.) and cannot recharge
subpermafrost groundwater. Other minerotrophic
wetlands, such as northern ribbed fens in the Hudson
Bay Lowlands, Labrador, and Great Slave Lake Re-
gion, usually do not contain permafrost (P. H. Glaser,
Univ. Minn., pers. commun.). Elsewhere, permafrost
may be limited to specific geomorphic features such
as the peat ridges of ribbed fens (Zoltai, Tarnocai et
al. 1988). Thawed, minerotrophic BSWs might re-
charge subpermafrost groundwater if head gradients
periodically were directed downward, but such re-
charge has not been demonstrated in Alaska.
Most recharge of subpermafrost groundwater in
interior Alaska occurs in unfrozen uplands such as
south-facing slopes (Kane and Stein 1983) and, for
alluvial aquifers, by infiltration from larger rivers
(Nelson 1978:16). The primary source of recharge in
uplands is infiltration of snowmelt (Kane et al. 1978,
Kane 1980, Kane et al. 1981, Kane and Stein 1983,
32
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Hydrologic Functions
Gieck and Kane 1986). Black spruce wetlands gen-
erally should not be viewed as sites of recharge for
subpermafrost groundwater without site-specific pi-
ezometric or water-balance studies.
Groundwater Recharge in Unfrozen Terrain
Permafrost becomes widely scattered in the
southerly portions of the zone of discontinuous per-
mafrost (Brown and Pewe 1973). In this region, sea-
sonally frozen soils may affect infiltration and thus
recharge of groundwater (Dingman 1975:40-43) but
often have no effect where dry soils have the capac-
ity to take up more moisture than snowmelt provides
(D. L. Kane, Univ. Alaska, pers. commun.). Some
wetlands recharge groundwater in unfrozen terrain.
A swamp (Woo and Valverde 1981) and a cattail
marsh (Gehrels and Mulamoottil 1990) recharged
groundwater in Ontario, although other portions of
these wetlands discharged groundwater and ex-
changes probably were confined to thick organic lay-
ers. Black spruce bogs and fens on organo-karst
terrain in the Hudson Bay Lowlands recharged
groundwater via sinkhole complexes (Cowell 1983).
In Minnesota, a basin bog with deep peat and a
perched water table recharged groundwater to a lim-
ited extent by lateral flow through surficial peat to
surrounding glacial till, and a peat bog with shallow
peat exhibited vertical recharge to underlying and
surrounding sand, but a fen did not recharge ground-
water (Verry and Boelter 1979). Although poor fen
water tracks occasionally can recharge groundwater
(e.g., Siegel and Glaser 1987), site-specific hydro-
logic studies are required to demonstrate this func-
tion.
An unconfined aquifer of peat interbedded with
gravel and sand lenses over clay and silt occurs in
Anchorage, Alaska (Zenone 1976). Precipitation
supplies most of the water to the aquifer in Klatt
Bog, but percolation to the underlying, confined
aquifers probably is much less than evapotranspira-
tion losses (Glass 1986a). The unconfined aquifer of
nearby Connors Bog transferred only an estimated
10 mm-yr1 to the underlying confined aquifer (Glass
1986&). Ombrotrophic BSWs recharge groundwater
in unfrozen terrain, but the magnitude of such re-
charge may be small.
Functional Summary
Ombrotrophic BSWs perform the groundwater-
recharge function, but the magnitude of recharge
generally is small. In regions of widespread discon-
tinuous permafrost, Ombrotrophic wetlands recharge
only suprapermafrost groundwater. Where perma-
frost is absent, Ombrotrophic wetlands recharge ei-
ther shallow, perched water tables or deeper regional
aquifers. In either case, vertical flow through deep
layers of sapric (highly decomposed) peat may be
small. Uplands and some riparian areas contribute
more to regional groundwater recharge than do
Ombrotrophic wetlands. Minerotrophic BSWs
should not be considered to perform the groundwa-
ter-recharge function unless site-specific piezomet-
ric or water-balance studies show that recharge
occurs.
The trophic status of a BSW can indicate its po-
tential for groundwater recharge: ombrotrophy indi-
cates recharge whereas, in the absence of obvious
surface inputs of Ca-rich water, strong minerotrophy
indicates discharge. Weak minerotrophy is not an
indicator for or against recharge because poor fens
can arise from discharge of mineral-poor groundwa-
ter (Vitt et al. 1975 in Zoltai 1988), oxidative decom-
position of peat in areas of concentrated flow (Glaser
et al. 1981), and, possibly, fluctuating head gradients
with occasional recharge (Glaser 1987:20). Later-
ally-extensive permafrost in a BSW indicates that
the groundwater-recharge function, if present, is lim-
ited to suprapermafrost groundwater whereas
thawed areas indicate potential recharge of
subpermafrost groundwater.
Functional Sensitivity to Impacts
The groundwater-recharge function of BSWs is
sensitive to fill placement. Compacted fill and under-
lying compressed peat have lower hydraulic conduc-
tivities than do the highly-permeable fibric peats
(undecomposed) of undisturbed wetlands and thus
would resist infiltration and percolation of precipita-
tion. Fill runoff might flow to surface drainages
rather than enter the groundwater system. Directing
fill runoff to adjacent undisturbed wetlands capable
of recharging groundwater could compensate for lost
recharge area, if runoff loading of the remaining
wetlands did not exceed their infiltration capacity.
Siltation from fill surfaces could impair the ability of
remaining wetlands to recharge groundwater, how-
ever.
The groundwater-recharge function of BSWs is
33
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Functional Profile of Black Spruce Wetlands in Alaska
sensitive to drainage. Drainage converts groundwa-
ter flow to surface flow, shortening groundwater
flow paths and reducing groundwater volumes po-
tentially available for recharge. In wetlands having
only near-surface groundwater (e.g., permafrost
wetlands), drainage affects small volumes of water
of localized significance. The adverse effect of
drainage on recharge potentially is greatest for un-
frozen BSWs that supply regional water tables, but
studies reviewed for this profile did not demonstrate
large recharge volumes for these wetlands.
The detrimental effect of drainage on groundwa-
ter recharge is ameliorated by the relatively low hy-
draulic conductivity of sapric peat. Effective
drainage requires closely spaced ditches, as little as
30 to 40 m apart (Glass 1986a, Lieffers and
Rothwell 1987). Boelter(1972 in Glaseret. al. 1981)
found that even a deep ditch drained only the surface
layer of peat at horizontal distances exceeding 5 m.
Effective drainage of BSWs, therefore, is an expen-
sive proposition, which could limit its application.
FLOW REGULATION
Flow regulation, sometimes referred to as flood
control, occurs when wetlands interact with precipi-
tation, surface runoff, and streamflow to modify the
magnitude, timing, and duration of downstream
flows (Carter et al. 1979, Sather and Smith 1984:3-
5, Larson et al. 1988). Wetlands store precipitation in
several ways: snowmelt and rainfall percolate into
the soil, water fills surface depressions, and basin
topography temporarily detains flow. Wetland veg-
etation reduces water velocity by increasing channel
roughness (i.e., Manning's "n") (Carter et al. 1979),
and evapotranspiration of stored surface water and
groundwater reduces downstream flows (Larson et
al. 1988). "Relative to inputs, wetland basins lose
less water through runoff and more through evapo-
ration than non-wetland basins under similar envi-
ronmental conditions" (Roulet 1987:338). Wetlands
potentially provide baseflows to streams but gener-
ally are less effective than upland areas because
wetlands have high evapotranspiration losses (Carter
etal. 1979).
Black spruce wetlands are heterogeneous with re-
spect to flow regulation and differ with respect to
storage capacities for precipitation and surface
flows, proportions of stored water subsequently re-
leased to surface and subsurface flows, and time
scales over which releases occur. Permafrost, sea-
sonal frost, and high water tables limit the storage
capacities of these wetlands and change the runoff
responses of associated watersheds.
Subsurface Storage of Precipitation
High snowmelt runoff characterizes permafrost
sites (Woo 1986, Roulet 1987); nevertheless, BSWs
store snowmelt within the soil system. During win-
ter, soil moisture moves into the overlying snowpack
and desiccates the organic layer in response to tem-
perature-driven vapor-pressure gradients (Slaughter
and Kane 1979, Kane et al. 1981, Slaughter and
Benson 1986, Woo 1986). The desiccated organic
layer has low bulk density (Slaughter and Kane
1979) and accepts initial snowmelt (Kane et al.
1981), although runoff begins before the moisture
deficit of the organic layer is completely satisfied
(Chacho and Bredthauer 1983).
The water-holding capacity of the desiccated or-
ganic layer limits snowmelt water storage in perma-
frost wetlands because snowmelt generally cannot
readily enter underlying high-moisture mineral soils.
In these soils, water migrates toward the freezing
front and forms a relatively impermeable ice-rich
layer during freeze-up; this layer later inhibits snow-
melt percolation during breakup (Kane 1980, Kane
et al. 1981, Kane and Stein 1983). In contrast, dry,
frozen mineral soils characteristic of permafrost-free
uplands infiltrate snowmelt and produce little runoff
(Kane 1980, Kane et al. 1981, Kane and Stein 1983).
Snowmelt infiltration on nonpermafrost uplands
greatly exceeds that in permafrost BSWs in interior
Alaska.
Unfrozen BSWs also accept only limited snow-
melt. Examples include seasonally-frozen wetlands
(presumably peatlands) near James Bay, Canada,
which have "wetland" streamflow regimes charac-
terized by low infiltration into frozen ground and
high snowmelt flows (Woo 1988); black spruce bogs
in Minnesota, which have high water tables (Bay
1969, Verry and Boelter 1979); and fens, which also
have high water tables (Verry and Boelter 1979,
Glaser 1987:21). Similarly, high spring flows char-
acterized Wisconsin basins with high proportions of
wetlands and lakes (not differentiated) as compared
to basins with no wetlands and lakes (Novitzki
1979). As in permafrost BSWs, snowmelt storage in
seasonally-frozen wetlands appears small.
34
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Hydrologic Functions
Black spruce wetlands more easily store water
during summer, when frost and water tables are de-
pressed, than during spring, when frost and water
tables are high. Active layer thickness increases ap-
proximately linearly from May to September on
undisturbed, forested, permafrost sites in interior
Alaska and reaches a maximum in September or
early October (e.g., Viereck 1982). The unsaturated
portion of the active layer can accept precipitation
until the water table reaches the surface, at which
time overland flow occurs (Wright 1979, Woo
1986). In interior Alaska, precipitation quickly in-
duced overland flow on a minerotrophic permafrost
valley bottom with a high water table (Dingman
1973). Storage in permafrost BSWs is limited to the
capacity of the active layer, which in summer is de-
pendent upon depth of thaw (Woo 1986), antecedent
moisture (Roulet 1987), groundwater flow, and
evapotranspiration.
As in permafrost wetlands, rainfall infiltration
can occur in nonpermafrost BSWs until the zone of
saturation reaches the surface. Unsaturated peat
thickfiess was <0.3 m after snowmelt, generally did
not exceed 0.9 m at any time during 1983, and at one
undisturbed location was -0.2 m even in mid-sum-
mer for Klatt Bog in Anchorage, Alaska (Glass
1986a). Forested swamps that recharge groundwater
(Woo and Valverde 1981) and discharge only a frac-
tion of incident precipitation (Rouletl991), and fens
with reversing groundwater head gradients
(Almendinger et al. 1986, Siegel and Glaser 1987),
imply that treed fens should store rainfall when wa-
ter tables are below the surface. In contrast, floating-
mat, treeless groundwater-discharge fens of interior
Alaska (Racine and Walters 1991) intercept rainfall,
but storage time within the mat should be negligible.
Water fluxes across the surfaces of ombrotrophic
wetlands are downward whereas surfaces of
minerotrophic wetlands receive upward or horizon-
tal flows. Based on these characteristics,
ombrotrophic BSWs likely infiltrate and store more
rainfall than do minerotrophic BSWs. Water table
position controls storage in both trophic classes,
however.
Detention and Depression Storage
of Precipitation
The topography and microtopography of peat-
forming wetlands provide surface storage of snow-
melt and rainfall and slow overland flow. On perma-
frost slopes, water fills microtopographic depres-
sions as depression storage before runoff occurs
(Woo 1986). Depressions filled to a depth greater
than the elevation of the surface outlet moderate
flow by providing detention storage (Woo 1986).
Pits excavated in a permafrost slope quickly flooded
with snowmelt (Kane et al. 1978), illustrating the po-
tential for depression and detention storage by
microtopographic features in BSWs.
Black spruce wetlands with slightly sloping sur-
faces also store water in surface depressions. Such
depressions include the crescentic pools of domed
bogs, "small wet depressions" of northern plateau
bogs,flarks (wet depressions) separated by strings
(peat ridges oriented transverse to the direction of
flow) of northern ribbed fens, and entire collapse
scar bogs and fens (Natl. Wetlands Working Group
1988:417-420). Microtopographic depressions in
discontinuous permafrost terrain in Quebec stored
44 to 74% of total snowmelt runoff (FitzGibbon and
Dunne 1981). The thaw ponds, depressions, and
mounds of wet, ombrotrophic black spruce commu-
nities (Foote 1983:47) and the intertussock hollows
of minerotrophic black spruce communities (D. K.
Swanson, Nat. Resour. Conserv. Serv., pers.
commun.) suggest modest depression and detention
storage by BSWs of interior Alaska. Water table
position (e.g., Bay 1969) and microtopography de-
termine the volume available for surface storage in
BSWs.
Release of Stored Precipitation
and Effect on Stream/low
Water storage and release by BSWs affect
streamflow. Partitioning of released water between
surface and subsurface flows and evapotranspiration
changes seasonally. Permafrost black spruce slopes
release suprapermafrost groundwater during snow-
melt. In an interior Alaska watershed, such slopes
released ~51 % of snowmelt, with the remainder re-
tained within saturated organic soils of the active
layer (Kane et al. 1981). Although the organic layer
delayed runoff initiation for 4 days, daily
streamflows lagged daily snowmelt by only 3 hours
once significant runoff began (Kane et al. 1981).
Most runoff of snowmelt groundwater in this water-
shed came from permafrost soils (Kane et al. 1981,
Chacho and Bredthauer 1983); snowmelt infiltrated
-------
Functional Profile of Black Spruce Wetlands in Alaska
mineral soils in the nonpermafrost areas (Kane and
Stein 1983). Rapid release of snowmelt is consistent
with a "wetland" streamflow regime (Woo 1988).
Permafrost black spruce slopes also release
stored rainfall via suprapermafrost groundwater.
Surface runoff from an intermittently-exposed
suprapermafrost water table of a valley floor caused
rapid streamflow response to rainfall in a permafrost
basin, but slow flow of suprapermafrost groundwa-
ter from black spruce/moss slopes caused
streamflow to recede slowly (Dingman 1971:67-80;
1973). A permafrost-dominated (53.2%)
subwatershed exhibited higher peak flows (by an
order of magnitude) and lower baseflows than an
upland-dominated subwatershed (Slaughter and
Kane 1979, Haugen et al. 1982). Other Alaska drain-
ages with permafrost soils also have high peak flows
and long recession times (Ford and Bedford 1987).
The streamflow responses of these basins indicate
that permafrost BSWs regulate flows to a lesser ex-
tent than do well-drained uplands.
Release of stored snowmelt and rainfall in
nonpermafrost bogs in some respects resembles that
of frozen BSWs. Flow from nonpermafrost bogs
generally is absent in winter, high during snowmelt
and periods of high precipitation, and low or absent
during extended dry periods (Bay 1969, Boelter and
Verry 1977, Glass 1986a). Approximately 66% of
the annual water yield of unfrozen Minnesota bogs
appears as spring runoff, due, in part, to seasonally
high water tables; and summer streamflow from
Minnesota bogs responds rapidly to rainfall, once
storage is satisfied (Bay 1969), by "slow release of
water from deeper peat horizons as water tables re-
cede" (Bay 1969:99). Depressions within a subarc-
tic "marsh" in a peatland basin supplied surface flow
to streams and created long recessions during sum-
mer dry periods (Woo 1988). Downward groundwa-
ter head gradients in nonpermafrost bogs also may
release some stored precipitation to regional water
tables (e.g., Siegel 1983).
High summer evapotranspiration from mires re-
duces the amount of water released to streamflow or
groundwater recharge (Verry and Boelter 1979); low
spring and fall evapotranspiration has the opposite
effect (e.g., Bay 1969, Woo and Valverde 1981,
Gieck and Kane 1986, Riseborough and Burn 1988,
Gehrels and Mulamoottil 1990). Evapotranspiration
was the primary route for outflow from permafrost-
free Klatt Bog and Connors Bog in Anchorage,
Alaska (Glass 1986a,£), and a Minnesota watershed
containing a bog exported 65% of incident precipi-
tation as water vapor (Verry and Timmons 1982).
Evaporation from Sphagnum recurvum cores ex-
ceeded that from a water surface by a factor of ~2
(Nichols and Brown 1980), demonstrating the pow-
erful ability of mires to transfer stored water to the
atmosphere.
Surface runoff is more likely to occur in
minerotrophic wetlands with characteristically high
water tables than in ombrotrophic wetlands with
highly-permeable acrotelms. Flows from groundwa-
ter fens can occur throughout the year, mainly as a
function of regional hydrogeology, and are more
uniformly distributed than those of bogs, but rapid
runoff of incident precipitation and losses to evapo-
transpiration may actually reduce their ability to
regulate flows (Boelter and Verry 1977).
Black spruce wetlands release water primarily
via groundwater and surface flow during snowmelt
and via evapotranspiration during the summer. High
rates of evapotranspiration, flat topography, and
near-surface storage of incident precipitation charac-
teristic of unfrozen bogs reduce peak flows and cre-
ate long streamflow recession periods (Boelter and
Verry 1977). Ombrotrophic permafrost BSWs ap-
pear to have similar characteristics. Minerotrophic
BSWs can supply baseflows to waterbodies.
Functional Summary
Ombrotrophic BSWs on permafrost slopes dem-
onstrate quantitatively small, short-term flow regu-
lation by retaining some suprapermafrost
groundwater during initial snowmelt and exhibiting
microtopography conducive to detention and depres-
sion storage, should surface flow occur. The desic-
cated organic layers of frozen and unfrozen lowland
bogs probably function similarly, but high water
tables could reduce subsurface storage of snowmelt.
Ombrotrophic BSWs regulate streamflow by quan-
titatively-small subsurface storage of rainfall, limited
by the position of the water table. Evapotranspiration
losses from ombrotrophic wetlands may cause
streamflows to cease in dry weather, which might be
considered an antiregulatory rather than regulatory
function.
Minerotrophic BSWs fed by groundwater per-
form the flow-regulation function by providing long-
36
-------
Hydrologic Functions
term baseflows but have limited ability to regulate
streamflows by subsurface storage. Black spruce
wetlands supplied by suprapermafrost groundwater
provide only quantitatively small, short-term
baseflows. Both permafrost and nonpermafrost
minerotrophic wetlands may provide depression and
detention surface storage, but the magnitude and sig-
nificance of such storage has not been documented.
Despite the ways in which black spruce wetlands act
to regulate flows, in comparison with vegetated,
well-drained uplands of low to moderate slope, the
wetlands generally are less effective in performing
the flow-regulation function.
Slope may indicate various aspects of the flow-
regulation function of ombrotrophic black wetlands.
Organic layers of ombrotrophic permafrost slopes
should drain faster than those of lowland wetlands,
provide more subsurface storage for subsequent pre-
cipitation events, minimize losses to evapotranspira-
tion, and increase the amount of suprapermafrost
groundwater supplied to the valley floor and hence
to downstream flows. In contrast, relatively flat
ombrotrophic wetlands would have lower hydraulic
gradients than slope wetlands, potentially longer
residence times for stored suprapermafrost ground-
water, higher water tables and hence less subsurface
storage capacity for subsequent precipitation events,
and higher evapotranspiration losses. High evapo-
transpiration losses in lowland ombrotrophic wet-
lands might prevent most of the stored water from
augmenting streamflow but should restore subsur-
face storage capacity during dry periods.
Groundwater discharge indicates the ability of a
minerotrophic BSW to provide baseflows but is a
negative indictor for flow regulation by subsurface
storage. In unfrozen wetlands, discharge of ground-
water implies provision of long-term baseflows, al-
though such flows may accumulate largely as aufeis
or naleds ("sheets of ice formed by the freezing of
overflow water"; "stream icing" [Gabriel and Talbot
1984:12,75]) during winter. Discharge of
suprapermafrost groundwater implies quantitatively-
small, short-term additions to seasonal baseflows.
Black spruce wetlands discharging sufficient water
to provide long-term baseflows should have high
water tables and little subsurface storage capacity to
moderate runoff.
Functional Sensitivity to Impacts
Fill diminishes the flow-regulation function of
ombrotrophic BSWs by reducing vertical infiltration
of precipitation (i.e., subsurface storage), increasing
surface runoff, eliminating detention and depression
storage, and reducing evapotranspiration in filled
areas, all of which potentially increase peak flows in
down-gradient waterbodies. Because unvegetated
fills conduct heat, ice-rich, fine-grained soils adja-
cent to fill embankments frequently thaw, subside,
and intercept suprapermafrost groundwater and sur-
face runoff. Linear fills (e.g., roads) and their periph-
eral zones of subsidence can direct intercepted flows
to nearby streams, increasing peak flows. Little miti-
gation for loss of these aspects of flow regulation
appears feasible without extensive hydraulic engi-
neering.
The effects of fill on flow regulation in
minerotrophic wetlands with seasonally-depressed
water tables should parallel that of fill in
ombrotrophic wetlands. For sites discharging
groundwater, fill-induced loss of infiltration capac-
ity may not be significant, but fill covering zones of
groundwater discharge would reduce their ability to
provide baseflows. Placement of highly-permeable
fill or installation of subdrains on nonpermafrost
soils could maintain groundwater discharge for
downstream water supplies, however.
The flow-regulation function of ombrotrophic
BSWs is sensitive to drainage. Drainage that effec-
tively lowers wetland water tables can reduce evapo-
transpiration and increase the proportion of channel
precipitation, which increase both water yield as
surface runoff and peak flow (Verry and Boelter
1979). Mire drainage increases peat decomposition
and can cause surface subsidence (Glaser 1987:67),
the hydrologic effects of which are not clear. Little
mitigation for increased surface runoff appears fea-
sible without extensive hydraulic engineering.
Drainage of groundwater-discharge wetlands is
unlikely to diminish their flow-regulation function
for providing baseflows. Drainage should increase
near-surface storage for precipitation and snowmelt
by depressing water tables, which should increase
short-term flow regulation. Nevertheless, short stor-
age times could to some extent offset increased stor-
age capacities in drained, minerotrophic BSWs.
37
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Functional Profile of Black Spruce Wetlands in Alaska
EROSION CONTROL
Wetlands control erosion by stabilizing soil sur-
faces or dissipating energy of waves and currents
(Carter et al. 1979). Black spruce wetlands affect
rates of erosion by insulating mineral soils and pro-
moting permafrost formation in the zone of wide-
spread discontinuous permafrost. Elsewhere, BSWs
mantle mineral soils with peat and provide mechani-
cal stability for soil surfaces.
Thermal Stability in Permafrost Terrain
Permafrost BSWs thermally stabilize erodible
soils by accumulating an insulating layer of peat,
which in mature wetland stands typically ranges
from 0.3 to 1.0 m in thickness (Foote 1983:47) and
contributes to permafrost formation (Brown and
Pewe 1973). The active layer may extend into min-
eral soil as the season of thaw progresses or may be
confined to organic horizons, depending on peat
thickness. Frozen soils protect against slope move-
ments and erosion by running water, although the
vegetative mat provides most erosion protection, and
the thermal stability function of frozen soil is not
necessarily confined to wetland environments (D. K.
Swanson, Nat. Resour. Conserv. Serv., pers.
commun.).
Permafrost BSWs also protect against
thermokarst phenomena (see Pewe 1982). Factors
disturbing this thermal equilibrium include
windthrow (Wallace 1948), fires and firelines
(Viereck 1982), vehicle traffic (Racine and
Ahlstrand 1991), and clearing of land (Pewe 1982,
Ping 1987). In nearly all cases, depth of thaw in-
creases following disturbance and persists for years
to decades depending upon the severity of distur-
bance. Thaw alone may not lead to erosion (Aldrich
and Slaughter 1983, Racine and Ahlstrand 1991), but
thaw coupled with removal of the organic mat (e.g.,
firelines [Viereck 1973^]) can produce severe ero-
sion on slopes in interior Alaska. Thaw also can
cause the ground surface to subside, pond water, and
initiate growth of thermokarst lakes (Viereck \913b,
Burn and Smith 1988).
Mechanical Stability
The organic mat of BSWs, even when disturbed,
isolates mineral soil from erosive forces. Rainfall
erosion on a trail containing churned-up Sphagnum
sp. and feathermoss in permafrost black spruce was
~3 times that from cutover and undisturbed perma-
frost-free forest plots with intact surface vegetation
but ~6 times less than erosion from stripped mineral
soil on another permafrost-free plot (Aldrich and
Slaughter 1983). Likewise, hydraulic erosion on
permafrost in peat-forming tussock-shrub alpine tun-
dra subjected to multiple vehicle passes was small
(Racine and Ahlstrand 1991). Activities that remove
the organic layer, such as construction of bladed fire-
control lines, expose underlying mineral soils to
thaw and hydraulic erosion (DeLeonardis 1971 in
Slaughter and Aldrich 1989).
Functional Summary
Black spruce wetlands perform the erosion-con-
trol function by insulating permafrost soils so that
the bulk of the soil profile is immobilized in a frozen
state and by mantling erodible mineral soils with a
layer of peat resistant to erosion whether frozen or
thawed. Erosion control by BSWs is not unique.
Permafrost-free, well-drained forest stands also de-
velop mats of organic material in later successional
stages (e.g., Foote 1983), which protect mineral soils
from erosive forces.
Thickness of the organic mat may serve as an in-
dicator of the erosion-control function. Thick or-
ganic layers make it more likely that mineral soils
will remain frozen throughout the season of thaw on
permafrost sites and imply that moderate surface
disturbance will not penetrate sufficiently to expose
mineral soils to thaw and hydraulic erosion.
Functional Sensitivity to Impacts
The erosion-control function of BSWs probably
is only slightly sensitive to fill placement that does
not disrupt surface organics. Thaw subsidence at fill
perimeters on permafrost sites could pond water and
alter vegetation, but erosion would be unlikely on
low to moderate slopes. If the organic mat is not in-
tact, however, severe erosion can result when linear
fills across long permafrost slopes intercept
suprapermafrost groundwater and channel it as sur-
face flow (pers. observation).
Draining may affect the erosion-control function
of BSWs to a greater degree than filling. Ditches that
penetrate peat to mineral soil expose the soil to ero-
sion. On permafrost sites, lateral and vertical thaw
around drainage ditches could cause erosion of
slumping, fine-grained, ice-rich soils.
38
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Hydrologic Functions
DATA GAPS
Hydrologic studies in subarctic and boreal areas
rarely have focused specifically on the hydrologic
functions of BSWs. Data gaps exist with respect to
groundwater discharge and recharge, flow regula-
tion, and sensitivity of hydrologic functions to im-
pacts of fill placement and drainage.
Groundwater Discharge
Wetland literature reveals no comprehensive
studies relating groundwater discharge to the vegeta-
tion and morphology of minerotrophic BSWs in
Alaska, although botanical studies of groundwater-
discharge fens are available for several boreal areas
of Canada (e.g., Slack et al. 1980). Potential sites of
groundwater discharge include large, floating-mat,
groundwater-discharge fens on the Tanana Flats in
interior Alaska (Racine and Walters 1991); perennial
springs discharging subpermafrost groundwater on
alluvial and glaciofluvial fans, as described for the
Yukon Territory (van Everdingen 1988); and lakes
receiving subpermafrost groundwater (Kane and
Slaughter 1973). The distribution and abundance of
such discharge sites and their hydrologic relation-
ships, if any, with included or adjacent BSWs remain
to be investigated.
Mixed stands of black spruce and tamarack occur
in the Interior, apparently on permafrost, but have
not been formally described (Viereck et al. 1992:77).
Studies of wetland vegetation outside Alaska, how-
ever, often identify tamarack with fens (e.g., Zoltai,
Tarnocai et al. 1988). Hydrologic investigations of
Alaska spruce-tamarack stands would clarify their
trophic status and sources of water.
Groundwater Recharge
The relationship between BSWs and recharge of
regional groundwater has received little study in
Alaska. Several unfrozen bogs in Anchorage, Alaska
contributed little to regional groundwater supplies
(Glass 1986a,£>), but more extensive hydrologic
study of unfrozen ombrotrophic wetlands and their
relationships to regional water tables is necessary.
Some minerotrophic wetlands of interior Alaska
have been reported as unfrozen (e.g., Drury 1956:19-
21, Calmes 1976:8) based on probing 1 to 2 m from
the surface rather than drilling to greater depths.
Presence or absence of taliks extending to
subpermafrost groundwater should be verified for
various minerotrophic wetlands. Although ground-
water recharge by fens probably is rare, seasonally-
downward head gradients (Glaser 1987:19-20) could
occur in Alaska. Piezometric studies within unfrozen
BSWs would clarify their relationships to
subpermafrost aquifers.
Flow Regulation
Hydrologic studies of flow regulation by rela-
tively flat BSWs in interior Alaska, unlike those of
permafrost slopes, are lacking. Whether or not the
slopes of permafrost BSWs actually produce mea-
surable differences in associated streamflow re-
sponses is not clear because some variables (e.g.,
higher hydraulic gradients and potentially higher
subsurface storage capacity of ombrotrophic slopes
as compared to floodplain bogs) may offset each
other, and researchers have not conducted compara-
tive studies. Evapotranspiration losses (Glass
1986a,£>) and "nearly level bog topography and the
large detention storage of surface peats" (Boelter and
Verry 1977:17) provide short-term flow regulation in
unfrozen lowland bogs, but this conclusion should
be verified for the range of Alaska BSWs. The role
of minerotrophic BSWs in maintaining biologically
important streamflows in Alaska also should be in-
vestigated.
Erosion Control
The erosion-control function of undisturbed
BSWs is well-established. Peat layers protect erod-
ible soils from the erosive force of flowing water
whereas gross disturbance of such layers can pro-
duce severe erosion.
Functional Sensitivity to Impacts
The hydrologic sensitivity of Alaska BSWs to
impacts of fill placement and drainage remains
largely unexplored. Glass (1986
-------
Functional Profile of Black Spruce Wetlands in Alaska
WATER QUALITY FUNCTIONS
The physiological processes of microorganisms,
plants, and animals coupled with slow water veloci-
ties and physical settling of particulates are the main
factors affecting water quality in wetlands (Sather
and Smith 1984:11). These physical, chemical, and
biological processes buffer changes in the quality of
water discharged from wetlands (Kadlec and Kadlec
1979). Water quality functions of wetlands include
nutrient transformation, retention, and removal
(Larson et al. 1988), which can improve water qual-
ity where wetlands receive high loadings of N and P
from human activities (van der Valk et al. 1979,
Sather and Smith 1984:11-20). Wetlands also can
retain sediment and immobilize or degrade toxic
pollutants. This chapter examines sediment reten-
tion, nutrient uptake, nutrient transformation, and
contaminant removal by BSWs and topics for further
research on their water quality functions.
SEDIMENT RETENTION
Sediment retention or trapping is considered ei-
ther a hydrologic or a water quality function because
of its relation to erosion control and consequent ef-
fect on water quality (Carter et al. 1979, Sather and
Smith 1984:6-7, Larson et al. 1988). Settling and
"filtering" by near-surface flow through organic
material retain sediment in wetlands. Because sedi-
mentation is inversely proportional to water velocity
(Boto and Patrick 1978 in Brown and Stark 1989),
slow wetland flows are conducive to settling of sus-
pended solids (Elder 1988).
Low-velocity or nearly stagnant flows character-
ize basin wetlands (Brown 1990). Closed basins re-
tain nearly all inorganic sediment (Carter et al.
1979), and open basins retain significant quantities,
although resuspension can occur in some systems
(Kadlec and Kadlec 1979). Even wetlands on slopes
retain sediment if water velocities are low (Novitzki
1979).
The microtopographies and permeable moss
mats of BSWs enhance their potential for sediment
retention. Sphagnum mosses form hummocks on
bog surfaces, and the strings and flarks of northern
ribbed fens provide microtopographic relief (e.g.,
Zoltai, Tarnocai et al. 1988). The combination of
peat barriers and depressions retains water and im-
pedes rapid runoff. Suspended solids in water seep-
ing through fen strings are likely to settle out within
the organic matrix.
Flows across the surfaces of ombrotrophic BSWs
(e.g., infiltration of snowmelt and precipitation) pri-
marily are downward and should carry sediment
particles into the moss mat. Flows across the sur-
faces of minerotrophic BSWs primarily are upward
or horizontal, but downward head gradients may
exist at times (Glaser 1987:20). Although sediment
retention may be inhibited in the immediate area of
upward groundwater flows, horizontal and down-
ward flows could carry particulates into the sub-
strate. Once within the organic matrix of a
peat-forming wetland, particulate material should
not be exposed to sufficiently high water velocities
to become remobilized.
Suspended Solids in Wetland Runoff
One measure of a wetland's ability to retain sedi-
ment is the concentration of total suspended solids
(TSS) in runoff from the wetland. Low levels of TSS
imply wetland sediment retention. Measurements of
suspended solids yields from undisturbed and dis-
turbed mires provide evidence for the sediment-re-
tention function of BSWs.
40
-------
Water Quality Functions
Northern peatlands receiving wastewater reduce
TSS concentrations (Kadlec 1987). Although
ombrotrophic BSWs should effectively remove sus-
pended solids from anthropogenic waste streams,
conversion to minerotrophic wetlands likely would
result (D. K. Swanson, Nat. Resour. Conserv. Serv.,
pers. commun.). Undisturbed ombrotrophic wet-
lands rarely should receive natural sediment loadings
in excess of atmospheric deposition.
Minerotrophic, organic-substrate wetlands re-
move suspended solids from influent anthropogenic
waste streams and storm water: TSS concentration
declined 76% downstream of a discharge into a
Typha-Scirpus marsh (Kent 1987), and another cat-
tail marsh retained 94 to 98% of influent sediment
loads (Gehrels and Mulamoottil 1990). Similarly, a
spruce-tamarack fen in Minnesota retained 34%, and
an associated marsh 44%, of influent TSS (Brown
and Stark 1989).
In interior Alaska, TSS concentrations measured
over several years in an undisturbed drainage con-
taining a high proportion of permafrost BSWs aver-
aged 0.23 mg-L'1 and were <8 mg-L-1 even during
high flows, comparable to a paired forested water-
shed containing little permafrost (Hilgert and
Slaughter 1983, 1987). Nevertheless, TSS concen-
trations in permafrost watersheds can briefly rise to
much higher levels during snowmelt runoff (e.g.,
1,337 mg-L-1 declining to <200 mg-L'1) than are typi-
cal for the remainder of the year (Chacho 1990).
Runoff from relatively undisturbed, non-perma-
frost peatlands shows mean TSS concentrations on
the same order as that from BSWs; disturbed,
nonpermafrost mires show slightly greater TSS con-
centrations (Table 15). Levels of suspended solids
measured in runoff from undisturbed, and to some
extent disturbed, mires are comparable to those
found in typical undisturbed, nonglacial streams in
Alaska (cf. U.S. Geol. Surv. 1978:279-351).
Functional Summary
Black spruce wetlands appear to perform the
sediment-retention function. Few quantitative com-
parisons of TSS concentrations in runoff from BSWs
with runoff from other wetlands and uplands are
available, but the physical structure of peatlands ar-
gues for sediment retention. Black spruce wetland
surfaces often show microtopographic variation, are
composed of permeable peat, and have slow water
velocities. Minerotrophic BSWs, often characterized
by surface flows and inputs of runoff from upland
areas, have a greater opportunity to remove sus-
pended solids from the water column than do
ombrotrophic wetlands, which primarily receive in-
puts from precipitation and have little or no surface
flow.
Indicators of the sediment-retention function in-
clude features that slow water movement such as
Table 15. Typical concentrations of total suspended solids (TSS) in runoff from nonpermafrost peatlands.
Mire
Type
Bog
Poor Fen
Fen
Bog
Connors1
"Bog"
Klatt
"Bog"'
Mire
Location
Minnesota
Minnesota
Minnesota
Minnesota
Anchorage,
Alaska
Anchorage,
Alaska
TSS (mg-L'1)
5.1
5.3
5.4
13.7
5.6 to 22.5
5.8 to 53.0
Notes
Average runoff value
Average runoff value
Average runoff value
Average runoff value - peat mining
present
Surface water samples - surface
disturbance present
Surface water samples - surface
disturbance present
Source
Clausen and Brooks
(1983ft)
Clausen and Brooks
(1983ft)
Clausen and Brooks
(1983ft)
Clausen and Brooks
(1983
-------
Functional Profile of Black Spruce Wetlands in Alaska
permeable moss surfaces, Sphagnum hummocks,
pools, strings, and flarks. Sites with significant in-
puts of suspended solids may show visible sediment
deposits as well.
Functional Sensitivity to Impacts
The sediment-retention function of BSWs is sen-
sitive to placement of fill. Snowmelt and precipita-
tion carry suspended solids off fill surfaces, erode fill
slopes, and deposit sediment in remaining wetlands
or drainageways. Increased inputs of suspended sol-
ids combined with reduced wetland areas for sedi-
ment retention increase unit-area sediment loadings,
which may reduce sediment-retention capacities. Fill
reduces cross-sectional areas of flow paths within
minerotrophic wetlands having surface flow, which
may increase water velocity and also reduce sedi-
ment-retention capacity. Likewise, fill in
ombrotrophic wetlands with little or no surface flow
may force shallow groundwater to the surface ren-
dering sediment retention less effective.
Paving or armoring fill surfaces or re-establish-
ing dense vegetative cover with an organic surface
layer, minimizing fill area, and reducing influent
TSS concentrations (e.g., establishing up-gradient
vegetative buffers) could partially mitigate the im-
pacts of fill on sediment retention by remaining
BSWs. Although paving or armoring would prevent
erosion of the fill, it would not prevent runoff of
other anthropogenic solids (e.g., sand) and would
adversely affect several other wetland functions.
The sediment-retention function of BSWs is sen-
sitive to drainage, as shown by higher levels of TSS
in runoff from mined bogs, which usually are
drained, than in runoff from undisturbed bogs (e.g.,
Clausen and Brooks 1983a). In permafrost wetlands,
ditching in thaw-unstable materials such as ice-rich
muck, a mixture of well-decomposed organic mate-
rial and mineral soil (Gabriel and Talbot 1984:73),
could produce severe erosion. Drainage also may
increase surface and subsurface flow velocities, and
hence decrease sediment retention, in response to
increased hydraulic gradients in the vicinity of drain-
age ditches. These effects should be more apparent
for minerotrophic sites with surface flows than for
ombrotrophic sites.
The adverse effects of drainage on sediment re-
tention can be self-limiting as water tables fall be-
cause hydraulic conductivities (and thus
groundwater flow velocities) decrease with depth
(Boelter and Verry 1977, Verry and Boelter 1979),
and drained minerotrophic areas can become
ombrotrophic (e.g., Glaser et al. 1981). Avoiding
ditch excavation in permafrost BSWs and limiting
ditch depths in unfrozen wetlands to avoid mineral
soils would reduce erosion potential. Settling ponds
incorporated in wetland drainage systems might par-
tially mitigate lost sediment-retention capacity.
NUTRIENT UPTAKE
Wetland plants remove sufficient nutrients from
influent water to meet growth requirements, and
some vascular plants concentrate excess nutrients in
tissue by luxury consumption, although leaching and
decomposition subsequently release many of the
stored nutrients (Kadlec and Kadlec 1979). Never-
theless, accumulated detritus retains some nutrients
(Adamus and Stockwell 1983:23). Peatlands in gen-
eral accumulate N and P in organic substrates
(Whigham and Bayley 1979). In BSWs,.nutrient
demands and cycling by trees, shrubs, and herba-
ceous vegetation are supplemented by those of a
thick moss layer.
Moss Layer
Mosses dominate the ground cover of
ombrotrophic BSWs: feathermosses in drier stands
and Sphagnum mosses in wetter sites (Foote
1983:46-48,69-79). In bogs, nutrients reach the moss
layer via atmospheric deposition (Malmer 1988) and
litterfall from tree, shrub, and herbaceous vegetation;
thus, mosses are "filters" that intercept nutrient in-
puts to the forest floor by virtue of their position
above the root zone of vascular plants (Oechel and
Van Cleve 1986). Nutrient demand by mosses can
exceed that supplied by throughfall and litterfall for
several elements (Figure 5). Mosses effectively com-
pete with black spruce on permafrost-dominated
sites, with element uptakes sometimes exceeding
those of aboveground components of black spruce
(Oechel and Van Cleve 1986).
Mosses are nutrient sinks because they rapidly
take up nutrients (e.g., N and P) and retain them until
moss tissues decompose (Weber and Van Cleve
1984, Oechel and Van Cleve 1986, Malmer 1988,
Urban and Eisenreich 1988). Feathermosses retained
>90% of recoverable I5N 28 months following appli-
cation to a black spruce site (Weber and Van Cleve
42
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Water Quality Functions
l Nutrient Addition (throughfall;
and litterfall) \
I Nutrient Uptake (green tissue)
N
K
NUTRIENT
Ca
Figure 5. Nutrient uptake by green moss tissue in a permafrost black spruce stand, interior Alaska, as compared
to nutrient addition by precipitation throughfall and litterfall (Oechel and Van Cleve 1986).
1981), with minimal export by leaching, reducing its
availability to vascular plants rooted in deeper or-
ganic matter (Weber and Van Cleve 1984). Mosses
decompose "about 10% as fast as vascular plant tis-
sue" (Oechel and Van Cleve 1986:122).
Moss production (e.g., -120 g-m"2-yr') can ex-
ceed that of aboveground production of trees (e.g.,
102 g-nr2-yr') in BSWs (Oechel and Van Cleve
1986). The productivity of moss on a variety of
black spruce sites averaged 100 g-nr2-yr' as com-
pared to 33 g-nr2-yr' for tree foliage (Van Cleve,
Dyrness et al. 1983). Slow decomposition of moss in
black spruce stands, combined with significant an-
nual production, produced accumulations of organic
matter averaging 7.6 kg-nr2 for several interior
Alaska sites, with -50 yr turnover times for organic
matter in forest floors (Van Cleve, Oliver et al.
1983).
"Photosynthesis and productivity of forest floor
mosses in the taiga" are severely nutrient limited
(Oechel and Van Cleve 1986:133) as shown by the
responses of mosses to nutrient addition. Two
sources of added nutrients have been studied in peat-
forming wetlands: fertilizers applied for experimen-
tal or silvicultural purposes and sewage effluent ap-
plied for wastewater treatment. Fertilizer increased
both growth and photosynthesis of Sphagnum
nemoreum, increased photosynthesis in new shoots
of Hylocomium splendens but caused salt damage to
overwintered shoots, and decreased growth in H.
splendens and Pleurozium schreberi (Skre and
Oechel 1979). Similarly, Bartsch (1991 in Bartsch
and Schwintzer 1994) noted increased production in
fertilized Sphagnum mosses.
Small quantities of sewage effluent and inorganic
fertilizer caused Sphagnum shoots near fertilizer
pellets to become intensely green, probably indicat-
ing increased production, with retention of added
nutrients in the uppermost portion of Sphagnum
cores (Sanville 1988). Concentrations of total P (TP)
were high in the upper 2 cm of cores from plots
treated with P, alone or in combination with N and/
or sewage (Sanville 1988). The positive responses of
Sphagnum mosses to nutrient addition imply signifi-
cant potential for nutrient uptake in ombrotrophic
BSWs. Although wetlands containing Sphagnum can
43
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Functional Profile of Black Spruce Wetlands in Alaska
remove nutrients from wastewater (Verry and
Timmons 1982), species composition is likely to
change, as occurred in a fen receiving sewage efflu-
ent in Minnesota (Brown and Stark 1989).
Tree, Shrub, and Herb Layers
Low soil temperature and high soil moisture re-
duce element cycling (and thus nutrient availability
to vascular plants) in permafrost black spruce stands
(Van Cleve et al. 1991). These stands have the low-
est tree productivities and nutrient fluxes among
Alaska's treed taiga sites (Van Cleve, Dymess et al.
1983; Viereck et al. 1983). Conditions of low nutri-
ent availability in BSWs suggest that their trees,
shrubs, and herbs should efficiently acquire and re-
tain nutrients. Conversely, adaptation of these plants
to a low-nutrient environment suggests potentially
limited capacities for uptake of nutrients, as shown
by Van Cleve, Oliver et al. (1983) for black spruce
(Figure 6).
Vascular plants primarily acquire nutrients
through their roots, presumably enhanced by mycor-
rhizal associations with fungi, which are common in
taiga species (Flanagan 1986) such as black spruce
(Tyrrell and Boerner 1987, Summerbell 1989) and
mountain-cranberry (Vaccinium vitis-idaea)
(Dickinson 1983). Black spruce roots elongated at
greater rates than other taiga tree species on cold,
wet sites, probably favored by high soil moisture
(Tryon and Chapin 1983). Fine roots, responsible for
absorbing nutrients, made up 72% of root biomass
on a permafrost black spruce site (Tryon and Chapin
1983). Black spruce produces biomass more effi-
ciently (i.e., ratio of annual biomass production to
element requirement) than do taiga hardwoods and
partially offsets low nutrient uptake by retaining
nutrients, adding an annual increment of 113 g-nr2 of
aboveground biomass while losing only 43 g-m"2 to
litterfall in one study (Van Cleve, Oliver et al. 1983).
Shrubs within ombrotrophic and weakly
minerotrophic BSWs also are adapted to low nutri-
ent availability: shallow rooting depths allow early
uptake of nutrients by shrubs in the spring (Chapin
1983a, Tryon and Chapin 1983), evergreen erica-
ceous plants (e.g., Labrador-tea) conserve scarce
nutrients within plant tissues (Larsen 1982:148),
;• Black Spruce
• Other Taiga Trees
N
K
NUTRIENT
Ca
Figure 6. Comparative nutrient requirements for black spruce and other taiga trees as a group (white spruce, quak-
ing aspen, paper birch, and balsam poplar) (Van Cleve, Oliver et al. 1983).
44
-------
Water Quality Functions
evergreen shrubs exhibit earlier fine root growth in
the spring than do deciduous shrubs (Kummerow et
al. 1983), and shrubs adapted to low-nutrient envi-
ronments have slow growth rates (Bryant et al.
1983). Evergreen and deciduous plants adapted to
bog environments both produce photosynthate more
efficiently with respect to N than do nonbog plants
(Larsen 1982:149).
Shrubs play a larger role in nutrient uptake and
cycling in BSWs than suggested by their small bio-
mass (Chapin 19830). Chapin (1983a) reported that
Labrador-tea and bog blueberry accounted for only
0.8% of aboveground vascular plant biomass but
2.8% and 2.4% of the standing crop of N and P at a
permafrost forest site. Shrubs as a group accounted
for 24% and 19% of annual uptake of N and P by
'aboveground portions of vascular plants (including
trees) and 16% of their annual biomass increment.
Annual biomass turnover for shrubs at this site was
34 to 43%. Rapid biomass turnover in wetland
shrubs suggests that uptake would remove anthropo-
genic nutrients from the soil solution, deposit them
in plant structures, and return them to the forest floor
as litterfall over the course of several years. A por-
tion of the litterfall nutrients from shrubs potentially
would be bound in forest floor organic matter with
turnover times of 100 to 1000 yr, as Flanagan and
Van Cleve (1983) postulated for the mineral nutrient
cycle of deciduous trees.
Responses of vascular plants to experimental and
silvicultural fertilization and application of sewage
effluent demonstrate potential nutrient uptake in
BSWs. Fertilized (N, P, and K) leatherleaf produced
a significant growth response in a bog (Bartsch
1994) but not in a poor fen, indicating nutrient defi-
ciency in the bog environment (Bartsch and
Schwintzer 1994). With respect to ericaceous plants,
Reader (1980) cites research showing that 50 kg
N-ha'1 should compensate for naturally occurring de-
ficiencies in bog soils. At least some of the plants
and soil characteristics of tundra are shared by taiga
wetlands (Kummerow et al. 1983), implying that
taiga plants should show similar responses to N-fer-
tilized tundra cores, which approximately doubled
leaf area and total aboveground biomass (Billings et
al. 1984).
Fertilizer trials with seeded annual ryegrass
(Lolium temulentuni) in a disturbed, wet graminoid-
low shrub meadow (at least partially minerotrophic)
with mucky peat soils revealed N, P, and K deficien-
cies (Helm et al. 1987). Aboveground biomass of
vascular plants in Alaska mire plots fertilized with
N+P and sewage effluent+N+P increased compared
to controls, and some graminoids showed a signifi-
cant response to P alone, suggesting both N and P
deficiencies in the mire (Sanville 1988). Actual
wastewater discharges impose high nutrient loads on
wetlands (Kadlec 1979), often increasing vascular
plant biomass (Figure 7). Ombrotrophic wetlands re-
ceiving large quantities of effluent likely would soon
become sparsely-treed fens or treeless marshes.
Nitrogen deficiency limits tree growth in boreal
forests (Weetman 1982), and forest floors on cold,
wet sites (e.g., BSWs) have particularly low concen-
trations of available N (Flanagan and Van Cleve
1983). Taiga conifers respond to N fertilization with
increased growth, although the response is less in
black spruce than in other tested species (Weetman
1982). Diameter increments of black spruce treated
with 112 or 224 kg N-ha~' on a gleyed-soil site re-
ceiving groundwater seepage increased significantly
over controls (Foster et al. 1986). Black spruce seed-
lings grown under controlled conditions show no
significant growth response to phosphate fertiliza-
tion, however (Chapin et al. 1983).
Minerotrophic BSWs may not be nutrient defi-
cient with respect to plant growth requirements, but
their characteristic plants (e.g., sedges) can respond
to additional nutrients by virtue of adaptations to
high-nutrient environments. Upland taiga tree spe-
cies have much higher maximum growth rates than
mire conifers, yet show marked responses to nutrient
addition (Chapin 1986). Tamarack, characteristic of
fens, has a greater maximum growth rate than black
spruce, characteristic of bogs (Chapin 1986).
A speculative route of nutrient uptake by BSWs
is assimilation of atmospheric ammonia. Langford
and Fehsenfeld (1992) presented evidence that the
canopy of a montane-subalpine forest of lodgepole
pine, ponderosa pine (Pinus ponderosa), spruce, fir,
and aspen in Colorado acted as a sink for anthropo-
genic ammonia. Conversely, the forest acted as a
source of ammonia at low ambient ammonia con-
centrations. Taiga forests, and by extension black
spruce mires, may or may not respond to atmo-
spheric ammonia in the same way as the montane-
subalpine forest.
45
-------
w
Functional Profile of Black Spruce Wetlands in Alaska
0 Wastewater Area
• Control Area
m
Cattail
Sedge
SPECIES
Figure 7. Cattail and sedge biomasses at wastewater discharge and control sites, Hay River, N.W.T.
(Kadlec 1987).
Functional Summary
Black spruce wetlands perform the nutrient-up-
take function. Ombrotrophic and weakly
minerotrophic wetlands are nutrient-poor environ-
ments, and many of their characteristic plants, in-
cluding black spruce, can assimilate anthropogenic
nutrients as shown by increased net primary produc-
tion following nutrient addition. Sphagnum mosses
- positioned to intercept nutrients in precipitation,
throughfall, and litterfall - effectively compete with
vascular plants for nutrients. Shrubs rapidly turn
over biomass, removing nutrients from the soil solu-
tion and shunting them to accumulating organic ma-
terial. Plants characteristic of minerotrophic BSWs
also respond to nutrient addition.
Nutrient uptake is not confined to BSWs; upland
taiga communities share the ability to remove nutri-
ents from anthropogenic sources (e.g., wastewater
discharge, nonpoint-source pollution). Ombro-
trophic sites receive only atmospheric inputs of nu-
trients and thus have a limited opportunity for
nutrient removal, although nutrient-poor runoff from
bogs could serve to dilute anthropogenic nutrients in
receiving waters. Minerotrophic BSWs that receive
surface water, in contrast, have ample opportunity
for uptake of waterborne anthropogenic nutrients.
Because all plant communities take up nutrients
from their environments, no specific indicators of
the nutrient-uptake function need be applied to veg-
etated wetlands.
Functional Sensitivity to Impacts
The nutrient-uptake function of BSWs is sensi-
tive to fill, which, unless vegetated, has little capac-
ity for nutrient uptake. Runoff from fill surfaces
would carry nutrients deposited on, or contained
within, those surfaces into adjacent wetlands and
increase their nutrient loadings. Revegetating fill
surfaces to achieve dense vegetative cover could
ameliorate excessive nutrient loading from fill run-
off in the absence of high anthropogenic nutrient
inputs (e.g., fertilization), but such surfaces could
riot remove waterborne nutrients within the wetland.
Draining BSWs reduces, but does not eliminate,
uptake of waterborne nutrients by wetland plants.
Ditching channelizes flow so that waterborne nutri-
ents have less contact with plant root zones and have
shorter residence times within wetlands. Rates of
46
-------
Water Quality Functions
decomposition, and hence nutrient release from or-
ganic matter, are likely to increase as wetland soils
are drained and become increasingly aerobic. Nutri-
ent release from drained soils could diminish the
capacity of wetland plants for uptake of anthropo-
genic nutrients by increasing total nutrient availabil-
ity. To the extent that natural wetland surfaces and
vegetation are maintained following drainage, the
functional capability to take up nutrients remains
present, although opportunities for nutrient uptake
are reduced in the absence of surface and near-sur-
face flows.
NUTRIENT TRANSFORMATION
Chemical reactions and biotic metabolic activity
transform nutrients entering wetlands (Mitsch and
Gosselink 1993:120-142). Nutrients can reside for
various times in different chemical forms (e.g., or-
ganic and inorganic), tending to smooth influent
nutrient pulses, and can leave wetlands in other
forms. Some forms of nutrient elements may enter
sinks and effectively be removed from short-term
cycles. Chemical transformations of nutrients occur
as oxidation-reduction or redoxpotentials (potentio-
metric measures of the oxidizing or reducing inten-
sity of a solution [Wetzel 1983:298]) vary with
concentrations of oxygen (Mitsch and Gosselink
1993:123-126) and, to a lesser extent, humic acids
(Wetzel 1983:301). Microbial oxidative-respiratory
reactions transform organic and inorganic com-
pounds under aerobic and anaerobic conditions
(Mitsch and Gosselink 1993:166).
Nitrogen
Nitrogen is a major anthropogenic nutrient trans-
formed by wetlands. The primary N transformations
are fixation, conversion of gaseous N (N2) to organic
N (or to ammonium [Wetzel 1983:235, Alexander
and Billington 1986]); mineralization, conversion of
organic N to ammonium N (NH4-N); nitrification,
conversion of NH4-N to nitrite N (NO2-N) and then
to nitrate N (NCyN); and denitrification, conversion
of NO3-N to N2 (Mitsch and Gosselink 1993:128-
130). The extent to which each of these processes
occurs determines the primary forms taken by N in
BSWs and whether such wetlands act as sources or
sinks for various forms of N.
Fixation: Microbes, which may be aerobic or
anaerobic, heterotrophic or autotrophic, symbiotic or
free living, and may belong to several taxonomic
groups including the cyanobacteria (blue-green al-
gae) and actinomycetes, use the enzyme nitrogenase
to fix N (Waughman and Bellamy 1980, Dickinson
1983). Symbiotic bacteria associated with lichens,
mosses, and vascular plants, as well as asymbiotic
bacteria, fix N in mires and BSWs (Granhall and
Selander 1973, Granhall and Hofsten 1976,
Waughman and Bellamy 1980, Billington 1981,
Dickinson 1983, Florence and Cook 1984).
Rates of N fixation by heterotrophic bacteria in-
crease from ombrotrophic to minerotrophic site con-
ditions but decline somewhat for extremely rich fens
(Waughman and Bellamy 1980). Waughman and
Bellamy (1980) found low levels of heterotrophic
nitrogenase activity in several bogs with pH < 4, and
heterotrophic bacteria accounted for most N fixation
in a black spruce bog in Minnesota (Urban and
Eisenreich 1988). Asymbiotic N-fixing bacteria, in-
cluding Azospirillum spp. and Azotobacter spp., as-
sociated with black spruce and tamarack,
respectively, in wet lowland stands in Alberta (Flo-
rence and Cook 1984). Actinomycetes symbiotic
with alder and sweetgale roots fix N in fens (Moore
and Bellamy 1974:79, Dickinson 1983).
Autotrophic microbes also fix N. Granhall and
Selander (1973) found that moss-associated
cyanobacteria (blue-green algae) fixed most N in
wetter areas of a permafrost bog, but heterotrophic
N-fixing bacteria were active in peat hummocks.
Mosses with epiphytic cyanobacteria showed higher
fixation than those containing intracellular
cyanobacteria or those associated with free-living
cyanobacteria. Despite lower rates of N fixation,
intracellular cyanobacteria persist at lower pH con-
centrations than extracellular forms. Cyanobacteria
occur in hyaline cells of Sphagnum riparium and 5.
lindbergii at extracellular pH concentrations as low
as 4.2, but the symbionts are absent at pH 3.8, char-
acteristic of some other Sphagnum communities
(Granhall and Hofsten 1976).
Cyanobacteria associated with lichens (e.g.,
Nephroma spp. and Peltigera spp.) and mosses fix
most N in high-latitude wetlands (Alexander and
Billington 1986). Lichens containing symbiotic
cyanobacteria show high levels of N fixation
(Granhall and Selander 1973), exceeding those of
lichens without phycobionts by 1 to 2 orders of mag-
nitude in an Alaska study (Alexander and Billington
47
-------
Functional Profile of Black Spruce Wetlands in Alaska
1986). Lichens containing symbiotic cyanobacteria
fix N at higher rates than complexes of mosses and
cyanobacteria, but mosses can account for the major-
ity of N fixation by virtue of their abundance at
Alaska black spruce sites (Billington 1981:55). Be-
tween-site and interannual variation in N fixation ap-
parently is small in black spruce ecosystems, with
nitrogen fixation (based on acetylene reduction)
ranging from 0.9 to 1.4 kg N-ha~'-yr' for two perma-
frost and nonpermafrost black spruce sites
(Billington and Alexander 1983). These values are
similar to those found for wetlands in other subarc-
tic and arctic locations (Alexander and Billington
1986).
Mineralization: Nitrogen resides in forest floors
of taiga black spruce for an average of 61 yr as com-
pared to 18 yr for temperate coniferous forests (Van
Cleve, Oliver et al. 1983). Mineralization (ammoni-
fication [Mitsch and Gosselink 1993:129]) removes
N from long-term storage during decomposition of
organic matter by transforming organic N to NH4-N,
a rapidly cycling but volatile form easily taken up by
living organisms. Bogs apparently cycle N exclu-
sively as NH4-N (Urban and Eisenreich 1988), the
dominant form of inorganic N in black spruce stands
of interior Alaska (Weber and Van Cleve 1984).
Substrate quality, including C/N ratios, energy
limitations imposed by lack of easily-degradable C
compounds, and nutrient content of litter, as well as
temperature and moisture, affect organic matter de-
composition (Moore 1981; Flanagan and Van Cleve
1983; Fox and Van Cleve 1983; Van Cleve, Oliver et
al. 1983; Flanagan 1986; Van Cleve and Yarie 1986).
Birch, poplar, and aspen stands have higher tempera-
ture sums above 0°C, lower soil moistures, lower C/
N ratios, and higher rates of N mineralization than
do black spruce stands (Van Cleve and Yarie 1986).
Low rates of mineralization coupled with accumulat-
ing organic matter would be consistent with a wet-
land acting as a sink for N.
Nitrogen concentrations in Alaska peat soils are
highest some distance below the surface; therefore,
low temperatures in the zone of maximal N concen-
tration minimize rates of mineralization (Heilman
1966). Mineralization and immobilization of N in
forest floors of black spruce stands occur mainly in
moss layers subject to environmental variation rather
than in colder underlying organic matter, and these
events are more frequent on warmer, nonpermafrost
sites with lower C/N ratios (i.e., more favorable for
decomposition) than on permafrost sites (Weber
1982). Heating an experimental black spruce site in
interior Alaska increased decomposition and re-
leased N, P, and K (Van Cleve, Oliver et al. 1983).
Precipitation promotes mineralization by wetting
moss layers (Weber and Van Cleve 1984), but drain-
age increases peat decomposition (Glaser 1987:67)
and thus mineralization of N. The effects of fertili-
zation on mineralization are not clear. Mire drainage
and fertilization with P and K for silvicultural pur-
poses increased mineralization (Remrod 1980) but
mineral fertilizers reduced mineralization on drained
peatlands converted to agriculture (Baranovskiy
1991) and suppressed microbial respiration in forest
litter (Flanagan 1986).
Mineralization rates in North American wetlands
may vary with latitude. Mineralization and plant
uptake dominate rapid cycling of N in temperate
bogs (Urban and Eisenreich 1988), but taiga black
spruce ecosystems, including permafrost BSWs,
mineralize only small amounts of N (Van Cleve,
Oliver et al. 1983; Van Cleve and Yarie 1986).
Alaska BSWs mineralize less N than taiga hardwood
stands and much less than a temperate Minnesota
bog but about the same amount as the acrotelm of an
European blanket peat (Table 16).
Nitrification: Bacteria or fungi transform re-
duced forms of N to more oxidized forms in the pro-
cess of nitrification (Wetzel 1983:234-235, Flanagan
1986, Mitsch and Gosselink 1986:97). Nitrate is the
end product of these transformations but, as an an-
ion, is not retained by the cation exchange capacity
of wetland peat (Moore and Bellamy 1974:122-123,
Weber and Van Cleve 1981, Mitsch and Gosselink
1986:97). High rates of nitrification tend to make a
wetland a source, rather than a sink, for NO3-N.
Nitrifying bacteria occur in poor fens (Dickinson
1983), but nitrification is absent under anaerobic
conditions (Wetzel 1983:236) and much reduced or
absent in ombrotrophic peatlands (Moore and
Bellamy 1974:98-99, Dickinson 1983, Mitsch and
Gosselink 1986:98, Urban and Eisenreich 1988).
Tannins and other dissolved organic compounds in-
hibit nitrifying bacteria (Rice and Pancholy 1972,
1973 in Wetzel 1983:236), which may account for
their low numbers in bogs. Flux between NH4-N and
NO3-N in a blanket bog (0.03 kg N-ha-'-yr1) was in-
consequential as compared to NO3-N input via rain-
48
-------
Water Quality Functions
Table 16. Comparative N mineralization in several European and North American mires and forest stands.
Site Type and Location
Bog - Minnesota
Black spruce - Quebec
Black spruce - Alaska
Blanket peat - Europe
Birch, poplar, aspen - Alaska
N Mineralization (kg N-ha'^yr"1)
43 to 59
11
7.9 to 18
9
24 to 58
Source
Urban and Eisenreich (1988)
Weetman and Webber (1972 in
Bonan 1990a)
Van Cleve et al. (1981), Flanagan
and Van Cleve (1983)
Dickinson (1983)
Flanagan and Van Cleve (1983)
fall (1 kgN-ha-'-yr1) (Dickinson 1983).
Nitrification rates in North American mires are
not well documented, but studies of taiga forest eco-
systems are pertinent. Incubated organic matter from
a mature black spruce-lichen woodland yielded
nearly equal concentrations of NH4-N and NO3-N
(Figure 8), but Moore (1981) characterized nitrifica-
tion as low in the subarctic soils tested. In contrast,
concentrations of NO2-N and NO3-N in an Alaska
permafrost BSW generally were <0.1 mg N-kg'1 soil
(Sparrow and Sparrow 1988).
Pools of NH4-N consistently are larger than pools
of NO3-N in Alaska black spruce stands (Table 17).
Ratios of NH4-N pools to NO3-N pools, calculated
for individual samples from Weber and Van Cleve
(1984), range from approximately 3.8 to 22.8 for
permafrost sites and from 1.4 to 18.3 for
nonpermafrost sites, consistent with the ratio (>10)
reported for permafrost black spruce by Van Cleve
and Dyrness (1983&). Small pools of NO3-N do not
necessarily indicate comparably low rates of nitrifi-
cation if plants rapidly assimilate NO3-N, but I5NO -
N transformations appear slow in black spruce
forests (Weber 1982:66-67,89). Glucose increased
NO3-N concentrations in black spruce stands, per-
haps by fungal nitrification (Flanagan 1986). This
finding may indicate a greater capacity for nitrifica-
tion than normally is expressed under ambient con-
ditions in BSWs.
Alaska's BSWs frequently develop in later stages
of post-fire secondary succession as permafrost
aggradation or paludification saturates near-surface
soils. Low nitrification rates might be expected in
these wetlands because nitrification declines during
later stages of secondary succession in some seres
(Vitousek et al. 1989). Based on their acidic, anaero-
bic conditions, as well as typical successional status,
ombrotrophic BSWs probably show little nitrifica-
tion. Although comparative data are lacking, surface
layers (aerobic) of minerotrophic BSWs might be
expected to show greater nitrification than those of
ombrotrophic wetlands.
Denitrification: Denitrification by bacterial re-
duction of NO2-N and NO3-N to N2 can occur under
aerobic conditions but occurs most intensely under
anaerobic conditions, although acidic water and low
temperatures depress rates of denitrification (Wetzel
1983: 237-238). Bacterial denitrifiers occur in mires,
including those dominated by Sphagnum, and are
more common than nitrifying bacteria (Dickinson
1983) but are sparse at pH < 5.5 (Larsen 1982:156).
A European blanket bog denitrified 1 kgN-ha-'-yr1,
a rate that balanced input of NO3-N by rainfall
(Dickinson 1983). Most literature suggests that sig-
nificant denitrification does not occur in
ombrotrophic mires because nitrification is largely
absent (Urban and Eisenreich 1988).
Soil profiles of BSWs are largely anaerobic,
which would favor denitrification, but are often
acidic, which would depress denitrification. Counts
of denitrifying bacteria in the organic horizons of
control plots in a BSW were <100 cells-g'1 soil
whereas counts from experimentally-oiled plots ap-
proached 10 million cells-g'1 soil, suggesting that oil-
killed vegetation released substrates that enhanced
microbial activity (Sparrow et al. 1978). This obser-
vation indicates a latent capacity of BSWs, particu-
larly minerotrophic wetlands, to transform
anthropogenic inputs, possibly including NCyN.
Significant denitrification would make a wetland a
sink for N as gaseous output of N2 removed N from
internal cycling (Larsen 1982:156) and potentially
49
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Functional Profile of Black Spruce Wetlands in Alaska
16
-g- 14
j| 12
g 10
i s
£ 6
UJ
i 4
8 2
INH4-N
INO3-N
Litter Humus
ORGANIC LAYER
Figure 8. Concentrations ofNH^-N and NOt-N in incubated organic material from a mature black spruce-lichen
woodland, Quebec (Moore 1981).
Table 17. Pools ofNH4-N and NO}-N in wetland and nonwetland Alaska forest stands.
Site Type
Permafrost black
spruce
Permafrost black
spruce
Permafrost black
spruce
Nonpermafrost
black spruce
White spruce
floodplain
NH4-N (kg
N-ha')
0.3 to 0.4
3.24
3.02 to 20.63
0.60 to 32. 1 3
1.8
NO.,-N (kg
N-ha'1)
NA1
0.152
0.34 to 2.04
0.34 to 2.60
trace
Comment
Organic horizon - range
over summer
Forest floor estimates
Fermentation and humus
layers - range tor various
sampling dates
Fermentation and humus
layers - range for various
sampling dates
Forest floor
Source
Sparrow and
Sparrow (1988)
Van Cleve and
Dyrness(1983b)
Weber and Van
Cleve (1984)
Weber and Van
Cleve (1984)
Walker (1989)
1. NA = not available.
2. Units given as mass-volume"' in cited report, but text
pool sizes for NH4-N and NO3-N) implies mass-area"
context (i.e., direct comparison
' intended for both estimates.
of forest floor
-------
Water Quality Functions
decreased waterborne output of NO3-N.
Phosphorus
Chemists treat P as dissolved or suspended (par-
ticulate) and subdivide each form into reactive, acid-
hydrolyzable, and organic fractions for analytical
purposes (Am. Public Health Assoc. et al. 1992:4-
108 to 4-109). Inorganic P occurs as orthophos-
phates, which include PO43, HPO;2, and H2PO;',
depending on pH (Mitsch and Gosselink 1993:140);
and acid-hydrolyzable or condensed phosphates, in-
cluding polyphosphates such as detergents and sus-
pended mineral particles such as Fe+3 and Ca+2
phosphates (Wetzel 1983:255-256, Am. Public
Health Assoc. et al. 1992:4-108). Most waterborne P
in freshwater systems is in suspended organic form,
mainly derived from biological processes, but
smaller dissolved pools of a low molecular weight
organic P compound and colloidal P are present and
exchange with other pools of P (Wetzel 1983:
255,257,270). Actual forms of P in wetland ecosys-
tems may not correspond to analytical fractions used
in limnologic or water quality studies, however
(Wetzel 1983:256).
Phosphorus commonly limits biological produc-
tion and, in excess, can cause waterbodies to become
eutrophic (Wetzel 1983:255,284-291; Lowe et al.
1992) because cyanobacteria can fix the additional N
necessary to support biomass production (J.
LaPerriere, Univ. Alaska, pers. commun.). Biologi-
cal assimilation occurs primarily as dissolved inor-
ganic P (Mitsch and Gosselink 1993:140), which is
incorporated in organic compounds: nucleic acids,
commonly the largest fraction in vascular plants;
phospholipids, also common in plant tissue; pro-
teins; esters; and nucleotide phosphates (Chapin and
Kedrowski 1983, Wetzel 1983:255-258, Mitsch and
Gosselink 1993:139). Once biologically transformed
to organic form, P becomes less available and may
be stored for significant periods in living and dead
plant tissues, ameliorating the effects of anthropo-
genic P on waterbodies.
Wetlands often transform, and may be sinks for,
various inorganic and organic fractions of P (van der
Valk et al. 1979). Mitsch and Gosselink (1993:141)
and Wetzel (1983:255-258) describe three general
mechanisms whereby PO4-P is removed from solu-
tion: precipitation, adsorption, and uptake by living
organisms. Leaching and mineralization return or-
ganic P to solution.
Precipitation: Phosphorus precipitates when
PO forms insoluble complexes with metallic ions
such as Fe+3, aluminum [Al+3], and Ca+2 under oxi-
dizing conditions (Stumm and Morgan 1970 in van
der Valk et al. 1979, Wetzel 1983:255-258, Mitsch
and Gosselink 1993:141). Anaerobic conditions at
the sediment-water interface in lakes are known to
release Fe+2 and POy3 to the water column whereas
oxygenation of this zone precipitates FePO4 (Wetzel
1983:261-263). Tundra ponds in northern Alaska
show little precipitation of P minerals, however
(Prentki et al. 1980). Anaerobic (reducing) condi-
tions in BSWs potentially would act against precipi-
tated P remaining insoluble in saturated horizons. In
addition, salts such as A1PO4 become more soluble
at pH < 6 (Wetzel 1983:258), a condition present in
ombrotrophic and weakly minerotrophic peat-form-
ing wetlands.
Adsorption: Mechanisms of PO4-P adsorption in
BSWs are not well-documented. Phosphate adsorbs
(binds) to mineral surfaces and organic material, a
process sometimes supplemented by chelation and
formation of chemical complexes (Wetzel 1983:255-
258, Mitsch and Gosselink 1993:141-142). Phos-
phate adsorbs to peat, even in mires receiving large
anthropogenic nutrient inputs (Whigham and Bayley
1979, Kadlec 1987, Brown and Stark 1989, Mitsch
and Gosselink 1993:141). A calcareous fen peat
sorbed an order of magnitude more P than an acid
Sphagnum peat (Isirimah and Keeney 19836 in
Sikora and Keeney 1983).
Complexes of ferric hydroxides adsorb P in lakes
(Wetzel 1983:255,261), although humic and fulvic
acids may hold Fe and PO4 in solution in peatland
lakes (Engstrom 1984). Sediment P contents of Fe-
rich peats in tundra ponds strongly correlated with
their Fe contents as a result of PO4 sorption (Prentki
et al. 1980), and Fe concentrations that reached 30
mg Fe-g'1 in mineral soil horizons of a Quebec
spruce-lichen woodland apparently bound P (Moore
1980). Representative Fe concentrations in the up-
permost 1 m of Canadian mire peats ranged from 0.5
to 29.7 mg Fe-g-' (Zoltai, Tarnocai et al. 1988; Zoltai,
Taylor et al. 1988), about 1 order of magnitude less
than those of Alaska tundra ponds (Prentki et al.
1980) but perhaps sufficient to cause P adsorption.
Measured P concentrations in several Canadian
mires (Table 18) generally exceeded predicted P
51
-------
Functional Profile of Black Spruce Wetlands in Alaska
concentrations (e.g., <228 |ig P-g-'), based on Fe
concentrations (e.g., <3.7 mg Fe-g'1), using the re-
gression equation of Prentki et al. (1980) for tundra
ponds. This result is consistent with, but does not
necessarily demonstrate, P adsorption to Fe and peat
in taiga mires.
Sorption processes for P may become saturated
near points of heavy loading, such as occurs from
wastewater discharge (Kadlec 1987, Kent 1987) but
may occur sooner for PO4-P than for TP (Jones and
Amador 1992). Orthophosphates, approximated by
soluble or dissolved reactive P (DRP), are rapidly
converted to total suspended P (TSP) in many fresh-
water systems (Prentki et al. 1980, Wetzel 1983:256,
Mitsch and Gosselink 1993:140). Following PO4-P
saturation of subtropical marsh peat, microorgan-
isms that apparently constituted the suspended-P
fraction appeared to undergo hydrophobic and ionic
interactions with.the peat (i.e., adsorption) and thus
provided a continuing route of TP removal (Jones
and Amador 1992).
Uptake By Organisms: Biotic uptake trans-
forms PO4-P to organic P in microscopic and macro-
scopic organisms. A hypertrophic lake receiving
90% of TP in dissolved form yielded -70% TSP in
the water column (Lowe et al. 1992). Likewise,
losses of P in runoff from tundra (wetland) soils oc-
cur primarily as organic fractions (Gersper et al.
1980). Processes such as settling or adsorption to
peat can remove TSP from the water column (Stark
and Brown 1988, Jones and Amador 1992) or from
the soil solution, and organic suspended material can
enter food chains.
Phosphorus deficiency is common in northern re-
gions (Tamm 1968 in Miller et al. 1979). Availabil-
ity of P in a peat-forming wetland of interior Alaska
was only one-third that of an adjacent permafrost-
Table 18. Phosphorus concentrations in several Cana-
dian taiga mires with Fe concentrations <3.7 mg Fe-g'1
(Zoltai, Taylor et al. 1988).
Wetland Type
Northern Plateau Bog
Boreal Fen
Flat Bog
Basin Bog
P Concentration
(ugP-g1)
183 to 620
384 to 1736
278 to 451
263 to 825
free birch forest (Chapin and Kedrowski 1983); a
shrubby sedge meadow was deficient in P with re-
spect to growth of seeded annual ryegrass (Helm et
al. 1987); and content of PO4-P was greater in or-
ganic layers of permafrost black spruce stand in
Alaska than in underlying mineral soil, but the ma-
jority of P was not in available form (Grigal 1979).
Pool sizes for total P apparently can exceed those for
available P by several orders of magnitude in black
spruce stands (Table 19).
Peatlands appear to accumulate less P in
aboveground vegetation than do wetlands with min-
eral substrates (Whigham and Bayley 1979), but
lack of available P creates biotic demand. Green
moss tissue annually took up 4.8 mEq P-nr2 on a per-
mafrost black spruce site even though throughfall
and litterfall only supplied 0.6 mEq P-nr2 (Oechel
and Van Cleve 1986). Fertilization increased photo-
synthesis in the mosses Sphagnum nemoreum and
Hylocomium splendens, and P increased annual
growth in S. nemoreum (Skre and Oechel 1979). In
Sphagnum mosses, P concentrates in the youngest
tissue (Malmer 1988, Sanville 1988) and is retained
until the mosses become litter (Malmer 1988).
Mycorrhizal fungi efficiently acquire P for asso-
ciated vascular plants (Miller et al. 1979) but uptake
in BSWs is affected by several factors: growth strat-
egies of individual species, soil temperature, soil
moisture, dissolved ions, and evergreen versus de-
ciduous leaf habit (Tilton 1978, Chapin and Try on
1983, Grime and Anderson 1986, Horn 1986). Al-
though taiga trees and shrubs absorb PO4-P at lower
rates in cold wetlands than in warm uplands, ever-
green species and the deciduous bog blueberry
take up PO4-P at low concentrations on cold sites
more effectively than do deciduous species in gen-
eral (Chapin and Tryon 1983). Understory shrubs
representing only 0.8% of aboveground vascular
plant standing crop accounted for 19% of P assimi-
lated by aboveground portions of vascular plants on
a permafrost black spruce site (Chapin 1983a). Vas-
cular plants in bogs fertilized with P had higher TP
contents than controls (Sanville 1988).
Tree species adapted to low-nutrient environ-
ments show less growth response to high PO4-P con-
centrations than those adapted to high-nutrient
environments (Chapin et al. 1983). Black spruce has
the lowest capacity for absorption of PO4-P among
taiga trees (Chapin 1983&), with a minimum P re-
52
-------
quirement of only 0.7 kg P-ha"1 in interior Alaska
(Van Cleve, Oliver et al. 1983), and has lower foliar
P content on cold sites than on warm sites (Heilman
1968, Horn 1986). By retaining needles for >20 yr
(Horn and Oechel 1983) black spruce mitigates its
low capacity for uptake of PO4-P and maximizes
storage time for organic P. Litterfall P content in
black spruce averaged only 0.2 kg P-ha"1 as com-
pared to 5.3 kg P-ha"1 for paper birch (Van Cleve,
Oliver et al. 1983). Similarly, tamarack foliar P in-
versely correlates with site wetness and positively
correlates with specific conductivity, a measure of
dissolved ions (minerotrophy), the latter perhaps
accounting for a finding of lower tamarack foliar P
in a bog than in a fen (Tilton 1977, 1978).
Leaching and Mineralization: Two mecha-
nisms, leaching and mineralization, liberate stored
Water Quality Functions
PO4-P from biomass, sometimes making wetlands
seasonal sources of PO4-P even when they are sinks
for TP (e.g., Gehrels and Mulamoottil 1990). Leach-
ing loss of P from black spruce foliage is smaller
than that from several other taiga trees (Chapin and
Kedrowski 1983). Such loss accounted for only 0.01
to 0.04% of total foliar nutrient concentration in a
Wisconsin mire (Tyrrell and Boerner 1987).
Phosphate leaches from fresh litter in wetlands,
but older litter may accumulate P (van der Valk et al.
1979), roughly paralleling accumulation of organic
matter (Miller et al. 1979). Pools of TP in interior
Alaska black spruce stands (Table 20) are >3 times
that of aboveground tree components (Van Cleve,
Oliver et al. 1983). Leaching removed 3 to 4 times
more P from these stands than was added by precipi-
tation (Table 20).
Table 19. Phosphorus concentrations and pools in organic and mineral layers of several taiga black
spruce stands.
Site Type and
Location
Upland black
spruce - Alaska
Upland black
spruce - Alaska
Spruce-lichen
woodland - Quebec
Spruce-lichen
woodland - Quebec
Concentration
(ppm)
NA1
1.7to20.82
11.6to26.63
,4.2 to 6.4
Pool Size
(kg P-ha-1)
96
NA
0.21 to 0.49
NA
Comment
Organic layer TP
Mineral soil extractable P
increased with depth up to 0.15 to
0.30m
Organic layer available P
Mineral soil available P
Source
Troth et al.
(1976)
Troth et al.
(1976)
Moore
(1980).
Moore
(1980).
1. NA = not available.
2. Extractable P presumably is PO4-P.
3. Available P presumably is PO4-P.
Table 20. Phosphorus-related characteristics of interior Alaska black spruce stands.
Variable
Biomass (kg-ha"')
TP Pool (kg P-ha"')
Exchangeable P1 (kg P-ha"1)
P Input by Precipitation (kg P-ha"1)
P Output by Leaching (kg P-ha"')
P Mineralization Rate2 (kg P-ha"'-yr"')
P Turnover Time (yr)
Quantity
76,460
73
0.80
0.05 to 0.07
0.20
1.5 to 1.8
99
Source
Van Cleve, Oliver et al. (1983)
Van Cleve, Oliver et al. (1983)
Van Cleve, Oliver et al. (1983)
Van Cleve, Oliver et al. (1983)
Van Cleve, Oliver et al. (1983)
Flanagan and Van Cleve (1983)
Van Cleve, Oliver et al. (1983)
1. Presumably PO4-P.
2. White spruce and black spruce stands.
53
-------
Functional Profile of Black Spruce Wetlands in Alaska
Organic decomposition mineralizes PO4-P at
rates that may increase under anaerobic conditions
(Gersper et al. 1980). Decomposition rates vary in
response to type of litter, soil temperature, and avail-
able energy sources for decomposers (Flanagan
1986, Van Cleve and Yarie 1986). High-nutrient lit-
ter decomposes more quickly than low-nutrient lit-
ter (Flanagan and Van Cleve 1983). Needles of black
spruce and the lichen Cladina stellaris decompose
more slowly than leaves of resin birch in a Quebec
spruce-lichen woodland, but the lichen retains more
Pthan does black spruce (Moore 1983). Adding P to
black spruce litter does not directly increase soil res-
piration, however (Moore 1981, Flanagan 1986).
Low soil temperatures and poor litter quality give
black spruce the lowest decomposition rates of taiga
forest stands (Moore 1981; Van Cleve, Oliver et al.
1983). Taiga spruce stands (black and white) miner-
alize P (Table 20) at rates 2 to 3 times lower than
deciduous stands despite similar pool sizes
(Flanagan and Van Cleve 1983). Turnover time for P
in black spruce stands (Table 20) is more than 5
times as long as mean P turnover time in deciduous
stands (Van Cleve, Oliver et al. 1983).
Black spruce litter resists P mineralization, in
part, because insufficient energy may be available to
microorganisms responsible for decomposition.
Added glucose increased respiration rates of black
spruce litter by a factor of 3.8; available P also in-
creased (Flanagan 1986). Low mineralization rates
suggest that once transformed to organic form, P is
effectively retained in BSWs. A black spruce bog in
Minnesota annually retained 60% of DRP and 61 %
of the largely organic remaining P fractions in run-
off (Verry and Timmons 1982).
Phosphorus release by disturbances of black
spruce ecosystems also demonstrates significant
storage in biomass: available P in organic horizons
of burned, nonpermafrost black spruce plots (3.259
to 5.160 kg-ha'1) greatly exceeded a control (0.763
kg-ha'1) (Viereck et al. 1979); mined bogs discharged
greater concentrations of total dissolved P (TDP)
than did undisturbed bogs (Moore 1987); and logged
black spruce stands on mineral soils showed in-
creased TP and PO4-P in runoff (Nicolson 1988).
Timber removal followed by burning or removing
50% or 100% of the forest floor did not consistently
affect PO4-P in the soil solution, although the high-
est concentration (-140 (J-g-L"1) occurred in one
scorched plot in the year of disturbance, and removal
of the forest floor tended to depress PO4-P (Van
Cleve and Dyrness 1983&).
Functional Summary
Black spruce wetlands perform the nutrient-
transformation function for N and P, tending to make
inorganic forms less available, and are sinks for nu-
trient elements contained in accumulating organic
matter. Mineralization of organic N to easily-assimi-
lated NH4-N dominates N transformations in BSWs,
although at lower rates than occur in nonwetland
communities, and is followed by much smaller
moss- and lichen-associated cyanobacterial fixation
in ombrotrophic wetlands and by sweetgale- and al-
der-associated symbiont fixation of unknown mag-
nitude in minerotrophic wetlands. Nitrification
appears largely absent, but denitrification may occur
at low levels in minerotrophic BSWs where bacterial
denitrifiers are more abundant than in ombrotrophic
wetlands. Microbes responsible for nitrification and
denitrification are present in BSWs and can respond
to addition of appropriate substrates.
Adsorption of PO4-P to Fe-rich peats and uptake
by living organisms appear to dominate P transfor-
mations in BSWs, where shrubs cycle a dispropor-
tionately large share of P. Mineralization of organic
P to PO4-P occurs in BSWs but at much lower rates
than in deciduous forests. Chemical precipitation of
PO4-P probably is limited by the acidity and anaero-
bic conditions characteristic of ombrotrophic BSWs
but could tie up P in minerotrophic wetlands with
higher pH and potentially more aerobic conditions.
Accumulating organic matter generally accompa-
nies transformations that immobilize nutrients in
BSWs. Wetlands exhibiting a predominance of pro-
duction over decomposition (e.g., those with thick
moss layers or substantial litter accumulation) may
indicate transformations that reduce nutrient avail-
ability. Highly oxidized surfaces may indicate re-
duced capability for nutrient immobilization.
Ombrotrophy may indicate N fixation by
cyanobacteria associated with mosses, particularly
Sphagnum spp., and the lichens Nephroma spp. and
Peltigera spp., and also may indicate modest rates of
P adsorption and nutrient uptake. Iron-rich peats in
ombrotrophic BSWs indicate potential P adsorption,
but at lower rates than occur in calcareous (highly
minerotrophic) wetlands. The vegetation of
54
-------
Water Quality Functions
ombrotrophic BSWs indicates nutrient transforma-
tion through organismal uptake, although at lower
rates than found in minerotrophic wetlands.
Minerotrophy may indicate high rates of nutrient
mineralization and organismal uptake of nutrients;
denitrification; and, in some cases, N fixation by
symbionts of alder and sweetgale, P precipitation, or
high rates of P adsorption in BSWs. Minerotrophic
wetlands have higher pH values, higher base ele-
ment status, more easily decomposed vegetation
(e.g., sedges), vegetation adapted to high nutrient
uptake, and thus shorter turnover times for nutrients
than do ombrotrophic wetlands. Denitrification, to
the small extent that it occurs in taiga BSWs, is fa-
vored by pH > 5.5. Transformation of Pby chemical
precipitation is unlikely in ombrotrophic BSWs and
anaerobic conditions but could occur in
minerotrophic BSWs, particularly if well aerated.
Minerotrophic BSWs containing marl may indicate
high rates of P adsorption because peat of calcareous
fens apparently adsorbs more P than does bog peat.
Functional Sensitivity to Impacts
The nutrient-transformation function of BSWs is
sensitive to placement of fill, which buries the veg-
etation, soil, water, and associated microbes respon-
sible for nutrient transformations. Transformations
occur at specific rates, which may be expressed on a
unit-area basis. The impacts of fill placement on
nutrient transformation in BSWs thus are at least
proportional to the area filled. Fill that changes wet-
land chemistry, residence times for nutrients or wa-
ter, or biota necessarily has nonlinear impacts that
may be greater than indicated by the area of wetland
loss.
Establishing dense vegetation, including N-fixing
species, on fill surfaces could mitigate some fill-in-
duced impacts by assimilating N and P in overland
flow or atmospheric deposition and by fixing atmo-
spheric N but is unlikely to be consistent with pur-
poses for placing fills. Mineralization of nutrients
and adsorption of P would occur only if substantial
amounts of organic matter were spread or developed
on a fill surface. Nitrification, an aerobic process,
might occur on a revegetated fill, but denitrification,
an anaerobic process, probably would not.
The nutrient-transformation function of BSWs is
less sensitive to drainage than to placement of fill but
lower water tables and increased aeration of sub-
strates would alter nutrient transformations. Assum-
ing vegetation were left intact, increased rates of
primary production and nutrient uptake by plants
and increased abundance of lichens supporting N-
fixing phycobionts might occur following drainage.
Increased production likely would be accompanied
by larger increases in decomposition, net loss of or-
ganic matter, and increased mineralization of nutri-
ents.
Acid-inhibited nitrification, denitrification, and
chemical precipitation of P probably would be little
affected by drainage of ombrotrophic BSWs, but ni-
trification and P precipitation could increase in
drained minerotrophic wetlands due to more oxidiz-
ing conditions, at least until drained surfaces became
ombrotrophic and acidic. On-site mitigation of al-
tered patterns of nutrient transformation in drained
BSWs does not appear possible without restoring
lowered water tables to their original positions.
CONTAMINANT REMOVAL
Wetlands that remove contaminants from the
water, a water quality function, can be viewed as
toxicant sinks or toxicant reservoirs (Kraus 1988).
Contaminants including heavy metals and organic
compounds (e.g., pesticides or petroleum hydrocar-
bons) enter long-term sinks, reside for shorter peri-
ods in plant tissues or sediments, or degrade to less
toxic forms via processes such as adsorption, pre-
cipitation, microbial metabolism, and plant uptake
(Kadlec and Kadlec 1979, Sather and Smith
1984:13-14, Elder 1988, Ma and Yan 1989). These
processes often reduce contaminant concentrations
in wetland outflows. The following discussion ad-
dresses the functioning of BSWs with respect to
uptake and storage of metals in plant tissues, nutri-
ent immobilization, buffering capacity against atmo-
spheric deposition of acids, and ability to degrade
organic contaminants.
Metal Uptake and Storage
Vascular and nonvascular plants assimilate met-
als (Lee et al. 1984, Kraus 1988, Lan et al. 1992) that
enter wetlands by atmospheric deposition, surface or
subsurface flow of water, or wastewater discharge.
The high surface area-to-mass ratios of mosses make
them efficient traps for materials deposited from the
atmosphere (Santelmann and Gorham 1988); mosses
have been used as biomonitors of metal pollution for
55
-------
Functional Profile of Black Spruce Wetlands in Alaska
>20 yr (Wegener et al. 1992). Accumulation of ele-
ments by mosses occurs by cellular uptake, ex-
change of ions, and adherence of particulate matter
to plant surfaces, with the last mechanism most im-
portant for retention of lead (Pb), Cd, Fe, and Al
(Malmer 1988). Sphagnum mosses accumulate air-
borne metals, especially Mn, to a greater extent than
do Cladina (Cladonia) lichens in the same bogs
(Pakarinen 1981) and may have significant potential
for uptake of contaminants in BSWs.
Wet and dry deposition of particulates is the only
route for metals to enter undisturbed ombrotrophic
BSWs. Metal particulates emanating from human
activities, such as smelting of metal ores, deposit in
peatlands at varying distances from emission sources
and can be detected by analysis of organic soils or
Sphagnum mosses (Pakarinen 1981, Brown et al.
1987). Concentrations of Al, Fe, zinc (Zn), Cd, Pb,
and copper (Cu) increase with age of Sphagnum tis-
sues (Malmer 1988), with correlations between Pb,
Fe, and Zn or between arsenic, Cd, Pb, and Zn noted
in several regions (Pakarinen 1981, Santelmann and
Gorham 1988). Mosses in Swedish bogs preferen-
tially retained "Mn>Cu>Al, Fe, Zn, Cd, Pb" relative
to atmospheric deposition (Malmer 1988:113), but
retention of Zn tends to be low in Sphagnum
(Glooschenko and Capobianco 1979 in Malmer
1988).
Mosses in minerotrophic wetlands can accumu-
late metals contained in metal-rich groundwater or
surface runoff. Metal distributions in minerotrophic
mires can vary with depth in response to chemical
reduction and binding to peat (e.g., Elomaa 1987).
Lee et al. (1984) reported that springs with high Zn
and sulfate concentrations and high alkalinity sup-
ported mosses with tissue concentrations of Pb, Cd,
and Zn ranging from 3 to 5 orders of magnitude over
concentrations in springwater emanating from an ore
body. Tissue concentrations, caused by ion exchange
and entrapment of precipitates, varied by species of
moss and by location within moss tissue.
Natural or constructed wetlands containing
mosses can treat wastewater containing metals. Sph-
agnum mosses provide a large below-water biomass
for entrapment of particulates in wastewater treat-
ment systems (Skousen and Sencindiver 1988); re-
move Fe, Mn, Al, Cd, nickel (Ni), and Zn by cation
exchange (Fennessy and Mitsch 1989, Wieder
1990); and acidify their surroundings to enhance
uptake of Pb by some vascular plants, although de-
pressing uptake by others (Vedagiri and Ehrenfeld
1991). The cation exchange capacity of Sphagnum
peat in one test was 1,320 (J-Eq-g-1 (Wieder 1990).
Thiobacillus ferrooxidans regenerates saturated ex-
change sites by oxidizing Fe so that it precipitates,
freeing the sites to bind additional ions (Fennessy
and Mitsch 1989).
Vascular wetland plants also remove metals from
water. Roots and rhizomes of emergent vegetation
growing in temperate estuarine marshes generally
accumulate higher concentrations of Cu, Ni, Cd, and
Pb than do stems and leaves (Kraus 1988). Cattails
effectively take up Pb and Zn, with higher concen-
trations occurring in roots than in shoots (Lan et al.
1992), although adsorption and microbial activity,
rather than plant uptake, may be the mechanisms
responsible for most removal of Fe and Mn from
mine wastewater (Fennessy and Mitsch 1989). Mac-
rophytes also probably enhance chemical precipita-
tion of metals and their sorption to sediment by
providing organic matter to the system, lowering re-
dox potentials, and providing a substrate for micro-
bial populations (Skousen and Sencindiver 1988,
Lan et al. 1992). Vegetation of BSWs is a source of
organic matter, should lower redox potentials, and
should provide microbial substrates in the same way
as does marsh vegetation, implying potential for
metal uptake and storage.
Plaque made up of Fe oxides and hydroxides
forms on the roots, culms, or rhizomes of emergent
vascular plants such as cattails and sedges, where it
can coprecipitate and adsorb metals such as Mn, Cu,
Zn, and Ni (Crowder et al. 1987). Plaques also form
on the roots of plants in acid bogs (Armstrong and
Boatman 1967 in Crowder et al. 1987), and Fe and
Mn oxides occur on the flooded roots of black
spruce (Levan and Riha 1986). Plaque formation is
inversely related to the peat content and CO3 concen-
tration of wetland soils, perhaps because peat itself
binds metal ions (Crowder et al. 1987).
Coprecipitation of toxic metals in Fe plaques might
occur in BSWs, although the high organic matter
contents of these wetlands presumably would limit
plaque formation.
Nutrient Immobilization
The balance between net primary production and
decomposition controls peat accumulation in mires
56
-------
Water Quality Functions
(Clymo 1983, Damman 1987), although decomposi-
tion may be the most important factor (Johnson
1987). Accumulation of organic matter in mires re-
moves elements from nutrient cycles as peat depth
increases (Moore and Bellamy 1974:86) and the ris-
ing boundary of the catotelm imposes anaerobic con-
ditions that essentially halt decomposition (Damman
1987). A Minnesota bog retained 55% of entering
waterborne nutrients within soils and vegetation
(Verry and Timmons 1982), with an estimated 7 to
12.2 kg N-ha-'-yr1 entering the anaerobic catotelm
where it is essentially immobilized (Urban and
Eisenreich 1988). Similarly, Alaska's BSWs accu-
mulate organic matter and immobilize nutrients be-
cause low soil temperatures, poor litter quality, and
anaerobic conditions hinder decomposition and nu-
trient mineralization. Permafrost enhances nutrient
immobilization, even in mineral soils (Van Cleve,
Dyrness et al. 1983), as frost tables rise in response
to thickening organic mats.
Mires in subarctic and boreal wetland regions
trend toward peat plateaus and palsas in the zone of
discontinuous permafrost and toward treed bogs in
continental nonpermafrost areas, although reversion
to earlier developmental stages can occur with dis-
turbance or changing environments (Zoltai, Tarnocai
et al. 1988; Zoltai, Taylor et al. 1988). Invading
ombrotrophic vegetation often covers fen peats de-
posited in nonpermafrost environments and induces
permafrost formation that thrusts surfaces of palsas
and peat plateaus above surrounding fens by forma-
tion of ice lenses and volumetric expansion of frozen
saturated peat (Zoltai and Tarnocai 1975). Long-
term rates of accumulation in deep, compacted peat
of Canadian taiga mires range from 28 to 106
mm-100 yr1, with an average rate of 50 mm-100
yr1 (Zoltai, Taylor et al. 1988). Uncompressed, fibric
surface peats naturally accumulate at greater rates:
Sphagnum hummocks in a forested Minnesota bog
thickened by 400 mm in 86 yr (Urban and Eisenreich
1988) and a paludified slope of interior Alaska de-
veloped 410 to 710 mm of Sphagnum peat in < 185
yr(Heilman 1966, 1968).
Regional climatic changes may have little influ-
ence on long-term peat formation in basin wetlands
(Warner and Kubiw 1987), which develop by
terrestrialization or infilling of aquatic environ-
ments with peat (Sjors 1983) to thicknesses of >6 m
(Zoltai, Taylor et al. 1988) over many thousands of
years (Table 21). Unidirectional successional se-
quences are uncommon, however (Heinselman
1963). Primary mires, which occur with the growth
of peat-forming vegetation directly on wet mineral
soils (Sjors 1983), appear susceptible to climatic
change (Table 21), as do peat plateaus and palsas.
Raised permafrost bogs do not grow indefinitely
(Tallis 1983): peat accumulation can cease (Table
21) after raised surfaces establish (e.g., Zoltai and
Tarnocai 1975), probably because the surfaces dry
(Zoltai, Tarnocai et al. 1988), and peat surfaces can
subside if permafrost thaws (e.g., Kershaw and Gill
1979). Thawed bogs may exhibit renewed peat
Table 21. Periods of active peat accumulation in several North American and Asian mires.
Wetland Type and Location
Peat plateau bogs -
northwestern Canada
Kettle bog - Ontario
Primary black spruce/
Sphagnum bog - Quebec
Black spruce mire - Alaska
Paludified river terrace
(treeless) - western Siberia
Basal Peat Age
(yr BP)
-10,000 to -6,000
-8,000
-5,200
-3,500
>5,000
Cessation of
Active Peat
Accumulation
(yr BP)
-2,700
0
-1,100
-1,400'
7
Source
Zoltai and Tarnocai (1975)
Warner and Kubiw (1987)
Payetteetal. (1986)
Hamilton etal. (1983)
Gorozhankina(1991)
1. Renewed peat growth has occurred from -400 yr BP to the present.
57
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Functional Profile of Black Spruce Wetlands in Alaska
growth in collapse scar fens (Zoltai, Tarnocai et al.
1988), a process that may cause repetitive cycles of
mire development on river flats of interior Alaska
(Druryl956).
Long-term accumulation produces deep peat
soils in lowland depressions (mires) of interior
Alaska (e.g., Rieger et al. 1963, Rawlinson and
Hardy 1982). Migrating rivers can erode such depos-
its into aquatic ecosystems where sedimentation can
rebury organic material or microbial decomposition
can release sequestered nutrients. The time scale for
river erosion of peat deposits, on the order of hun-
dreds or thousands of years, makes lowland black
spruce mires long-term nutrient sinks.
Fire may limit peat accumulation in
nondepressional BSWs, as shown by depth and age
of organic material (e.g., Heilman 1968). In North-
west Territories, Canada, fire frequency in upland
stands may be twice that of lowland black spruce-
Sphagnum /Mscw/rz-Ericaceae communities
(Jasieniuk and Johnson 1982). Viereck (1983) hy-
pothesized that permafrost black spruce forests (i.e.,
BSWs) might develop into treeless Sphagnum mires
in the absence of fire.
Moderate to heavy burns release immobilized nu-
trients, increasing total N, TP, and available P in for-
est floors (Dyrness et al. 1986). Fire volatilizes N
and increases K in streams draining burned stands
(Viereck and Schandelmeier 1980:23,35). Rapid re-
establishment of vegetation following fire presum-
ably retains most nutrients on site, however (Dyrness
et al. 1986). The combined effects of nutrient immo-
bilization by peat accumulation in nondepressional
BSWs and release by fire appear to favor immobili-
zation.
Buffering Capacity
Wetlands can buffer excessive acidity or alkalin-
ity. Acidic anthropogenic compounds that adversely
affect aquatic ecosystems are the chief concern in
this context (e.g., Kortelainen and Mannio 1988).
Kessel-Taylor and Anderson (1987) proposed that
rich fens should have a high capacity to buffer acid
deposition based on their characteristically low acid-
ity (pH > 6), high concentration of cations, high bi-
carbonate (HCO3) buffering capacity, and flowing
waters; poor fens should show a low capacity based
on pH concentrations between 4.5 and 6.0, low alka-
linity, and slow-moving or standing water; and bogs
should have a moderate capacity based on ample
organic acids and Al, which act as buffers and also
reduce SOr In contrast, Holowaychuk et al. (1986 in
Kessel-Taylor and Anderson 1987) proposed that
poor fens buffer acid deposition better than do bogs,
but apparently did not consider buffering by organic
acids and Al.
Physical and chemical characteristics of organic
horizons of forest soils affect buffering capacities
(Mahendrappa 1986). Presumably, these characteris-
tics are influenced by vegetation and are as true of
forested wetlands as of other forests. Tissue
homogenates of black spruce foliage poorly buffered
acids, tamarack moderately buffered acids, and La-
brador-tea strongly buffered acids (Pylypec and
Redmann 1984). Black spruce and Labrador-tea of-
ten occur together, but their combined effect on buff-
ering capacities of BSWs is not clear. Tamarack may
enhance potentially poor buffering capacities of
weakly minerotrophic BSWs for acid deposition.
Contaminant Degradation
Chemical reactions and microbial activity can de-
grade contaminants entering wetlands and thus
lower contaminant concentrations in wetland dis-
charges. Long contact times between water and wet-
land substrates and diverse microbial communities
favor retention of contaminants by wetlands (Elder
1988) and also should favor contaminant degrada-
tion. Contact between contaminants and solid sur-
faces supporting bacteria and fungi promote
chemical and microbial transformations of sub-
stances in the water column (Kadlec 1988).
Black spruce wetlands provide significant con-
tact between incoming water and solid substrates.
Subsurface flow in ombrotrophic wetlands places
entrained contaminants in nearly constant contact
with peat surfaces, which, for Sphagnum peat, have
high cation exchange capacities (Clymo 1983), po-
tentially enhancing binding of certain organic com-
pounds. Minerotrophic peats (e.g., peats derived
from cotton grass [Clymo 1983]) may have lower
cation exchange capacities than ombrotrophic peats,
but weakly minerotrophic wetlands generally have
low flows favoring long contact times.
Low temperatures and anaerobic conditions may
hinder contaminant degradation in BSWs. Although
a BSW immobilized experimental spills of crude oil
via the absorptive capacity of the thick organic layer
55
-------
Water Quality Functions
(Johnson et al. 1980), volatilization of lighter hydro-
carbon fractions accounted for most changes in com-
position of the crude during the first 2 yr following
the spills (Jenkins et al. 1978). Initially, populations
of heterotrophic bacteria increased, but filamentous
fungi decreased (Sparrow et al. 1978). Microbial
biomass remained depressed after 10 yr, with large
amounts of crude remaining at the spill sites (Spar-
row and Sparrow 1988).
Functional Summary
Black spruce wetlands perform the contaminant-
removal function by taking up and storing metals,
immobilizing nutrients, and, in some cases, buffer-
ing inputs of acids. Black spruce wetlands do not
effectively degrade hydrocarbons and, by extension,
presumably do not effectively degrade other toxic
organic compounds. Uptake and storage of metals
occur in mosses, particularly Sphagnum spp., by
cellular uptake, ion exchange, and trapping of par-
ticulates. Vascular plants concentrate metals in roots
and rhizomes. Coprecipitation of toxic metals during
formation of Fe plaques on belowground parts of
wetland plants also removes contaminants from cir-
culation.
Black spruce wetlands immobilize nutrients by
accumulating organic matter. Moss nutrient pools
become unavailable to vascular plants as accumulat-
ing peat renders subsurface layers anaerobic and as
permafrost tables rise. Peat accumulation can con-
tinue for thousands of years in lowland basin mires
until river erosion exposes peat to degradation. Fre-
quent fires appear to limit peat accumulation in
nondepressional BSWs. Nutrients released but not
volatilized by fire largely remain on site and supply
rapid re-establishment of vegetative cover.
Highly minerotrophic BSWs should strongly
buffer acid deposition, but weakly minerotrophic
and ombrotrophic wetlands should have only low to
moderate buffering capacities. Minerotrophy, per-
haps supplemented by the presence of acid-buffering
vegetation such as tamarack and Labrador-tea, thus
indicates acid buffering capacity.
Ombrotrophic and minerotrophic BSWs both
support plant species and processes potentially ca-
pable of metal uptake or storage; therefore, species-
or community-based indicators of this function are
unlikely. In contrast, visually-apparent, rapidly accu-
mulating organic matter indicates high nutrient im-
mobilization whereas stagnant or highly-oxidized
organic matter, such as might occur on ombrotrophic
peat plateaus and palsas, indicates little immobiliza-
tion. Peats of minerotrophic wetlands tend to be
more decomposed than peats of ombrotrophic wet-
lands, perhaps indicating that minerotrophic BSWs
are slightly less effective than nonstagnant
ombrotrophic BSWs for nutrient immobilization.
Functional Sensitivity to Impacts
The contaminant-removal function of BSWs is
sensitive to placement of fill. Fill covers vegetation
responsible for metal uptake and storage and immo-
bilization of nutrients and diminishes the surface
area of buffering systems. Calcareous fill might
buffer acid deposition on fill surfaces, however.
Warm, aerobic fill surfaces might degrade organic
contaminants more rapidly than cold, anaerobic soils
of BSWs, if the contaminants could contact the el-
evated fill surface.
Re-establishment of wetland vegetation and peat-
forming systems on fill surfaces might mitigate di-
minished wetland capability for contaminant
removal but is unlikely to be consistent with the pur-
poses for fill placement. Such created wetlands
should incorporate plant species known to take up
metals, such as Sphagnum mosses or cattails; resist
decomposition to enhance nutrient immobilization;
and buffer acidity. Calcareous substrates or ground-
water inputs might be necessary to enhance acid
buffering capacity, as well.
The contaminant-removal function of BSWs is
less sensitive to drainage than to fill. Sensitivity
should increase with drainage effectiveness. Partial
drainage would allow wetland plants capable of tak-
ing up and storing metals to persist but would in-
crease the depth and warmth of the aerobic zone,
initially increasing decomposition and nutrient min-
eralization and potentially releasing some stored
metals. Thorough drainage (i.e., conversion to up-
land conditions) would eliminate metal-storing
plants such as mosses and cattails and accelerate
contaminant release from decomposing organic mat-
ter but might mineralize sufficient nutrients to pro-
mote microbial degradation of hydrocarbons and
other organic contaminants.
Surfaces of partially-drained minerotrophic wet-
lands eventually may develop ombrotrophic vegeta-
tion resistant to decomposition and thus regain some
59
-------
Functional Profile of Black Spruce Wetlands in Alaska
capacity for storing metals and immobilizing nutri-
ents. Such surfaces should have diminished acid
buffering capacities in strongly minerotrophic wet-
lands but possibly increased capacities in weakly
minerotrophic wetlands from increased buffering by
Al and organic acids. Partially draining ombro-
trophic wetlands should have little effect on their
acid buffering capacities.
Restoring water tables of BSWs to pre-distur-
bance elevations would mitigate the effects of drain-
age on the contaminant-removal function.
DATA GAPS
Data gaps exist with respect to the water quality
functions of Alaska's BSWs. Additional studies of
sediment retention, nutrient uptake, nutrient transfor-
mation, and contaminant removal under subarctic
conditions are warranted.
Sediment Retention
Scientists have measured discharges and concen-
trations of TSS exiting well-defined watersheds con-
taining BSWs in relatively steep terrain (e.g.,
Chacho 1990), but these sediment yields derive from
a variety of source areas. Direct measurements (e.g.,
mass balance studies) of sediment retention by indi-
vidual BSWs, particularly in lowland terrain, are
needed but appear not to have been made.
Nutrient Uptake
Detailed ecologic studies have characterized nu-
trient uptake in largely ombrotrophic black spruce
forests and woodlands on Alaska permafrost sites,
although these sites have been from the drier end of
the wetland spectrum (e.g., Van Cleve, Oliver et al.
1983). Nutrient uptake in the wettest ombrotrophic
BSWs (e.g., basin bogs) and in most minerotrophic
BSWs has received little study. Minerotrophic
BSWs are important because they have higher prob-
abilities of receiving waterborne nutrients than do
ombrotrophic wetlands and their vegetation should
be adapted for nutrient uptake. Nutrient uptake
might best be studied via experimental fertilization
or controlled application of high-nutrient wastewa-
ter and measurement of changes in tissue nutrient
concentrations and quantities, rates of photosynthe-
sis, and biomass. These quantities tell more about the
fate of influent nutrients than does the mere differ-
ence between influent and effluent nutrient loads.
Nutrient Transformation
Scientists have studied N fixation and mineral-
ization; P uptake, leaching, and mineralization; and
the significance of P uptake by shrubs in relation to
their biomass in ombrotrophic black spruce stands
and bogs, but comparable studies are not available
for minerotrophic BSWs. Phosphorus precipitation
and adsorption, nitrification, and denitrification have
received little study in taiga BSWs, regardless of
trophic status. All nutrient transformations for N and
P thus require quantification in minerotrophic
BSWs, and selected transformations such as nitrifi-
cation, denitrification, and the relative roles of peat
and Fe complexes in P adsorption, also require quan-
tification in ombrotrophic BSWs.
Contaminant Removal
Metal uptake and storage by certain plants is rea-
sonably well-documented for metal-tolerant mosses
in bogs and in metal-rich fens associated with ore
bodies and for selected vascular plants in marshes,
although metals are toxic to many other vascular
plants and to algae (J. LaPerriere, Univ. Alaska, pers.
commun.). Formation of Fe plaques and
coprecipitation and adsorption of toxic metals on
belowground parts of marsh plants also have been
described. Vascular vegetation of minerotrophic
BSWs also may take up metals and form plaques,
but this has not been documented and should receive
study.
Peat accumulation in taiga mires has received
substantial study in Canada but little in Alaska. Stud-
ies of nutrients tied up in organic matter of Alaska's
ombrotrophic black spruce stands are available, but
little information exists for minerotrophic BSWs.
Controls on peat accumulation in BSWs, including
climatic and microclimatic factors (e.g., Horn 1986),
the process of paludification, fire, and the frequency
of peat erosion by fluvial processes, deserve further
attention. In addition, assumptions used in Canadian
reviews to rate the acid buffering capacities of mires
should be verified for Alaska's BSWs.
Functional Sensitivity to Impacts
Data gaps exist with respect to the sensitivity of
certain water quality functions of BSWs to the im-
pacts of drainage and placement of fill. That fill ef-
fectively eliminates the sediment-retention,
nutrient-uptake, nutrient-transformation, and con-
60
-------
Water Quality Functions
taminant-removal functions of covered areas in
BSWs is relatively self evident and requires little
study. In contrast, although drainage at least tempo-
rarily reduces sediment retention in bogs and in-
creases decomposition in mires, scientists have
obtained little information about the effects of drain-
age on the other water quality functions of BSWs.
Drainage presumably increases the availability of
nutrients to wetland plants, and drained wetlands
may continue to remove contaminants at reduced,
but unquantified, levels. Drainage effects on nutrient
uptake and transformation in BSWs could be docu-
mented by obtaining water and nutrient budgets, net
primary production, biomass, and tissue nutrient lev-
els before and after drainage of experimental plots.
Effects of drainage on contaminant removal might
be documented by comparing drained and undrained
BSWs with respect to plant community composition
and experimentally-determined capacities of such
communities for metals uptake and storage and with
respect to decomposition and net primary production
and thus capacities to immobilize nutrients by peat
accumulation. Finally, experimental acidification of
undrained and drained minerotrophic wetlands
might be used to verify buffering capacities.
61
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Functional Profile of Black Spruce Wetlands in Alaska
GLOBAL BIOGEOCHEMICAL FUNCTIONS
Nitrogen, sulfur (S), and C participate in global
biogeochemical cycles (Mitsch and Gosselink
1993:525-527). Molecules containing these ele-
ments not only cycle within wetlands but also pass
between wetlands and the atmosphere where some
affect global climate. This profile discusses N fixa-
tion and denitrification as water quality and ecologic
functions, but little information on S cycling in mires
or mire-like wetlands appears in the literature and
consequently is not addressed herein. Although C
cycling and storage might be considered water qual-
ity or ecologic functions of wetlands, based on the
role of C as a nutrient and the importance of peat ac-
cumulation in long-term storage of other nutrients
and contaminants, this profile separately addresses C
cycling and storage because of their importance to
anthropogenic air chemistry and removal of atmo-
spheric C in relation to global warming.
CARBON CYCLING AND STORAGE
Carbon is stored, released, and transformed
through primary production, decomposition, and
other biologically-mediated processes in global bio-
geochemical cycles. Wetlands contain -12% of the
global soil pool of organic C (Lugo, Brown et al.
1990) and thus are important for C cycling and stor-
age. At least 500 million ha of global wetlands accu-
mulate C as peat (Maltby 1986:51), many in arctic,
subarctic, and boreal portions of North America, Eu-
rope, and Asia (Mitsch and Gosselink 1993:368-
371). Canada alone has an estimated 111.3 million
ha of peatlands (Zoltai 1988), constituting "one of
the few terrestrial ecosystems where C is stored for
thousands of years" (S. C. Zoltai, Can. For. Serv.,
pers. commun). Peat therefore acts as a sink for at-
mospheric C fixed by photosynthesis (Friedman and
DeWitt 1979; Malmer 1988; Lugo, Brown et al.
1990).
Carbon transformations occurring in wetlands in-
volve changes in phase, such as release of carbon
dioxide (CO2) and methane (CH4) to the atmosphere
(Mitsch and Gosselink 1993:134-136); shifts in
chemical equilibria between dissolved CO2, HCO3,
and carbonate (CO3), which make up total inorganic
C (Wetzel 1983:202-204); precipitation of CO3
(Wetzel 1983:205-207); cycling between inorganic
and organic C via photosynthesis, respiration, and
fermentation; and changes in particle size of organic
C. Organic C occurs in dissolved (DOC) and particu-
late (POC) forms in aquatic systems and the soil
solution, although these pools are minor in compari-
son to soil C (D. K. Swanson, Nat. Resour. Conserv.
Serv., pers. commun.).
Two major processes encompass C transforma-
tions in wetlands: primary production of biomass
and its subsequent decomposition. Photosynthesis
transforms inorganic C to carbohydrate, and subse-
quent metabolic processes, including heterotrophic
consumption, incorporate C in other organic com-
pounds. Community respiration and anaerobic de-
composition (fermentation) release compounds such
as CO2, lactic acid, and ethanol (Mitsch and
Gosselink 1993:135). Excluding imports and exports
of organic material, the balance between net primary
production and decomposition in a wetland deter-
mines whether or not it will function as a sink for C.
Primary Production
Plants assimilate atmospheric or dissolved CO2to
support photosynthesis, although some submersed
species (excluding mosses) can use HCO3 under ap-
propriate conditions (Wetzel 1983:217). Terminal
62
-------
Global Biogeochemical Functions
portions of Sphagnum mosses fix significant quan-
tities of atmospheric C in ombrotrophic mires
(Malmer 1988). Black spruce stands occurring on
permafrost soils, whether lowland or upland, accu-
mulate more forest floor organic matter than other
taiga forest types (Van Cleve, Oliver et al. 1983),
storing C in soil (Table 22) and aboveground tree
components (Table 23). In one such stand, Sphag-
num subsecundum allocated 70 to 76% of fixed C to
brown tissue over the growing season, and, along
with feathermosses and Polytrichum commune,
stored C in polysaccharides (Skre et al. 1983a).
Modeling indicates that taiga uplands of interior
Alaska, like other taiga regions, are a sink for CO2
(Bonan 1990a,fo). Based on large volumes of stored
peat, lowland mires also are C sinks. The mean C
content of mineral soils (Table 22) and mean esti-
mated C content of aboveground tree components
and forest floors (Table 23) suggest an average of
-137 metric tons C-ha~' in black spruce stands
sampled by Van Cleve, Oliver et al. (1983). The larg-
est mineral-soil C content reported for cold black
spruce stands (Table 22), combined with the largest
C content estimated for tree, root, and forest floor
biomass (Table 23), suggest that some permafrost
BSWs may store >200 metric tons C-ha'1
The competitive processes of net primary pro-
duction and decomposition determine wetland C bal-
ance, even with significant annual production of
biomass (Figure 9). Only the strings of a Quebec
northern ribbed fen accumulated C on an annual
basis (Figure 10). The rate of C gain for the fen
string compares favorably with other sites from Eu-
rope and North America: a range of 40 to 670 kg
C-ha-'-yr1 but most frequently 150 to 300 kg C-
ha-'-yr1 (Moore 1989). Some fen strings are BSWs.
Decomposition
Decomposition comprises leaching of substances
from dead organic matter, physical and biological
fragmentation of detritus, and oxidation of particu-
late organic matter by microorganisms (de la Cruz
1979). Anaerobiosis slows decomposition in BSWs
and thus is very important for preserving C (D. K.
Swanson, Nat. Resour. Conserv. Serv., pers.
commun.). In addition, lack of easily metabolizable
Table 22. Soil carbon contents of representative interior Alaska black spruce stands.
Site Type
Permafrost black spruce
Black spruce
Cold black spruce
Soil Carbon Content (metric tons-ha'1)
Organic
Layer
70.81
-20 to -75 '
NA5
Mineral
Soil2
39.81
?32,3
<90
Soil Profile
110.61
~90to~1504
NA
Source
Sparrow and Sparrow (1988)
Van Cleve, Oliver et al. (1983)
Viereck and Van Cleve (1984)
1. Values are total organic carbon (TOC).
2. Values are total carbon (TC).
3. Mean for multiple stands.
4. Sum of reported range of TOC for organic horizons and reported mean TC for mineral soil.
5. NA = not available.
Table 23. Combined carbon contents of aboveground tree components and forest floors of representative
interior Alaska black spruce stands based on biomass.
Site Type
Black spruce stands
Black spruce stand
Biomass
(metric tons-ha"1)
1272
~2403
Carbon Content1
(metric tons-ha"1)
-64
-120
Source
Van Cleve, Oliver et al. (1983)
Viereck and Van Cleve (1984)
1. Calculated from biomass assuming a biomass to C conversion factor of -50% (e.g., Moore 1989).
2. Mean value for multiple stands.
3. Includes root biomass.
63
-------
^p^^^
Functional Profile of Black Spruce Wetlands in Alaska
Annual Production
CO
CO
g
CO
Pools Flarks Strings
FEN COMPONENT
Figure 9. Net primary production for components of a northern ribbed fen in subarctic Quebec (Moore 1989).
Carbon Balance
Pools Flarks
FEN COMPONENT
Strings
Figure 10. Carbon balance for components of a northern ribbed fen in subarctic Quebec (Moore 1989).
64
-------
Global Biogeochemical Functions
substrates for fungi and other decay microorganisms
(Moore 1981, Flanagan 1986) and, more impor-
tantly, low soil temperatures slow decomposition in
organic horizons of black spruce stands (Moore
1981; Van Cleve, Oliver et al. 1983; Yarie 1983, Van
Cleve and Yarie 1986). Where permafrost is present,
decomposition of organic matter essentially ceases
below the permafrost table.
Black spruce wetlands often store C in forms that
resist degradation, even under aerobic processes.
Plants can allocate C to growth or to secondary me-
tabolites that function for defense against herbivores
(Bryant 1984:7-10, Bryant and Chapin 1986). In
ombrotrophic wetlands, slow-growth species such as
black spruce have a competitive advantage over de-
ciduous species with high nutrient requirements
(Chapin 1986, Brumelis and Carleton 1988). Slow-
growth species tend to accumulate C-based
antiherbivory compounds (Bryant et al. 1983) that
discourage nutrient losses to herbivory but also in-
hibit decomposition (Bryant and Chapin 1986).
Minerotrophic wetlands might be expected to
support easily-degraded, fast-growth plants. Al-
though fens sometimes have more highly degraded
peats than do bogs (Clausen and Brooks 1983/?), this
is not necessarily the case (P. H. Glaser, Univ. Minn.,
pers. commun.). Rates of decomposition vary by
type of litter, however, with woody species charac-
teristic of fen strings (e.g., leatherleaf) decomposing
slowly and herbaceous species characteristic of
pools (e.g., buckbean) decaying quickly (Moore
1989).
Although organic material decomposes slowly in
BSWs, some C escapes to the atmosphere. Respira-
tion and fermentation produce CO2 (Mitsch and
Gosselink 1993:134-136), and anaerobic decompo-
sition at low redox potentials produces CH4 (Lugo,
Brown et al. 1990). Carbon dioxide produced within
saturated peat exists in solution, but CH4 apparently
also exists in the gaseous phase (Buttler et al. 1991)
and lowers peat hydraulic conductivity by occluding
pore spaces (Brown and Overend 1993). Methane
may be oxidized to CO2 as it passes through aerobic
surficial peats (Mitsch and Gosselink 1986:103,
Moore 1989, Fechner and Hemond 1992, Moore et
al. 1994).
Water table height is inversely related (linear) to
CO2 evolution (Moore and Knowles 1989) and posi-
tively related (logarithmic) to CH4 evolution (Moore
and Knowles 1989). Ratios of CH4 to CO2 therefore
increase with depth (e.g., Dinel et al. 1988). Strings
of a northern ribbed fen evolved predominantly CO,,
pools evolved predominantly CH4, and flarks (near-
surface water table) evolved both gases (Moore
1989). Fen pools can emit much more CH4 per unit
area than nearby peat surfaces (Hamilton et al. 1994,
Rouletetal. 1994).
Matthews and Fung (1987) estimated that -60%
of global wetland emission of CH4 occurs from
northern peatlands, although recent estimates (e.g.,
Roulet et al. 1994) are lower. Soil temperature influ-
ences seasonal trends in CH4 emission (Whalen and
Reeburgh 1992, Klinger et al. 1994). Fens emit more
CH4 than do bogs (Svensson and Rosswall 1984,
Moore and Knowles 1989, Dise 1992), which emit
little (Moore and Knowles 1990, Moore et al. 1990,
Brown and Overend 1993, Moore et al. 1994). In
Alaska, Eriophorutn vaginatum tussocks and pond-
margin stands of Carex spp., settings found in
minerotrophic BSWs, produced more CH4 than did
intertussock depressions covered with Sphagnum
moss or detritus and elevated non-Sphagnum moss
areas (Whalen and Reeburgh 1992).
Several permafrost black spruce sites in Alaska
with seasonally high soil moistures consistently con-
sumed atmospheric CH4, as well as CH4 from experi-
mentally enriched atmospheres (Whalen et al. 1991).
Warmer, drier soils consumed more CH4 than cooler,
wetter soils (Whalen et al. 1991). It is not clear that
these sites were BSWs, but they indicate that drier
ombrotrophic BSWs may consume, rather than emit,
CH4.
Oxidation of stored C to CO2by fire also is im-
portant in interior Alaska where black spruce taiga
burns with a cycle of 50 to 200 yr (Viereck and
Schandelmeier 1980:12, Dyrness et al. 1989). Fires
tend to consume less accumulated organic matter on
wetter north-aspect slopes than on drier south-aspect
slopes (Van Cleve et al. 1991). Lowland BSWs with
high water tables presumably limit release of accu-
mulated C in a similar manner.
Functional Summary
Black spruce wetlands function to cycle and store
C, primarily by photosynthesis and decomposition.
Photosynthetic fixation of CO2 (primary production)
in BSWs is lower than in nonwetland forests, but
rates of decomposition also are low, leading to accu-
65
-------
Functional Profile of Black Spruce Wetlands in Alaska
mulation of C as organic matter. Decomposition re-
leases stored C as CH4 and CO2, and fire releases
CO2 as a combustion product, but saturated condi-
tions in BSWs minimize these losses as compared to
nonwetlands. Aerobic surface layers of ombro-
trophic BSWs may consume atmospheric CH4.
Black spruce wetlands thus are important sinks for
atmospheric C.
Active accumulation of organic matter indicates
C storage in BSWs. Highly decomposed organic ho-
rizons may indicate a neutral or negative C balance.
Wetlands with characteristically high water tables
and low redox potentials (often minerotrophic) indi-
cate potential CH4 emission whereas those with
aerobic surface layers (often ombrotrophic) indicate
potential CO, emission and CH4 consumption.
Functional Sensitivity to Impacts
The C cycling and storage functions of BSWs is
sensitive to placement of fill. Carbon cycling would
not occur on a barren fill surface. Establishing dense
vegetation on a fill surface could mitigate loss of C
fixation by wetland plants. Much fixed C in litter
would be lost to decomposition until (and if) conif-
erous forest and substantial moss cover became es-
tablished on the fill and soil temperature declined
sufficiently for permafrost formation, a process that
might take >200 yr in the taiga environment.
The effects of drainage on the C cycling and stor-
age function of BSWs are not clear. Surfaces of
minerotrophic wetlands should become ombro-
trophic following effective drainage, potentially low-
ering net primary production but also producing
woody litter more resistant to decomposition. Effec-
tive drainage should increase decomposition in both
ombrotrophic and minerotrophic BSWs and might
produce negative C balances. Less effective drain-
age, however, might allow C storage to continue.
Carbon dioxide evolution in drained wetlands should
increase at the expense of CH4 evolution. Fires po-
tentially would consume more accumulated organic
matter, with consequent release of stored C, in
drained than undrained BSWs.
DATA GAPS
Carbon transformations have been documented
in some BSWs of interior Alaska (e.g., Van Cleve,
Oliver et al. 1983) and in subarctic Canadian fens
(Moore 1989). Carbon fixation has received more
attention than decomposition and ombrotrophic
woodlands more attention than minerotrophic wet-
lands. Documentation of net C balance for a variety
of BSWs, as influenced by trophic status, commu-
nity composition, and hydrologic relationships, is
warranted given the importance of CO2 as a green-
house gas.
66
-------
ECOLOGIC FUNCTIONS
All wetland functions are, in a holistic sense, eco-
logic functions because wetland ecosystems encom-
pass all physical, chemical, and biological
phenomena (i.e., functions) occurring within ecosys-
tem boundaries. Nevertheless, this report narrowly
defines ecologic functions as those primarily derived
from biological processes, or from chemical pro-
cesses mediated by living organisms, but sometimes
supplemented by strictly physical or chemical com-
ponents: nutrient cycling and export, food chain sup-
port, and fish and wildlife habitat.
NUTRIENT CYCLING
The nutrient-cycling function of BSWs is closely
related to food chain support and nutrient export, as
well as to nutrient uptake, transformation, and im-
mobilization discussed in preceding chapters. Nutri-
ents pass through both grazing and detrital food
chains in the processes of primary and secondary
production and decomposition and thus provide re-
sources to fish and wildlife populations using wet-
lands and adjacent ecosystems (Sather and Smith
1984:21-39). Nutrients may be retained within a
wetland via intrasystem cycling (transformational
processes) or exchanged with surrounding ecosys-
tems (Mitsch and Gosselink 1993:115).
Distribution of Nutrients
Biomass of forest floors (-76 metric tons-ha"')
exceeds that of trees (-51 metric tons-ha'1) in black
spruce stands of interior Alaska (Van Cleve, Oliver
et al. 1983). Element distribution in forested ecosys-
tems generally parallels biomass distribution
(Brinson 1990), but forest-floor masses of N, P, K,
and Mg exceed those of black spruce trees by factors
of -3 to -5 despite relatively small between-strata
differences in biomass distribution (Van Cleve,
Oliver et al. 1983). These findings suggest that nu-
trients (Ca is an exception) concentrate in the forest
floors of BSWs, as has been shown for some bogs
(Figure 11).
Cycling Times and Fates of Nutrients
Black spruce wetlands of interior Alaska cycle
nutrients slowly (Table 24). Nutrient requirements
(N, P, K) for black spruce are -6 to -8 times less
than those for tree strata of other taiga forest commu-
nities, and residence times for these nutrients in the
forest floors of black spruce stands exceed those of
other taiga communities (pooled) by factors of -2 to
-3 (Van Cleve, Oliver et al. 1983). Black spruce re-
tains needles for up to 30 yr, which maximizes pho-
tosynthate produced for a given nutrient investment
(Horn and Oechel 1983). Mosses also tie up nutri-
ents for long periods of time (Oechel and Van Cleve
1986). In contrast, understory shrubs such as Labra-
dor-tea and blueberry rapidly cycle biomass, N, and
P in BSWs, perhaps taking up pulses of nutrients that
slow-growing black spruce cannot quickly assimi-
late (Chapin 1983a). These nutrients subsequently
become available to black spruce through litterfall
and decomposition.
Graminoids occurring in BSWs also cycle nutri-
ents. Adaptations for nutrient uptake and plant
growth in cold, nutrient-poor environments include
higher root surface-to-volume ratios, lower optimum
temperatures for root growth, and greater capacities
for absorption of P than occur in species and
ecotypes from warmer climates (Chapin 1974). In
addition, graminoids maintain large belowground
nutrient stores and quickly replace aboveground
parts lost to fire or grazing (Bryant et al. 1983).
67
-------
Functional Profile of Black Spruce Wetlands in Alaska
~ 2000
Vascular
Plants
Moss/Peat
(0.0 to 0.3
m)
STRATUM
Deep Peat
(0.3 to 1.5
m)
Figure 11. Potassium distribution in a raised bog (Buttleman and Grigal 1985).
Table 24. Contrasting turnover times for nutrient elements in nonpermafrost black spruce stands in
Ontario and largely permafrost stands in Alaska.
Site Type and Location
Nonpermafrost black spruce on
sand - Ontario
Nonpermafrost black spruce on peat
- Ontario
Taiga black spruce - Alaska
Organic Soil Turnover Time
(yr)
N
35
35
61
P
2
4
99
K
3
6
74
Ca
2
37
39
Mg
3
22
73
Source
Gordon (1983)
Gordon (1983)
Van Cleve, Oliver et al. (1983)
Nutrients can be recycled by respiration and
retranslocation, which act rapidly within living tis-
sue, and leaching and litterfall, which act slowly in
nonliving tissue (Lugo, Brinson et al. 1990). Decom-
position of litterfall mineralizes nutrients, which
again become available for uptake by plants. Nitro-
gen mineralization, for example, dominates N cy-
cling within BSWs (Table 25).
Mire environments inhibit microbiological activ-
ity and limit nutrient cycling (Dickinson 1983). Poor
litter quality and low soil temperatures also limit de-
composition in BSWs of interior Alaska (Brunberg
1983, Flanagan and Van Cleve 1983, Salonius 1983,
Flanagan 1986, Van Cleve and Yarie 1986), although
mineralization rates in minerotrophic wetlands
dominated by graminoids should be higher than in
oligotrophic wetlands dominated by mosses. Accu-
mulating peat further removes nutrient elements
from biogeochemical circulation (Nikonov and
Manakov 1980): >50% of the N input to a Minne-
sota bog entered the catotelm despite rapid turnover
of a small pool of N in the acrotelm (Urban and
Eisenreich 1988).
68
-------
Ecologic Functions
Table-25. Nitrogen mineralization and fixation in a Minnesota bog and Alaska black spruce stands
Site Type and
Location
Black spruce bog -
Minnesota
Black spruce stands -
Alaska
N Mineralization
(kg N-ha''-yr"')
43 to 59
11 to 18
N Fixation (kg
N-ha'V')
0.5 to 0.7
0.9 to 1.4
Source
Urban and Eisenreich (1988)
Flanagan and Van Cleve (1983),
Billington and Alexander (1983)
Functional Summary
Black spruce wetlands, like all ecosystems, cycle
nutrients, but the magnitude of this function is low in
comparison to more productive communities. Nutri-
ent cycling in BSWs involves only a small propor-
tion of total nutrient pools because decomposition of
organic matter is limited. Minerotrophic wetlands,
with higher rates of decomposition, likely cycle
more nutrients than do ombrotrophic wetlands but
are unlikely to approach the nutrient-cycling capa-
bilities of upland deciduous forests in interior
Alaska.
Minerotrophy, evidenced by circumneutral pH,
vegetation with an important component of easily
decomposed graminoid plants, and high Ca and Mg
concentrations, may be an indicator of greater than
average nutrient cycling in BSWs.
Functional Sensitivity to Impacts
The nutrient-cycling function of BSWs is sensi-
tive to placement of fill. Wetland areas covered by
barren fill would not cycle nutrients through plant
uptake or remove waterborne nutrients from the
water column through adsorptive processes involv-
ing organic matter. Buried organic material would
become anaerobic, greatly decreasing nutrient min-
eralization.
Nutrient cycling could be established on fill sur-
faces covered by dense vegetation and, if established
as an upland deciduous forest community, could ex-
ceed that of the buried wetland. Creation of a warm
upland forest stand is an unlikely objective for fill
placement; establishment of grass cover is more
likely (e.g., a golf course). Vegetated fill surfaces in
most cases would not fully offset the nutrient-cy-
cling losses caused by fill placement.
Nutrients will cycle in drained BSWs, but rates of
nutrient-cycling likely will differ from those of com-
parable undrained wetlands. Drainage should warm
soils, as occurred in a drained fen (Lieffers and
Roth well 1987), and increase aeration of the organic
layer, mineralization of nutrients, and plant produc-
tion, all of which suggest enhanced nutrient cycling.
On the other hand, drained minerotrophic BSWs
may become ombrotrophic, which would favor
mosses and woody vegetation resistant to decompo-
sition, as shown for fen strings (Moore 1989). Such
changes suggest decreased nutrient mineralization.
Perhaps the only predictions possible with regard
to nutrient cycling and drainage of BSWs are that in-
creased decomposition coupled with increased net
primary production indicate increased nutrient cy-
cling whereas decreased decomposition coupled
with decreased net primary production indicate de-
creased nutrient cycling. Situations where drainage
changes decomposition and net primary production
in opposite directions are equivocal. Manipulating
the balance of decomposition and production in
drained wetlands to simulate predrainage states
might mitigate impacts on nutrient cycling.
NUTRIENT EXPORT
Wetlands can export nutrients to adjacent or
downstream ecosystems (Adamus and Stockwell
1983:29), a form of food chain support often associ-
ated with coastal wetlands (Sather and Smith
1984:25). In some cases, exported nutrients add to
the productivity of recipient ecosystems, such as
estuaries, which may harbor species of particular
biological and economic significance, such as com-
mercial fishes (de la Cruz 1979, Adamus and
Stockwell 1983:29-37, Mitsch and Gosselink
1984:120-121, Sather and Smith 1984:25-27). Black
spruce wetlands are low-energy environments with
only modest potentials for exporting waterborne
nutrients. The following section discusses N, P, and
C export in Alaska's BSWs.
69
-------
Functional Profile of Black Spruce Wetlands in Alaska
Nitrogen
Nitrogen export from wetlands is a function of
runoff discharge and N concentration. Black spruce
wetlands accumulate organic matter and are nutrient
sinks in which mineralization and immobilization
dominate N cycling. Rapid accumulation of organic
matter reduces the residence time of peat in the
acrotelm where mineralization can occur (Damman
1987) and therefore may reduce N concentration in
peat water (Table 26). Nitrogen export from peat-
forming wetlands to aquatic systems should be small
in relation to the pool of N in organic matter, particu-
larly in northern taiga where runoff and mineraliza-
tion rates are low.
A Minnesota bog receiving 0.80 m of
precipitation-yr1 exported 50% of N input, yielding
6.374 kg N-ha^-yr1 in streamflow, mainly as organic
N (5.388 kg-ha-'-yr1) (Verry and Timmons 1982).
Export of inorganic N from the bog is comparable to
that from natural and agricultural soils of low pro-
ductivity (Wetzel 1983:283). Although N-export
rates are not available for BSWs of interior Alaska,
these sites receive only 0.25 m to 0.50 m of precipi-
tation (Watson 1959 in Wahrhaftig 1965), which
should reduce N export in comparison to sites in
wetter regions. Fens export more N than do bogs in
Minnesota (Clausen and Brooks 1983£>) suggesting
that minerotrophic BSWs may export more N than
ombrotrophic BSWs.
Phosphorus
Phosphorus export from wetlands, like that of N,
is a function of runoff discharge and element con-
centration. Phosphorus occurs in higher concentra-
tions in stagnant peat than in rapidly accumulating
peat (Damman 1987), and runoff concentrations
from peatlands are small (Table 27). Black spruce
wetlands accumulate organic matter and are sinks for
P, which implies that exports should be small in re-
lation to P inputs and stored P.
Minerotrophic BSWs potentially export more P
than do ombrotrophic wetlands because fens gener-
ally have greater flows. An 18-ha Ontario marsh, in
some respects similar to a fen, that received surface
flow from groundwater discharge and from a devel-
oped 130-ha watershed (Gehrels and Mulamoottil
Table 26. Nitrogen export in runoff from bogs and tundra peatland.
Site Type and Location
Undisturbed bogs - Minnesota
Undisturbed bogs - Quebec
Tundra beaded stream - Alaska
Nitrogen Concentration in Runoff
(mg-L'1)
NH4-N
0.1
0.07
0.013
N03-N
0.06
NA1
0.006
Organic N
1.4
NA
NA
Source
Clausen and Brooks (1983a)
Moore (1987)
Oswoodetal. (1989)
1. NA = not available.
Table 27. Phosphorus concentrations in runoff from northern peatlands.
Site Type and Location
Undisturbed bogs - Quebec
Peatland lakes - Labrador
Tundra stream - Alaska
Bogs - Minnesota
Fens - Minnesota
Phosphorus Concentration in
Runoff (lig-L'1)
TOP
28
NA
NA
NA
NA
TP
NA1
19
NA
60
80
PO4-P
NA
NA
13
NA
NA
Source
Moore (1987)
Engstrom(1984)
Oswoodetal. (1989)
Clausen and Brooks (1983b)
Clausen and Brooks (1983b)
1. NA = not available
70
-------
Ecologic Functions
1990) exported P in surface water and groundwater
(Figure 12). The marsh, a strong sink for TP and a
weak source of PO4-P, exported -1.9 kg TP-ha''-yr '
in surface water (Gehrels and Mulamoottil 1990). In
contrast, a Minnesota bog exported only 0.460 kg
TP-ha-'-yr1 (0.308 kg organic P-ha-'-yr1 and 0.154 kg
PO4-P-ha-'-yr') in streamflow and retained 61% of P
input (Verry and Timmons 1982). The rate of P ex-
port from the Minnesota bog is roughly comparable
to that from natural and agricultural soils of medium
productivity (Wetzel 1983:283).
Particulate and Dissolved Organic Carbon
Wetlands export organic C in particulate and dis-
solved forms (Crow and Macdonald 1979; Lugo,
Brown et al. 1990). For example, the DOC content
of several streams flowing through temperate
marshes doubled (Wetzel and Otsuki 1974 in Wetzel
1983). Dissolved organic C is a constituent of dis-
solved organic matter (DOM), which is made up of
dissolved nonhumic and dissolved and colloidal hu-
mic substances; DOC is the predominant form of
organic C in freshwater systems, often occurring at
6 to 10 times the concentration of POC (Wetzel
1983:667,676). Wetlands may have slightly lower
ratios of DOC to POC, on the order of 3 to 6 (Lugo,
Brown et al. 1990), than typical of lakes and streams.
Humic and fulvic acids (Figure 13); chemical
oxygen demand (COD), e.g., 389 kg COD-ha-'-yr1
for a Minnesota bog (Verry and Timmons 1982); and
DOC and TOC concentrations (Table 28) in peatland
runoff demonstrate C export, as do measures of and
unit-area C yields on the same order as those for
southern freshwater swamps (Table 29). A
clearwater lake surrounded by mineral soils showed
only 7.18 mg DOC-L'1 (Bourbonniere 1989), but
typical values for peatland runoff are ~3 to ~6 times
higher (Table 28). Moore (1988) characterized C-
export rates from Quebec mires (Table 29) as rela-
tively high.
Peat carbon supports aquatic food webs in the
Arctic (Schell 1983), suggesting a similar function
of organic C in taiga aquatic systems. The mire-
draining Bigoray River of Alberta supported 112
species of chironomids in a reach of only 150 m, a
species richness attributed to an abundance of micro-
[• Organic Phosphorus1
|HOrthophosphate
Surface Ground
Water Water
DISCHARGE COMPONENT
Figure 12. Phosphorus exports from an organic-substrate cattail marsh, Ontario
(Gerhrels and Mulamoottil 1990).
71
-------
Functional Profile of Black Spruce Wetlands in Alaska
BHumic Acids
• Fulvic Acid
Bogs
Fens
MIRE TYPE
Figure 13. Humic andfulvic acid concentrations in runoff from Minnesota mires (Clausen and Brooks 1983b).
Table 28. Carbon concentrations in runoff from northern peatlands.
Site Type and Location
Subarctic mires
Headwater lakes in peatland
watersheds - Finland
Bogs (upper pore water) - Nova
Scotia and Quebec
Bogs (upper pore water) - Nova
Scotia and Quebec
Bogs (natural streams) - Nova
Scotia and Quebec
Bogs (drainage ditches) - Nova
Scotia and Quebec
Undisturbed bogs - Quebec
Mires - Quebec
Tundra beaded stream - Alaska
Colville River (spring flows) -
Alaska
Carbon Concentration in Mire
Runoff (mg-L ')
DOC
19.3
NA
38.5
47.1
34.5
29.0
33.7
19.3
NA
NA
TOC
NA1
10.9 (mean),
33.9 (max)
NA
NA
NA
NA
NA
NA
-10
19.3
Source
Moore (1988)
Kortelainen and Mannio (1988)
Bourbonniere (1987, 1989)
Bourbonniere (1987, 1989)
Bourbonniere (1987, 1989)
Bourbonniere (1987, 1989)
Moore (1987)
Moore (1988)
Oswoodetal. (1989)
Schell and Ziemann (1983)
1. NA = not available.
72
-------
Ecologic Functions
Table 29. Carbon export rates for swamps and peatlands.
Site Type and Location
Freshwater swamps - southern USA
Tundra and taiga regions
Boreal fens - Quebec
Boreal bog - Quebec
Undisturbed subarctic mires
Unit-Area Carbon
Export (kg C-ha '-yr ')
TOC
20 to 100
23
NA
NA
NA
DOC
NA1
NA
13 to 33
48
10 to 50
Source
Mitsch and Gosselink (1986:120-121)
Lugo, Brown et al. (1990).
Moore (1988)
Moore (1988)
Moore (1987fc in Moore 1989)
1. NA = not available.
habitats, including organic matter in bottom sedi-
ments (Boerger 1981). LaPerriere (1983) found a
significant positive relationship between concentra-
tion (number-volume"1) of invertebrate drift and al-
kalinity in 13 interior Alaska streams but no
significant relationship between alkalinity and chlo-
rophyll a. She hypothesized that these findings could
be explained if anions of organic acids provided
noncarbonate alkalinity, DOC flocculated to form
POC, and heterotrophic degradation of POC sup-
ported an invertebrate community, although P. H.
Glaser (Univ. Minn., pers. commun.) questions an-
ions of organic acids as sources of noncarbonate al-
kalinity.
Ecologic studies relating fish use to organic C in
brownwater taiga systems are virtually absent, but
brownwater streams draining BSWs of interior
Alaska sometimes support high fish densities, per-
haps related to wetland C export acting through food
chains or elevated water temperatures. Arctic gray-
ling (Thymallus arcticus) spawn and rear at high
density in brownwater systems (e.g., Shaw Creek,
Tanana River drainage), although clearwater systems
provide overwintering and adult feeding habitat;
longnose sucker (Catostomus catostomus), lake
chub (Coueslus plumbeus), northern pike (Esox
lucius), and (at least occasionally) rearing coho
salmon (Oncorhynchus kisutch) also occur at high
densities in brownwater systems (W. P. Ridder,
Alaska Dep. Fish Game, pers. commun.).
Brownwater systems draining to the Tanana River of
interior Alaska appear to support high densities of
longnose sucker (A. G. Ott, Alaska Dep. Fish Game,
pers. commun.).
Functional Summary
Black spruce wetlands with outflows perform the
nutrient-export function, but the magnitude of such
export is small. Nitrogen and P exports from BSWs
to streams and lakes probably are insufficient to al-
ter their generally oligotrophic status, but exported C
may support detrital food chains in taiga brownwater
streams. Minerotrophic BSWs may export more N
and P than do ombrotrophic wetlands. Conversely,
ombrotrophic BSWs may export more C than do
minerotrophic wetlands, based on data from bogs
and fens.
Discharge of water from a BSW indicates some
nutrient export. Water stained by DOM specifically
indicates C export. Wetland surfaces showing high
degrees of decomposition and little accumulation of
organic matter (i.e., stagnant peat growth) may indi-
cate greater nutrient export than wetland surfaces
showing rapid peat accumulation. In the unlikely
event that a BSW exported substantial quantities of
N and P, downstream eutrophication clearly associ-
ated with wetland discharge might be an indicator of
such export.
Functional Sensitivity to Impacts
The nutrient-export function of BSWs is sensi-
tive to placement of fill, although the effects are am-
biguous for N and P. Fill would bury sources (e.g.,
peat, decomposing litter) of C and reduce or elimi-
nate mineralization of N and P in BSWs, but
minerotrophic wetlands might continue to export
some nutrients by groundwater flow through buried
peat. Fill surfaces composed of topsoil or organic
matter with high nutrient contents might export more
73
-------
Functional Profile of Black Spruce Wetlands in Alaska
N and P than an undisturbed BSW. Similarly, uses of
fill surfaces that included application of fertilizers or
other anthropogenic sources of N and P potentially
would increase nutrient export. Flows emanating
from fill surfaces and the concentrations of nutrients
in those flows might be adjusted to match natural
conditions to mitigate impacts of fill on the nutrient-
export function of BSWs. Such adjustments are un-
likely to be compatible with the purposes for which
fills are placed, however.
Drainage of BSWs can, at least temporarily, in-
crease nutrient exports through enhanced aerobic de-
composition of peat, although the magnitude of
increased nutrient export may be small. Mineralized
nutrients and TOC should readily move through
drainage ditches to receiving waters. Ditching tem-
porarily increased DOC in bog runoff to 55 mg
C-L'1 before dropping back to 35 to 43 mg C-L"1 at a
Quebec site (Moore 1987), and peat mining signifi-
cantly increased levels of NH4-N and organic N in
bog runoff (Clausen and Brooks 1983a). Mitigating
the effects of drainage on the nutrient-export func-
tion of BSWs appears unlikely.
FOOD CHAIN SUPPORT
Food chain support includes, or is closely related
to, primary production and the previously discussed
functions of nutrient cycling and nutrient export.
Photosynthesis supports secondary production, ei-
ther directly through the grazing pathway or indi-
rectly through the detrital pathway (Crow and
Macdonald 1979, Sather and Smith 1984:21-39).
Highly productive (eutrophic) wetlands provide
more support to food chains than do upland ecosys-
tems or nutrient-poor (oligotrophic) wetlands
(Richardson 1979, Adamus and Stockwell 1983:31,
Mitsch and Gosselink 1986:121-123).
Primary Production
Photosynthesis produces carbohydrates (gross
primary production) that, if unrespired, accumulate
as plant biomass (net primary production), which
supports food chains. State factors topography,
time, climate, biota, and soil parent material - condi-
tion ecosystem controls to limit net primary produc-
tion (Van Cleve et al. 1991). Cold, wet taiga sites,
such as BSWs, are less productive than warm sites
(Van Cleve and Yarie 1986), and fens are more pro-
ductive than bogs (Boelter and Verry 1977), al-
though biomass may be similar in each (Swanson
and Grigal 1991). Vegetation and nutrient availabil-
ity even may vary within bogs because
drainageways and peripheral portions receive greater
masses of nutrients than do internal portions
(Damman 1987; Zoltai, Tarnocai et al. 1988).
Low temperatures limit photosynthesis and
growth in trees. For taiga hardwoods, total root res-
piration increases with increasing soil temperature;
significant growth respiration of roots occurs at 5°C
for American green alder, at 15°C and 25°C for bal-
sam poplar, and at all three temperatures for quaking
aspen (Lawrence and Oechel 1983
-------
Ecologic Functions
30
HSoil Temperature |
• Air Temperature j
UJ
Balsam Quaking American
Poplar Aspen Green
Alder
SPECIES
Paper
Birch
Figure 14. Soil and air temperatures at which maximum photosynthetic rates occurred in seedlings of taiga hard-
woods (Lawrence and Oechel 1983b).
Balsam Quaking Paper Black
Poplar Aspen Birch Spruce
SPECIES
Figure 15. Annual production of taiga trees near Fairbanks, Alaska (Viereck et al. 1983).
75
-------
Functional Profile of Black Spruce Wetlands in Alaska
after desiccation to 62% moisture (Skre and Oechel
1981). Nevertheless, leaf water content in several
moss species can fall from near optimum to below
the photosynthetic compensation point in periods as
short as 3 days and frequently can be below this
point in July (Skre et al. 1983i>). Among hummock
and hollow mosses occurring together, Sphagnum
angustifolium (a hollow species) had significantly
greater growth rates under high moisture conditions
than did S. magellanicum and 5. fuscum (hummock
species), although the situation reversed during a dry
year, when all three species showed less growth
(Luken 1985). Low light intensities and lack of
moisture also limit photosynthetic rates in
Polytrichum commune and the feathermosses
Hylocomium splendens and Pleurozium schreberi
(Horn 1986).
Community primary production in Alaska's
BSWs may reach or exceed 2,000 kg-ha''-yr', based
on combined aboveground production by black
spruce, shrubs, and mosses and belowground pro-
duction found in similar wetlands. This value is near
the lower end of the range of productivities for
northern hemisphere mires and far below the
productivities of riverine forests (Table 30).
Food Chains
The net primary production of BSWs enters two
trophic pathways: grazing (includes browsing) and
detrital. Herbivores direct energy contained in living
plant tissues to the grazing pathway. Plant species
have evolved mechanisms, such as production of
antiherbivory compounds, to reduce the impact of
grazing on their ability to grow and reproduce.
Nutrient-poor sites such as bogs support stress-
adapted, slow-growing, evergreen woody plants
(e.g., black spruce and Labrador-tea) known to be
unpalatable to vertebrate herbivores and often con-
taining antimicrobial resins that interfere with cecal
and rumen digestive functions (Bryant and Kuropat
1980, Bryant 1984:22). Browsing on more palatable
early successional species may even favor eventual
dominance by less palatable slow-growing ever-
green vegetation (Bryant and Chapin 1986). Plants
occurring in mature ombrotrophic BSWs thus con-
tain antiherbivory compounds, which should reduce
the proportion of community production entering the
grazing pathway. The palatability of fast-growing
deciduous vegetation in high-nutrient environments
(Bryant and Chapin 1986) should act to enhance the
relative difference in potential food chain support
between BSWs and well-drained uplands.
Nutrient-poor wetlands generally support few
herbivorous species, particularly large vertebrates
(Mason and Standen 1983, Speight and Blackith
1983). Nevertheless, moose (Alces alces), barren-
ground caribou (Rangifer tarandus granti), snow-
shoe hare (Lepus americanus), spruce grouse
(Dendragapus canadensis), fruit- and seed-eating
songbirds, and rodents potentially feed in BSWs.
Table 30. Comparative production of selected wetland communities and community components.
Site Type and Location
Patterned fen - Quebec
Patterned fen - Quebec
Muskeg - Manitoba
Bog forest - Manitoba
Shrub fen - Michigan
Mires - northern
hemisphere
Riverine forests
Community
Component
Flark pools
Strings
Trees
Trees
Entire
community
Entire
community
Entire
community
Production
(kg-ha-V1)
70
930
720
3,030
3,400
3,000 to
10,000
6,850 to
21,360
Source
Moore (1989)
Moore (1989)
Reader and Stewart (1972 in Brown 1990)
Reader and Stewart (1972 in Brown 1990)
Richardson (1979)
Bradbury and Grace (1983)
Brinson(1990)
76
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Ecologic Functions
With the exception of spruce grouse and snowshoe
hare, which sometimes feed on black spruce, boreal
vertebrate herbivores neither consume appreciable
quantities of black spruce (Ellison 1976, Wolff
1978a, Bryant and Kuropat 1980) nor consume
mosses, the two major producers of biomass in
ombrotrophic BSWs. Vertebrate herbivores do con-
sume shrubs, herbs, lichens, fruits, and seeds (in-
cluding those of black spruce) occurring in BSWs,
however (e.g. Skoog 1968:137-147, Coady 1982,
Gasawayetal. 1983:23-24).
Invertebrate herbivores occupying BSWs also di-
rect primary production to the grazing food chain.
Black spruce stands of interior Alaska support many
taxa of herbivorous arthropods (Figure 16). The
trophic structure of their arthropod faunas should
broadly resemble those of BSWs.
Fens often support greater numbers of vertebrates
(in particular, herbivores) than do bogs (Speight and
Blackith 1983), perhaps because fens have more
nutrients and often support graminoid vegetation.
Graminoids, although sometimes containing
antiherbivory compounds in low-nutrient environ-
ments, have adapted to disturbance by maintaining
belowground reserves of C and producing nutritious
shoots in response to grazing (Bryant et al. 1983).
Barren-ground caribou, moose, rodents, and birds
(e.g., waterfowl) consume vegetation characteristic
of fens (e.g., Coady 1982, White et al. 1975, Lacki
et al. 1*990). Thus, herbivores may consume a greater
proportion of available biomass in minerotrophic
than in ombrotrophic BSWs.
The detrital pathway accounts for most energy
flow in ecosystems (Krebs 1972:497), and respira-
tion by decomposer organisms greatly exceeds that
by herbivores in bogs (Mitsch and Gosselink
1993:404-407). Tundra peatland communities,
known to share many similarities with those of the
taiga (Kummerow et al. 1983), support few herbivo-
rous taxa (Batzli et al. 1980) and directly contribute
-80% of their primary production to the detrital
pathway in the form of dead (unconsumed) vegeta-
tion (MacLean 1980)., Black spruce wetlands may
contribute a similar proportion of their primary pro-
duction to the detrital pathway, but relative verte-
brate biomasses supported by grazing and detrital
Herbivores Saprovores Herbivores +
Saprovores
TROPHIC LEVEL
Predators
Figure 16. Distribution of above ground arthropod taxa among trophic levels in black spruce stands of
interior Alaska (Werner 1983).
77
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Functional Profile of Black Spruce Wetlands in Alaska
pathways in BSWs apparently have not been docu-
mented. The detritus-based food chain may be im-
portant to taiga birds, however (P. D. Martin, U.S.
Fish Wildl. Serv., pers. commun.).
Organic layer respiration by microbes, inverte-
brate microbivores (organisms feeding on algae,
bacteria, or fungi [MacLean 1980]), and invertebrate
saprovores (organisms directly consuming decaying
organic matter) indicates energy flow in the detrital
pathway. In tundra systems, microbivores account
for a greater proportion of soil faunal biomass than
do saprovores, but the reverse is true in many forest
ecosystems (MacLean 1980). Over two seasons, the
organic layer of a black spruce stand (probably
nonwetland) respired 1,345 and 1,358 g CO2-nr2,
generally slightly less than those of comparable as-
pen, birch, and white spruce stands (Schlentner and
Van Cleve 1985).
The degree of similarity between the soil inver-
tebrate faunas of European blanket bogs and Alaskan
tundra (Table 31) suggest a similar fauna for BSWs.
Some soil invertebrates of BSWs, as well as arthro-
pod saprovores and predators in aboveground veg-
etation (Figure 16), should be vulnerable to
vertebrate predation and thus support higher trophic
levels of detrital food chains. At least ten species of
insectivorous and partially insectivorous birds
(Gabrielson and Lincoln 1959) are present in BSWs,
as are small mammals (e.g., shrews) that feed on in-
vertebrates.
The margins of taiga ponds occurring within
BSWs may provide warm littoral microenviron-
ments conducive to decomposition and support of
detrital food chains, including a wide variety of in-
sectivorous birds (P. D. Martin, U.S. Fish Wildl.
Serv., pers. commun.), but energy flows in these
environments apparently have received little or no
study. Annual rates of primary and secondary pro-
duction in BSWs may be less important to birds than
are brief pulses of production occurring during the
nesting season (P. D. Martin, U.S. Fish Wildl. Serv.,
pers. commun.). Although more energy flows to in-
vertebrate carnivores than to vertebrate carnivores
(primarily insectivorous birds) in Alaskan tundra
systems (MacLean 1980), relative energy flows in
BSWs are unknown.
Functional Summary
Black spruce wetlands support grazing and detri-
tal food chains, which merge at higher trophic levels.
Ombrotrophic to weakly minerotrophic BSWs have
low net primary production (i.e., potential energy
available to consumers) and unpalatable plants resis-
tant to decomposition, which should reduce energy
flow in grazing and detrital pathways. In contrast,
moderately to strongly minerotrophic BSWs have
elevated base element concentrations and moderate
pH values that favor enhanced net primary produc-
tion by graminoid vegetation adapted to grazing.
Such vegetation potentially decomposes more
quickly than ericaceous vegetation of ombrotrophic
wetlands and probably increases energy flow in
grazing and detrital pathways. Although the food-
chain support function of BSWs, measured by com-
munity production, is lower than that of well-drained
taiga uplands, it is essential to organisms limited to
wetland environments. In addition, BSWs cover im-
mense areas of interior Alaska and, in aggregate,
substantially contribute to energy flow in taiga land-
scapes.
Minerotrophy may indicate the magnitude of the
food chain-support function of BSWs and can be
determined by analysis of hydrology, water chemis-
try (conductivity, alkalinity, pH), or vegetation
Table 31. Common soil invertebrates found in European blanket bogs and Alaska tundra.
Site Type
and Location
Blanket bogs
- United
Kingdom
Tundra -
Alaska
Oligochaeta
(Enchytraeidae)
Yes
Yes
Diptera
(Tipulidae)
Yes
Yes
Acari
Yes
Yes
Nematoda
Yes
Yes
Collembola
Yes
Yes
Source
Mason and
Standen
(1983)
MacLean
(1980)
78
-------
Ecologic Functions
(Swanson and Grigal 1989). Observation of animal
use (e.g., browsed shrubs, fecal pellets, tracks, bird
calls, visual sitings) or the presence of preferred food
items for herbivores also indicate food chain sup-
port. In those few cases where rates of net primary
production are known, higher production indicates
greater food chain-support function, all other factors
being equal.
Functional Sensitivity to Impacts
The food chain-support function of BSWs is sen-
sitive to placement of fill, which eliminates primary
production and thus the grazing pathway of energy
flow. Buried organic matter generally will not pro-
vide energy to the detrital pathway even if anaerobic
fermentation continues beneath fill surfaces. Barren
fill eliminates energy flow to higher trophic levels.
Re-establishment of vegetative cover, particu-
larly that emulating the undisturbed wetland, could
mitigate the effects of fill placement on food chains
but is unlikely to be compatible with fill purposes.
For "out-of-kind" revegetation, plant species should
be chosen for palatability to nonwetland herbivores.
Addition of organic material to fill surfaces would
provide a source of nutrients via mineralization and
might enhance establishment of detrital food chains.
The food chain-support function of BSWs is
much less sensitive to drainage than to fill place-
ment. Drainage may increase net primary produc-
tion, particularly that of trees. Drained minerotrophic
wetlands can become ombrotrophic, community
production decline, and species composition change
to favor unpalatable evergreen trees and shrubs, po-
tentially reducing energy flow in the grazing path-
way. Increased decomposition in drained BSWs
would increase energy flow through the detrital path-
way, perhaps offsetting declines in the grazing path-
way. Despite these somewhat unpredictable changes,
the basic processes of primary production, herbivory,
decomposition, and predation can proceed in a
drained wetland.
Habitat manipulation might be used to mitigate
shifts in dominance by plant species and potential
losses in productivity in drained BSWs. Controlled
burning, for example, could prevent shifts from
graminoids to woody vegetation. Nutrient release by
fire potentially would increase net primary produc-
tion in drained forested wetlands, possibly enhanc-
ing food chain support.
HABITAT
Wetlands provide habitat for plants and animals,
including fish and wildlife species of socioeconomic
and ecologic significance (Weller 1979, Adamus and
Stockwell 1983:38-45, Sather and Smith 1984:40,
Mitsch and Gosselink 1986:393-399). Although of-
ten associated with waterfowl and furbearers such as
beaver and muskrat (Mitsch and Gosselink
1986:394-395), wetlands also support other biologi-
cally-important species such as nongame birds
(Kroodsma 1979), invertebrates and cold-blooded
vertebrates (Sather and Smith 1984:43-44), threat-
ened and endangered species (Mitsch and Gosselink
1986:398), and terrestrial mammals such as moose
that use wetlands on a seasonal basis (Weller 1979).
Birds
Avian habitats do not necessarily coincide with
subdivisions of the environment (e.g., BSWs, spe-
cific plant communities) defined by humans. Water-
fowl, for example, use temporarily flooded
palustrine wetlands when ponds and lakes are still
frozen in early spring (P. D. Martin, U.S. Fish Wildl.
Serv., pers. commun.) but may shift preferences dur-
ing nesting, brood rearing, and foraging. Defining
the boundaries of BSWs with respect to avian habi-
tats is difficult and somewhat arbitrary, particularly
when considering included or adjacent waterbodies
(e.g., patterned fens, bog or fen lakes, thermokarst
ponds) whose hydrology, chemistry, and productiv-
ity may be influenced by such wetlands.
This profile discusses habitat use by waterbirds
and shorebirds that occupy included or adjacent
waterbodies as well as habitat use by birds directly
occupying black spruce communities. Appendix D
interprets community descriptions in avian surveys
with respect to BSWs or habitats sharing common
characteristics with BSWs. Taxonomic binomials for
avian species appear in Tables 32 through 35.
Waterbird use of mires, or waterbodies having
characteristics indicative of mires (e.g., floating peat
mats, common mire plants), provides evidence for
potential association with BSWs (Table 32). Species
recorded as breeding on, or adjacent to, taiga mire
waterbodies in Alaska include Pacific loon, tundra
and trumpeter swans, green-winged teal, mallard,
northern pintail, northern shoveler, American
wigeon, greater and lesser scaup, white-winged sco-
ter, mew and Bonaparte's gulls, and arctic tern. Al-
79
-------
Functional Profile of Black Spruce Wetlands in Alaska
though not recorded as breeders, common loon,
horned and red-necked grebes, lesser Canada goose,
ring-necked duck, common and Barrow's gold-
eneyes, bufflehead, and glaucous-winged and her-
ring gulls also occurred on mire waterbodies and are
moderately probable to be associated with BSWs.
Other waterbirds using taiga ponds, lakes, and
marshes (Table 32) may or may not be associated
with BSWs.
Birds of prey directly use BSWs for hunting and
sometimes nesting (Table 33). Black spruce wet-
lands present a range of structural and trophic char-
acteristics that offer potential habitat to most avian
predators occupying taiga landscapes. The northern
harrier, northern hawk owl, great gray owl, short-
eared owl, and boreal owl have a high probability of
nesting in BSWs. The American peregrine falcon
and great horned owl nest elsewhere but are highly
likely to hunt in (or above) BSWs. These wetlands
are moderately probable hunting habitat for the bald
eagle, sharp-shinned hawk, northern goshawk, red-
tailed hawk, rough-legged hawk, American kestrel,
and merlin.
Among nonpasserine birds of Alaska taiga other
than waterbirds and raptors (Table 34), the spruce
grouse, sandhill crane, greater and lesser yellowlegs,
solitary sandpiper, Hudsonian godwit, least sand-
piper, short-billed dowitcher, common snipe, red-
necked phalarope, three-toed woodpecker,
black-backed woodpecker, and northern flicker have
a high probability of nesting in BSWs. Sharp-tailed
grouse and upland sandpipers have a moderate prob-
ability of nesting in BSWs. Willow ptarmigan and
ruffed grouse are moderately likely to forage in such
wetlands but do not nest in them.
A significant number of Alaska's taiga passerines
(Table 35) have a high probability of nesting in
BSWs: olive-sided flycatcher; western wood-pee-
wee; alder flycatcher; tree swallow; gray jay; boreal
chickadee; ruby-crowned kinglet; gray-cheeked and
Swainson's thrushes; American robin; varied thrush;
Bohemian waxwing; orange-crowned, yellow-
rumped, and blackpoll warblers; American tree,
chipping, savannah, fox, song, Lincoln's, and white-
crowned sparrows; dark-eyed junco; rusty blackbird;
pine grosbeak; white-winged crossbill; and common
redpoll. Violet-green and bank swallows and the
common raven nest elsewhere but are highly likely
to forage in BSWs. Species with a moderate prob-
ability of nesting in BSWs are northern shrike,
Wilson's warbler, and golden-crowned sparrow.
Cliff swallows and black-capped chickadees are
moderately likely to forage in these wetlands.
..Although many avian species use BSWs, or some
subset thereof, the magnitude of such use is a func-
tion of species distribution and abundance and
strength of species association with such wetlands.
The probabilities presented in Tables 32 through 35
show that BSWs provide habitat for a substantial
number of avian species. These probabilities do not
take bird abundance and distribution into account
and thus do not necessarily reflect the constellation
of birds likely to be encountered in the average
BSW. For example, the Hudsonian godwit is
strongly associated with BSWs (P.D. Martin, U.S.
Fish Wildl. Serv., pers. commun.) but is rare in
Alaska taiga; therefore a given BSW has a low prob-
ability of use by godwits.
Several investigators have structured their avian
surveys to identify birds commonly found in habitats
that can be interpreted with respect to BSWs. Table
36 lists birds regularly found in, and dependent
upon, BSWs. Species occurring at low densities,
such as widely spaced predators, or species associ-
ated with a wide variety of plant communities appear
in Tables 32 through 35 but may not appear in Table
36.
Dark-eyed juncos frequently are the most abun-
dant breeders in BSWs of interior Alaska (Spindler
1976, Spindler and Kessel 1980). White-crowned
sparrow, common snipe, yellow-rumped warbler,
lesser yellowlegs, ruby-crowned kinglet, gray-
cheeked thrush, American robin, Swainson's thrush,
gray jay, Bohemian waxwing, and savannah sparrow
are among the consistently occurring species in these
wetlands (Table 36).
Mammals
Black spruce forest and woodland covers much
of interior and southern Alaska below treeline. Spe-
cies of mammals occupying black spruce forest,
post-fire seres sharing structural characteristics with
shrubby wetlands, and some palustrine emergent
wetlands potentially occur in BSWs as well. Taxo-
nomic binomials for common names of mammals
appear in Tables 37 through 39.
Small insectivorous and herbivorous mammals
are among the most characteristic mammals of
80
-------
Ecologic Functions
BSWs (Table 37). The common, pygmy, dusky, and
northern water shrews; red squirrel; meadow jump-
ing mouse; northern red-backed, tundra, meadow,
and yellow-cheeked voles; northern bog lemming;
porcupine; and snowshoe hare all are highly prob-
able to breed and forage in BSWs. Species with a
moderate probability of breeding and foraging in
BSWs are beaver, brown lemming, and muskrat. In
the case of beaver and muskrat, however, the asso-
ciation may be largely coincidental (D.K. Swanson,
Nat. Resour. Conserv. Serv., pers. commun.). Little
brown bats are moderately likely to forage over
BSWs.
Carnivores (Table 38) feed on the insectivores
and small herbivorous mammals occurring in these
wetlands. Lynx, wolverine, marten, ermine, least
weasel, mink, and black bear are highly probable to
breed and forage in BSWs, and coyote, wolf, red
fox, and brown bear are highly probable to forage in
such wetlands but may den elsewhere. Other carni-
vores are unlikely to use BSWs.
Of Alaska's two large indigenous taiga herbi-
vores (Table 39), the moose is highly likely to breed
and forage in some types of BSWs and the caribou
is highly likely to use BSWs as winter range. Char-
acteristic black spruce communities of interior
Alaska (Foote 1983) contain little moose browse;
thus, unbroken expanses of mature black spruce for-
est, including treed wetlands, provide poor habitat
for moose. The moose habitat function of BSWs de-
pends, in part, on community composition, structure,
successional state, and diversity, factors poorly de-
fined by "BSW." The value of BSWs as winter range
for caribou largely is a function of the presence of
preferred lichens and herbaceous vegetation, but
black spruce helps maintain low-density snow con-
ditions favorable for caribou feeding.
The probabilities presented in Tables 37 through
39 are those that a species at least occasionally uses
BSWs but are not the probability that a species will
be found in a given BSW. Small mammals and fur-
bearers are the really characteristic species of BSWs.
Table 40 presents those species judged to be consis-
tently present in most BSWs, although the frequency
with which they are encountered varies with their
typical areal density.
Amphibians
The environmental conditions of interior Alaska
are hostile to reptiles and amphibians (e.g., Hodge
1976:17-19). Only a single species, the wood frog
(Rana sylvatica), represents these ectothermic ver-
tebrate classes in the Interior (Kessel 1965, Hodge
1976:54-56). Wood frogs are distributed across bo-
real North America from Alaska, where their range
extends northward to the Brooks Range (Hock 1956
in Hadley 1969:1), to Labrador and south along the
Appalachian Mountains (Conant 1958: 303,352).
The wood frog's life cycle presents three potential
opportunities for using BSW habitats: breeding, for-
aging, and hibernation.
Wood frogs breed and deposit egg masses in
clumps in warm microenvironments within breeding
ponds (Scale 1982). In Alaska, synchronous breed-
ing occurs as soon as air temperature rises above
0°C, surficial soils thaw, and open water develops
(Kessel 1965, Kirton 1974:36, Waldman 1982).
Communal aggregates of egg masses exhibit el-
evated internal temperatures as compared to sur-
rounding water (Herreid and Kinney 1967, Seale
1982, Waldman 1982), which causes central
(warmer) egg masses to hatch more successfully
than peripheral masses (Waldman 1982). Warm mi-
croenvironments also increase fertilization rates
(Herreid and Kinney 1967) and, in bogs, increase
hatching success (Kams 1992). The thermal charac-
teristics of highly-colored, solar-heated ponds or
drainages in ombrotrophic wetlands would seem to
favor wood frog reproduction but are offset by low
pH (Table 41). Bogs are suboptimal breeding habi-
tat as compared to poor fens and fens.
Wood frogs occupy moist wooded areas, often
far from water (Conant 1958:303, pers. observ.).
Post-breeding habitat use of terrestrial areas by wood
frogs apparently has not been studied in interior
Alaska, although frogs occurred in a birch-aspen
woodland prior to entering hibernation (Kirton
1974:2-4). For frogs breeding in bogs and fens, at
least transitory use of terrestrial mire habitats must
occur during movements from hibernacula to breed-
ing sites and from breeding sites to terrestrial forag-
ing areas. Similar use of BSWs is likely.
Wood frogs overwinter in leaf litter by supercool-
ing and tolerating extracellular freezing (Storey and
Storey 1984). In interior Alaska, Kirton (1974:3-31)
located frog hibernacula near waterbodies (mean
distance = 8.2 m). Overwinter survival of juvenile
frogs was greater in dry than in damp hibernacula.
81
-------
Table 32. Use of aquatic habitats potentially associated with black spruce wetlands (BSW) by waterbirds (loons, grebes, waterfowl, gulls,
and terns) in Alaska.
Species
Red-Throated Loon
(Gavia stellata)
Pacific Loon (Gavia
pacified)
Common Loon (Gavia
immer)
Pied-Billed Grebe
(Podilymbus
podiceps)
Horned Grebe
(Podiceps auritus)
Red-Necked Grebe
(Podiceps grisegena)
Tundra Swan (Cygnus
columbianus)
Trumpeter Swan
(Cygnus buccinator)
Greater White-Fronted
Goose (Anser
albifrons)
Lesser Canada Goose
(Branta canadensis
parvipes)
Abundance in
Alaska Taiga
(Common,
Uncommon, Rare,
Casual/
Accidental)
U7'15
C7, Uls near upper
Susitna
C7, U15 near upper
Susitna
A7 in southcoastal
only
C7, U15 near upper
Susitna
C7, U15 near upper
Susitna
U7
C15
U7'19
C7
Habitat Use (Breeding or Potentially Breeding = B, Generally Occurring
or Unspecified Use = O) and Preference When Tested (Selected = [+],
Neutral = [0], Avoided = [-])
Mire Lakes and Ponds
B4'5: [0] only use larger
waterbodies5
O6: [+]lowpHand
conductivity
0": [+]bogs
O4'5'9'16: [-] only use
larger waterbodies5
O4
B13: taiga-tundra
ecotone13 with mire
vegetation14
B21: lakes with fen
vegetation19'20'21 in
needleleaf forest18
O4
Freshwater Marsh and
Open Water
B5: [0] herb marsh, [+]
sedge marsh
B17
O6, B17
B5'17
O4'5, B17
Tundra or Taiga
Lakes and Ponds
O1'2, B3'7'8: [+] small
ponds8
O1'2, B7'15
Ql,2,IO g3,5,7,15
,-.11,12 03,5,7,10,15,16
U , B
/-.11.I2 ,3.1,5.7,10,15,16
U , D
O15, B7
O3'10: [+] low Ca lakes3
T, 3,5,7,13,15
O3: [+] low Ca lakes
B3'5'7'19
O3'1"'19: [+] low Ca
lakes3, uses ''muskeg"19
B3'5'7
Probability Species
Uses Aquatic
Habitats Associated
with BSW
(Low = L, Medium =
M, High = H)
L: few data, low
density
H: larger waterbodies
M: few data
L: accidental
occurrence
M: minerotrophic
waterbodies
M: minerotrophic
waterbodies
H: in forest-tundra
H: in major breeding
areas
L
M
I
O
a
s
pj
3
:u
a"
^
-------
Table 32 (Cont'd). Use of aquatic habitats potentially associated with black spruce wetlands (BSW) by waterbirds (loons,
grebes, waterfowl, gulls, and terns) in Alaska.
Species
Green- Winged Teal
(Anas crecca)
Mallard (Anas
platyrhynchos)
Gadwall (Anas
strepera)
Northern Pintail (Anas
acuta)
Blue- Winged Teal
(Anas discors)
Northern Shoveler
(Anas clypeata)
American Wigeon
(Anas americana)
Canvasback (Aythya
valisineria)
Redhead (Aythya
americana)
Ring-Necked Duck
(Aythya collaris)
Greater Scaup (Aythya
marila)
Lesser Scaup (Aythya
affinis)
Abundance in
Alaska Taiga
(Common,
Uncommon, Rare,
Casual/
Accidental)
C7, U15 near upper
Susitna
C7, Uls near upper
Susitna
R7
C7, U15 near upper
Susitna
R7'24
C7, U15 near upper
Susitna
p7,15
U7
R7
U7
C7,,5
,-,7,15
Habitat Use (Breeding or Potentially Breeding = B, Generally Occurring
or Unspecified Use = O) and Preference When Tested (Selected = [+],
Neutral = [0], Avoided = [-])
Mire Lakes and Ponds
B3'4'5'16: [0] thaw ponds
and larger waterbodies5
B3'4'5: [-] only use larger
waterbodies5
B3,4,s,i6. [_]onlyuse
larger waterbodies5
B3'4'5: [-] only use larger
waterbodies5
B3'4'5: [0] thaw ponds, [-]
larger waterbodies5
O5'17: bogs17
O4, B3'5: [-] thaw ponds
and larger waterbodies5
B3'5: [-] thaw ponds and
larger waterbodies
Freshwater Marsh and
Open Water
B5'17: [0] herb and sedge
marshes5
B5'17: [0] herb marsh,
[+] sedge marsh5
B7'17
B5'17: [0] herb and sedge
marshes5
B17
B5'17: [0] herb and sedge
marshes5
B5'17: [+] herb and
sedge marshes5
B5'17: [-] herb marsh, [0]
sedge marsh5
B17
O5, B17
B5'17: [+] herb and
sedge marshes5
B5'17: [+] herb and
sedge marshes5
Tundra or Taiga
Lakes and Ponds
p 3,5,7,10,11,15,16,22,2.1
r> 3,5,7,10,11, 15,22,2.1
Q3,15
r, 3,5,7,1(1,11,15,22,23
g3,5,7
T, 3,5,7,10,11,15,22,23
D
D 3,5,7,10,11, 15,22,23
r>
g3,5,7
B3'5'7
g 3,5,7,10,23
g3,5,7,10?,15,23?
0 3,5,7,107,15,23
D
Probability Species
Uses Aquatic
Habitats Associated
with BSW
(Low = L, Medium =
M, High = H)
H: broad trophic
tolerance
H: minerotrophic
waterbodies
L: low density
H: minerotrophic
waterbodies
L: low density
H: minerotrophic
waterbodies
H: broad trophic
tolerance
L: low density
L: low density
M: low density
H: minerotrophic
waterbodies
H: minerotrophic
waterbodies
'
-------
Table 32 (Cont'd). Use of aquatic habitats potentially associated with black spruce wetlands (BSW) by waterbirds (loons,
grebes, waterfowl, gulls, and terns) in Alaska.
Species
Common Goldeneye
(Bucephala clangula)
Barrow's Goldeneye
(Bucephala islandica)
Bufflehead
(Bucephala albeola)
Oldsquaw (Clangula
hyemalis)
White- Winged Scoter
(Melanitta fused)
Surf Scoter (Melanitta
perspicillata)
Black Scoter
(Melanitta nigra)
Common Merganser
(Mergus merganser)
Red-Breasted
Merganser (Mergus
senator)
Glaucous- Winged
Gull (Lams
glaucescens)
Abundance in
Alaska Taiga
(Common,
Uncommon, Rare,
Casual/
Accidental)
C7, U15 near upper
Susitna
C7, U15 near upper
Susitna
C7
p7,15
C7
C7, U15 near upper
Susitna
A7, C15 near upper
Susitna
R7, U15 near upper
Susitna
R7, U15 near upper
Susitna
R7
Habitat Use (Breeding or Potentially Breeding = B, Generally Occurring
or Unspecified Use = O) and Preference When Tested (Selected = [+],
Neutral = [0], Avoided = [-])
Mire Lakes and Ponds
O5: only use larger
waterbodies5
O5: only use larger
waterbodies5
O4'5: only use larger
waterbodies5
B5: [-] only use larger
waterbodies, [0] by post-
breeders5
O4
Freshwater Marsh and
Open Water
0s, B17
B17
B5'17
B5'17: [-] herb marsh, [0]
sedge marsh5
0s, B17
O5
Tundra or Taiga
Lakes and Ponds
r, 3,5,7,10,15
B3,5,7,,5
B3,5,7
QlO g3,5,7,15
B3,5,7
B3,5,7,15
B7'15
B7
010,,5 B3,7
Probability Species
Uses Aquatic
Habitats Associated
with BSW
(Low = L, Medium =
M, High = H)
M: cavity nester7
M: cavity nester7
M: cavity nester7
L
H: minerotrophic
waterbodies
L: few data
L: few data, limited
distribution
L: few data, not
abundant
L: few data, low
density
M: low density
r
'
3
a
Ga
5-
S
3
&•
S'
to
r
-------
Table 32 (Cont'd). Use of aquatic habitats potentially associated with black spruce wetlands (BSW) by waterbirds (loons,
grebes, waterfowl, gulls, and terns) in Alaska.
Species
Herring Gull (Larus
argentatus)
Mew Gull (Larus
canus)
Bonaparte's Gull
(Larus Philadelphia)
Arctic Tern (Sterna
paradisaed)
Abundance in
Alaska Taiga
(Common,
Uncommon, Rare,
Casual/
Accidental)
U7
p7,15
u7-15
U7, Cls near upper
Susitna
Habitat Use (Breeding or Potentially Breeding = B, Generally Occurring
or Unspecified Use = O) and Preference When Tested (Selected = [+],
Neutral = [0], Avoided = [-])
Mire Lakes and Ponds
O4
B«.IMS
B4
B4
Freshwater Marsh and
Open Water
B6
B7
Tundra or Taiga
Lakes and Ponds
„ 7,10,11, 15,25
£>
,-,27 r>7,10,ll,15
O1", B15
Probability Species
Uses Aquatic
Habitats Associated
with BSW
(Low = L, Medium =
M, High = H)
M: nests on gravel
bars2*
H: ground and tree
(spruce) nester26"28
H: nests in low
conifers7'15"26
H: low density
o
1. Gabrielson and Lincoln (1959)
2. Lanctot and Quang (1992)
3. Heglund (1988)
4. Hogan and Tande (1983)
5. Heglund (1992)
6. Gibbsetal. (1991)
7. Armstrong (1990)
8. Davis (1972 in Johnson and Herter 1989)
9. Gillespie and Kendeigh (1982)
10. Martin etal. (1995)
11. West and DeWolfe (1974)
12. Manuwal(1978)
13. Wilk(1993)
14. Talbotetal. (1986)
15. Kessel etal. (1982)
16. Spindler(1976)
17. Erskine(1977)
18. U.S. Fish Wildl. Serv. (1987)
19. Bellrose(1980)
20. McKelvey etal. (1983)
21. Hansen etal. (1971)
22. Spindler and Kessel (1980)
23. Murphy etal. (1984)
24. Kessel and Springer (1966)
25. Burger and Gochfeld (1988)
26. Murie(1963)
27. White and Haugh (1969)
28. J. Wright, Alaska Dep. Fish Game, pers. commun.
'
C-i
-------
Table 33. Use of black spruce wetlands (BSW) in Alaska by raptorial birds (hawks, eagles, harriers, ospreys, falcons, and owls).
Species
Osprey
(Pandion
haliaetus)
Bald Eagle
(Haliaeetus
leucocephalus)
Northern
Harrier {Circus
cyaneus)
Sharp-Shinned
Hawk
(Accipiter
striatus)
Northern
Goshawk
(Accipiter
gentilis)
Swainson's
Hawk (Buteo
swainsoni)
Abundance
in Alaska
Taiga
(Common,
Uncommon,
Rare,
Casual/
Accidental)
R1: locally
abundant2
Uufi, C* in
southcoastal
U1'16:
abundant
migrant7'23
C1, U16 near
upper
Susitna
U1'16:
numbers
follow prey
density
R1: very
rare (Taylor
Highway)20
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or
Unspecified Use = O) and Preference When Tested (Selected = [+], Neutral = [0], Avoided=[-])
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
O7
F14
Mixed Taiga Landscape
Bu: shorelines (primarily lakes2)
B1'16: large trees, cliffs on rivers and
shorelines
gU,i6,22. nest:s on grouncj jn Open country,
wetlands, meadows, moorland and heath
(Europe), scrub woodland
Bu,ii,i3,i4,i5,i6: nests near Qpen ^^ in
mixed, coniferous, and deciduous forest
O5'6'7, F3'10: woodlands, edges, willow,
alder
B1'8'16: often nest in birch in mixed,
deciduous, and coniferous forest
O17l2°: scattered woodland and dwarf
forest near treeline20
Black
Spruce
B3
B11
O9
Wetlands
Mires
O21: H"bogs"
O18'21: [-]
"bogs"21
O12'21: black
spruce12, [+]
"bogs"21
Ijll, 15,18,22,24.
fens15,
bogs'1'22'24
O12: black
spruce
F3: "bogs"
Other
O16'21: BSW16,
[+] shrub
swamps
B3'22: emergent
O4: forested
wetlands
(Europe)
Prey Occurs
in BSW
(Insects = I,
Fish = F,
Birds = B,
Mamm. = M)
F1
F1: largely
scavenger1
B,M22'25: hunts
near
ground10'22
BjM3,9,io,n
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
L: hunting,
near nests
M: foraging,
near nests
H: hunting,
breeding,
sparsely treed
BSW
M: hunting,
scrub- shrub
BSW
M: hunting
habitat, scrub-
shrub and
forested BSW
L: few data
-------
Table 33 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by raptorial birds (hawks, eagles, harriers, ospreys, falcons, and owls).
Species
Red-Tailed
Hawk (Buteo
jamaicensis)
Rough-Legged
Hawk (Buteo
lagopus)
American
Kestrel (Falco
sparverius)
Merlin (Falco
columbarius)
American
peregrine
falcon (Falco
peregrinus
anatutri)
Great Horned
Owl (Bubo
virginianus)
Northern Hawk
Owl (Sumia
ulula)
Abundance
in Alaska
Taiga
(Common,
Uncommon,
Rare,
Casual/
Accidental)
C1:
relatively
abundant2
UI6near
upper
Susitna
U1:
common
migrant
C1
u1-16
C2in
preferred
nesting
habitat
C1, U16 near
upper
Susitna
C^U^near
upper
Susitna
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or
Unspecified Use = O) and Preference When Tested (Selected = [+], Neutral = [0], Avoided=[-])
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
F33
F35,
O26
Mixed Taiga Landscape
F ' : generalist, dense spruce, open areas
B 1,15,16,17. treg ^^ cliff nester, mixed and
coniferous forest
F17: clearings
B 1,10,17,19. cliff and tree nester> alpjne
tundra and western taiga
0S,26)B,AI0,,5,,7. cavity nester> open
woodlands, edges, burns, openings, and
meadows
O27, Bll2|15'1M7: conifers, scattered
woodland and dwarf forest, edges, bums,
openings
F2'17: lakes, streams, all taiga bird
habitats2
B1A29: cliffs along rivers
O12"*, F33, B1A7'15'32'33: cliffs and old stick
nests, coniferous and deciduous forest,
edges, scrub-shrub, habitat generalist
o5,7,39j BUO,1S,1W2,33,35,37,38. ^ ^^
open mixed or coniferous forest near
marshes or clearings, low scrub
Black
Spruce
F17
O12
Ou.
g 10,33,35
Wetlands
Mires
O18
F17: open
"bogs"
B17: bog
hummocks
(Finland)
B24: bogs
p35,39.
Sphagnum35,
black spruce39
Other
F33: emergent
O27: BSW
Prey Occurs
in BSW
(Insects = I,
Fish = F,
Birds = B,
Mamm. = M)
BM,0.,7,1,
B]M.0,,7,,9
B30"31'54: lesser
yellowlegs,
gray jays are
major summer
prey
B10'35,
M10,34,35,36
I,B,M1W3l3S'39
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
M: hunting
habitat, scrub-
shrub and
forested BSW
M: hunting,
sparsely treed
BSW
M: hunting,
sparsely treed
BSW
M: hunting,
sparsely treed
BSW
H: hunting, all
BSW
H: hunting, all
BSW
H: hunting,
breeding, all
BSW
-------
Table 33 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by raptorial birds (hawks, eagles, harriers, ospreys, falcons, and owls).
do
Oo
Species
Great Gray
Owl (Strix
nebulosa)
Short-Eared
Owl (Asia
flammeus)
Boreal Owl
(Aegolius
funereus)
Abundance
in Alaska
Taiga
(Common,
Uncommon,
Rare,
Casual/
Accidental)
R1
C1, U16 near
upper
Susitna
C1, R16 near
upper
Susitna
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or
Unspecified Use = O) and Preference When Tested (Selected = [+], Neutral = [0], Avoided=[-])
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
O16
Mixed Taiga Landscape
O7'42: poplar, white spruce along
watercourses in wetland landscape
F41: [-] dense shrubs
g 1.15,33. nests on stut,s or jn raven nests,
coniferous and deciduous forest near
"muskeg", bogs, edges
O5'7, B1'1"135: ground nester in open
habitats, wetlands, similar to northern
harrier
O6'7, B1'2'1"3'37: cavity nester, mixed,
coniferous, and deciduous forest near
openings, woodlands, meadows
Black
Spruce
p40,41. ,
]pure
stands41
B1
B2,35
Wetlands
Mires
F41: [+] mixed
grass and moss
ground cover
rj 24,40. . M
hi . DOgS ,
black spruce
and/or
tamarack40
(may include
meadows45)
D 15,18,33,47
D I
shrub15,
"bogs"33'47
B51: bogs
(Norway)
Other
plOJ5,50 g46.
sedge meadow
B2: BSW
Prey Occurs
in BSW
(Insects = I,
Fish = F,
Birds = B,
Mamm. = M)
B.M38'40'42'43'44:
rodent
specialist
,,33,35 46,48,49
,10 D 10,53
l,o
M2,10,52,53
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
H: hunting,
sparsely treed
BSW with
graminoids
H: hunting,
breeding,
sparsely treed
BSW
H: hunting,
breeding, all
BSW
I.Armstrong (1990)
2. J. Wright, Alaska Dep. Fish Game,
pers. commun.
3. Palmer (1988a)
4. Wiegers(1990)
5. West and DeWolfe (1974)
6. Kron (1975)
7. Cooper etal.( 1991)
8. McGowan (1975)
9. Zachel (1985)
10. Gabrielson and Lincoln (1959)
11. Bent (1937)
12. Carbyn (1971)
13. Clarke (1982)
14. Clarke (1984)
15. Erskine (1977)
16. Kesseletal. (1982)
17. Palmer (19886)
18. Hogan and Tande (1983)
19. Mindell and Dotson (1982)
20. D.D. Gibson, Univ. Alaska Mus.:
pers. commun.
21.GibbsetaI. (1991)
22. Watson (1977)
23. C. Mclntyre, Natl. Park Serv.,
pers. commun.
24. Larsen (1982)
25. Hamerstrom (1986)
26. Spindler and Kessel (1980)
27. Gillespie and Kendeigh (1982)
28. Murie (1963)
29. Ambrose etal. (1988)
30. White (1982)
3 I.Ambrose (1982)
32. Clark etal. (1987)
33. Johnsgard (1988)
34. White and Haugh (1969)
35. Bent (1938)
36. Houston (1987)
37. Meehan and Ritchie (1982)
38. Jones (1987)
39. Kertell (1982)
40. Nero (1980)
41. Servos (1987)
42. Osborne(1987)
43. Korpimaki (1986)
44. Duncan (1987)
45. Spreyer(1987)
46. Clark (1975)
47. Roberts and Bowman (1986)
48. Baker and Brooks (1981)
49. Village (1987)
50. Lein and Boxall (1979)
51. Hay ward etal. (1993)
52. Korpimaki (1987)
53. Korpimaki and Norrdahl (1989)
54. Hunter et al. (1988)
'
3
a
(33
B"
£
a
I
-------
Table 34. Use of black spruce wetlands (BSW) in Alaska by nonpasserine birds other than waterblrds and raptors (see preceding tables).
Species
Spruce Grouse
(Dendragapus
canadensis)
Willow
Ptarmigan
(Lagopus
lagopus)
Rock
Ptarmigan
(Lagopus
mutus)
White-Tailed
Ptarmigan
(Lagopus
leucurus)
Ruffed Grouse
(Bonasa
umbellus)
Sharp-Tailed
Grouse
(Tympanuchus
phasianellus)
Abundance
in Alaska
Taiga
(Common,
Uncommon,
Rare,
Casual/
Accidental)
Cl,,6
C1'1*
pi, 16
U1'16
C1: limited
distribution
U1: limited
distribution12
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or
Unspecified Use = O) and Preference When Tested (Selected = [+], Neutral = [0], Avoided
= M)
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
O12
B16
B16
QU,fi,8,l
2
Mixed Taiga Landscape
g i,2,i6,n. grouncj nester, mixed and
coniferous forest, edges, burns,
blueberry barrens, clearings
O6'14, F2-12'13'15'17: use treeline habitats,
burns, and "muskeg" in fall and winter
B1'12: ground nester, wet willow shrub
in tundra
F1'12: use shrubby taiga openings on
hills in winter, sometimes sympatric
with willow ptarmigan
B1: ground nester in tundra
O6, F2"8'12: some use taiga in winter but
many remain above treeline
B1: ground nester in upland tundra
O2"6'18: may use conifers for cover2
B1'2'17: dry slopes in deciduous
woodlands, willow, alder
B 1,2,8,12. conjferous forest, scrub
woodlands, treeline, burns, edges,
openings
Black
Spruce
Q4,
BU7
F1
0s
gl.2,8,12
Wetlands
Mires
r> 1,'
-------
Table 34 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by nonpasserine birds other than waterbirds and raptors (see preceding tables).
Species
Sandhill Crane
(Grus
canadensis)
Semipalmated
Plover
(Charadrius
semipalmatus)
Killdeer
(Charadrius
vociferus)
Greater
Yellowlegs
(Tringa
melanoleuca)
Lesser
Yellowlegs
(Tringa
flavipes)
Solitary
Sandpiper
(Tringa
solitaria)
Spotted
Sandpiper
(Actitis
macularid)
Abundance
in Alaska
Taiga
(Common,
Uncommon,
Rare,
Casual/
Accidental)
C1: 150,000
to 200,000
migrants6'21
C1, U16 near
upper Susitna
R1
R1, U16 near
upper Susitna,
C'in
southcoastal
C1
U1'16
ci.w
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or
Unspecified Use = O) and Preference When Tested (Selected = [+], Neutral = [0], Avoided
= [-D
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
O5'21
B4'24
B23
Mixed Taiga Landscape
O18, B1'8'19'20: lowland tundra, scattered
taiga nesting in a mosaic of treed and
treeless wetlands, grassy meadows
B ' : gravel bars, beaches, moss
B : gravel shores, grasslands
F16: shorelines
O23: ponds and lakes
B24: mixed forest
O24: mixed forest24
B1'16: lakes and ponds, scattered
woodland, edges
B16'17'19: fluviatile shorelines
Black
Spruce
B20
B1
O23
Bw
0s
B,,23
Wetlands
Mires
O21, B2'23:
"bogs"2,
shrub
B22
B22
B2'17'22: shrub,
fens17
g4,17,22.23.
shrub, fens17,
black
4,23
spruce
B17*": black
spruce23,
shrub, fens
Bv#. N
"bogs"25
Other
O19: emergent
O1: emergent
g 1,3,16. 35^
emergent ,
j 16
meadow
g 1.3,5,24.
1 24
emergent ' ,
BSW3'5
0s, B1'3:
emergent1,
BSW3
O25: emergent
Food Occurs
in BSW
(Insects = I,
Fish = F,
Plants = P)
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
H: nesting,
foraging, roosting,
sparsely treed
BSW
L: nesting,
foraging, sparsely
treed BSW with
shorelines
L: nesting,
foraging,
graminoid BSW
H: nesting,
foraging, sparsely
treed BSW
H: nesting,
foraging, sparsely
treed BSW
H: nesting,
foraging, sparsely
treed BSW
L: nesting,
foraging, sparsely
treed BSW with
fluviatile
shorelines
-------
Table 34 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by nonpasserine birds other than waterbirds and raptors (see preceding tables).
Species
Upland
Sandpiper
(Bartramia
longicauda)
Whimbrel
(Numenius
phaeopus)
Hudsonian
God wit
(Llmosa
haemastica)
Western
Sandpiper
(Calidris
mauri)
Least
Sandpiper
(Calidris
minutilla)
Baird's
Sandpiper
(Calidris
bairdii)
Abundance
in Alaska
Taiga
(Common,
Uncommon,
Rare,
Casual/
Accidental)
U1, R16 near
upper Susitna
C',U16near
upper Susitna
A1: rare or
uncommon
regular
migrant"120
U'in
southcoastal
A'.U1
southcoastal
(coastal
migrant20)
U1, C'in
southcoastal
UU6
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or
Unspecified Use = O) and Preference When Tested (Selected = [+], Neutral = [0], Avoided
= N)
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
O20
Mixed Taiga Landscape
B 1.16.17,20. sparsely vegetate(j uplands,
dwarf shrub near scattered spruce, perch
in spruce
BM
-------
Table 34 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by nonpasserine birds other than waterbirds and raptors (see preceding tables).
Species
Pectoral
Sandpiper
(Calidris
melanotus)
Short-Billed
Dowitcher
(Limnodromus
griseus)
Long-Billed
Dowitcher
(Limnodromus
scolopaceus)
Common
Snipe
(Gallinago
gallinago)
Red-Necked
Phalarope
(Phalaropus
lobatus)
Belted
Kingfisher
(Ceryle alcyori)
Downy
Woodpecker
(Picoides
pubescens)
Abundance
in Alaska
Taiga
(Common,
Uncommon,
Rare,
Casual/
Accidental)
U1
A1 limited
distribution
C'in
southcoastal
U1
pl,16
pl,16
C1, U16 near
upper Susitna
UU6orC19
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or
Unspecified Use = O) and Preference When Tested (Selected = [+], Neutral = [0], Avoided
= [-])
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
B24
Mixed Taiga Landscape
F1'20: migrants use grassy edges of
ponds and lakes1'20
B1: nesting locations poorly known
F1'20: migrants use ponds and lakes1"20
F20: ponds, open water
B1'19'20: ground nester in tundra and
taiga
Ou,6,i7,i8,i9. perch in trees along shores
of fish-bearing waters
B19: nests in bank burrows
B8,i6,i7,i9,29ji. open woodlandj mixed and
deciduous forest, riparian willow and
alder
Black
Spruce
B1
g 1,4,5,24
Wetlands
Mires
O22
B2'17'22: fens17
p 17,22,23.
fens17, '
shrub17'23
black spruce23
O22
O22'25: [-]
"bogs"25
Other
O1: emergent
B1: wet tundra
O3: BSW
B1: wet tundra
glJ3,l<>.24.
emergent1'16'24,
BSW3"5'16
O16: meadow
ponds16
B 1,3,20. BSWMO
emergent1
Food Occurs
in BSW
(Insects = I,
Fish = F,
Plants = P)
F,I,P''8: also
take birds,
mammals
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
L: migration
foraging, BSW
with ponds
H: nesting,
foraging, sparsely
treed BSW
L: migration
foraging, BSW
with ponds
H: nesting,
foraging, sparsely
treed BSW
H: nesting, BSW
near ponds
L: foraging, BSW
with fish-bearing
waterbodies
L: foraging, open
BSW
-------
Table 34 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by nonpasserine birds other than waterbirds and raptors (see preceding tables).
Species
Hairy
Woodpecker
(Picoides
villosus)
Three-Toed
Woodpecker
(Picoides
tridactylus)
Black-Backed
Woodpecker
(Picoides
arcticus)
Northern
Flicker
(Colaptes
auratus)
Abundance
in Alaska
Taiga
(Common,
Uncommon,
Rare,
Casual/
Accidental)
UU6orC"
UU6
R1
C1, U16 near
upper Susitna
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or
Unspecified Use = O) and Preference When Tested (Selected = [+], Neutral = [0], Avoided
= H)
Nomvetlands or Mixed Wetlands and Nonwetlands
Shrub
B5
Mixed Taiga Landscape
06,,8 gw.w.17.19. mature mixed and
deciduous forest, woodland
O8'14, B1'2'16: mixed and coniferous
forest, woodlands, burns
O31, B1'16'17: mixed and coniferous forest
O6'18'31, Bu'17'29: burns with snags, open
coniferous and deciduous forest, open
woodlands, edges
Black
Spruce
Q4,5
B"
O8'2'
O4
Wetlands
Mires
O30: black
spruce
O23: black
spruce
(winter)
O22
B23: black
spruce, shrub
Other
O6'16: BSW
B3: BSW
O29: BSW
O3'6: BSW
Food Occurs
in BSW
(Insects = I,
Fish = F,
Plants = P)
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
L: foraging,
closed BSW
H: nesting,
foraging, all BSW
H: nesting,
foraging, closed?
BSW
H: nesting,
foraging, all BSW
1. Armstrong (1990)
2. Godfrey (1979)
3. Gillespie and Kendeigh (1982)
4. Carbyn (1971)
5. Spindler and Kessel (1980)
6. Cooper etal. (1991)
7. Larsen (1982)
8. Gabrielson and Lincoln (1959)
9. Bryant and Kuropat (1980)
10. Ellison (1989)
11. Ellison (1976)
12. Weeden and Ellison (1968)
13. Gruys (1993)
14. Kron (1975)
15. Viereck and Schandelmeier (1980)
16. Kessel et al. (1982)
17. Erskine (1977)
18. West and DeWolfe (1974)
19. J. Wright, Alaska Dep. Fish Game,
pers. commun.
20. P.O. Martin, U.S. Fish Wildl. Serv.,
pers. commun.
21. Kessel (1984)
22. Hogan and Tande (1983)
23. Spindler (1976)
24. Martin et al. (1995)
25. Gibbs etal. (1991)
26. Skeel (1983)
27. D.D. Gibson, Univ.
Alaska Mus., pers.
commun. to P.O. Martin,
U.S. Fish Wildl. Serv.
28. Kessel and Schaller
(1960)
29. Bent (1939)
30. Ewert(1982)
31.Murie(1963)
'
-------
Table 35. Use of black spruce wetlands (BSW) in Alaska by passerine birds.
Species
Olive-Sided
Flycatcher
(Contopus
borealis)
Western Wood-
Peewee
(Contopus
sordidulus)
Alder Flycatcher
(Empidonax
alnorum)
Hammond's
Rycatcher
(Empidonax
hammondii)
Tree Swallow
(Tachycineta
bicolor)
Violet-Green
Swallow
(Tachycineta
thalassina)
Bank Swallow
(Riparia riparid)
Abundance in
Alaska Taiga
(Common,
Uncommon,
Rare, Casual/
Accidental)
Tjl.12
U1, R12 near
upper Susitna
C1, U12 near
upper Susitna
C1
pl,12
ci,«
C\ U12 near
upper Susitna
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or Unspecified
Use = O)
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
O9,
B5'15
0s
O5
0s
Mixed Taiga Landscape
O6'9, B1'6'11'12'13: open mixed and coniferous
forest, scattered woodland and dwarf forest,
burns
O9, B1'2'6'8'11'12'13: open mixed, coniferous, and
deciduous forest, edges
B 1,1 1,12,13,14. alder md wj]low thickets, perch and
sing in conifers
O9'17, B1'2'11: riparian deciduous forest, open
conifers, mature mixed and coniferous forest
O6, F1'11'12: over water or moist ground,
successional shrubs, edges
B8: tree cavity nester
O6'14, F1'2'8'11: over open terrain, water, forest
canopy, and edges
B13: cliffs, block fields, crevices, other cavities
O9, F2'11'17: over water, open land, and edges
extending >5 km from nest
B8'11'12'13: earth cavities along banks
Black
Spruce
0S,8
B15
O4
B16
Wetlands
Mires
O2'7: "bogs"
B10'16: black
spruce16
o'°
D 2,8,10,11,16
b :
"bogs"2'8,
shrub"'16
O1'2: "bogs"
B10'16'19: black
spruce16, shrub19
B10'16: shrub16
O10
Other
B5: BSW
O6: BSW
B13: BSW
O5: BSW
B3'15: BSW3.
emergent15
Ow: BSW3,
marsh,
meadow1'2
F : low pH
O3'6: BSW
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
H: nesting,
foraging, open
BSW
H: nesting,
foraging, open
BSW
H: nesting,
foraging, all
BSW
L: foraging,
shrubby BSW
H: nesting,
foraging, all
BSW
H: foraging, all
BSW near
nesting habitat
H: foraging,
sparsely treed
BSW extending
>5 km from
nesting habitat
-------
Table 35 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by passerine birds.
Species
Cliff Swallow
(Hirundo
pyrrhonota)
Gray Jay
(Perisoreus
canadensis)
Black-Billed
Magpie (Pica
pica)
Common Raven
(Corvus corax)
Black-Capped
Chickadee
(Parus
atricapillus)
Boreal Chickadee
(Parus
hudsonicus)
Abundance in
Alaska Taiga
(Common,
Uncommon,
Rare, Casual/
Accidental)
C1, U12 near
upper Susitna
pl,12
C1: southern
Interior only
U12 near upper
Susitna
pl,12
C1, U12 near
upper Susitna
C1'12
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or Unspecified
Use = O)
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
0s
0s
Mixed Taiga Landscape
O6, F1'2'12'17: over open land and water closer to
nest than bank swallow
B8'11: mud nests on cliffs
O*'20, B1'8'11'12: mixed and coniferous forest,
woodlands, forest openings, treeline
O6'25: ground forager in dry mixed stands25
Bu,i U2,i3,25. nest in ]arger deciduous treeS)
scattered woodland and dwarf forest, mixed
riparian stands, treeline, shrub thickets, edges
O6'9'20, F1'2'11'12: scavenger and predator, uses
most habitats, prefers shorelines and coniferous
forest
B8: cliff, tree nester
O6'9'20, F1'": openings, edges, shrubs
B1'11'12: cavity nester, deciduous and coniferous
forest
O6'9'20, Flv2'8: willow, alder
Bu,8,i2,i3,i5. cavjty nesterj mixed, deciduous, and
coniferous forest
Black
Spruce
O4
B"
B13
O5
B4,ll
Wetlands
Mires
O10
O2'10'16: black
spruce (winter)16,
"bogs"2
B4'7'16: black
spruce4'16, bogs7
O10
O10
O10'16: black
spruce (winter)16
O10'16: black
spruce (winter)16
B': bogs
Other
F1*2: marsh
O12: BSW
B3-5'6: BSW
O12: BSW
O6: BSW
B3'12: BSW
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
M: foraging,
sparsely treed
BSW near
nesting cliffs
H: nesting,
foraging, all
BSW
1
L: foraging,
open BSW
within species
distribution
H: foraging, all
BSW
M: foraging,
shrubby BSW
H: nesting,
foraging, all
BSW
O
s
-------
Table 35 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by passerine birds.
Species
Ruby-Crowned
Kinglet (Regulus
calendula)
Mountain
Bluebird (Sialia
currucoides)
Gray-Cheeked
Thrush (Catharus
minimus)
Swainson's
Thrush (Catharus
ustulatus)
Hermit Thrush
(Catharus
guttatus)
American Robin
(Turdus
migratorius)
Varied Thrush
(Ixoreus naevius)
Abundance in
Alaska Taiga
(Common,
Uncommon,
Rare, Casual/
Accidental)
C13,U%ear
upper Susitna
R1
Cl,12
C1'12: abundant13
C1'12 (absent from
northern
interior24)
C1'12
C1'12
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or Unspecified
Use = O)
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
0s
B5
B5,15
Bs
Mixed Taiga Landscape
O^.F1: shrubs
g 1,2,11,12,13. nests jn conjferSi mixed and coniferous
forest
O6'8'17'21, B1'2'11'13': cavity nester, open woodland,
meadows, bums, openings, edges
O", B1'2'8'11'12'13'14: mixed and coniferous forest,
scattered woodland and dwarf forest, treeline,
burns, shrubs
O9, B1-2'8'11'12'13'15: mixed, coniferous, and
deciduous forest, tall shrubs, at lower elevations
than gray-cheeked thrush
O6, B1ASA8>11'12'13'22: mixed and deciduous forest,
young or open coniferous forest, edges, tall
shrubs, prefer deciduous habitats in central
Alaska but use BSW in Canada
O9, B1'2'11'12'13: mixed and deciduous woodlands,
scattered woodland and dwarf forest, shrubs,
openings, edges
O9, B1'2'8'12'13: shaded areas, damp mixed,
coniferous, and deciduous forest, prefers conifers
for nesting
Black
Spruce
B2,4,,5
B3'5'15
r> 4,5,11,15
D
B11
O1
g4,5,15
B1'2'8
Wetlands
Mires
B10'16: black
spruce16
B16: black spruce
B4'7'10'16: bogs7,
shrub16, black
spruce4
B4'7'10'11: bogs7,
black spruce4'11
B10'16: black
spruce, shrub16
Other
B3'5'12: BSW
Bs,«,u. BSW
O12: BSW
B5'6: BSW
B3: BSW
B3'5'6'12: BSW
O5'12: BSW
B6: BSW
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
H: nesting,
foraging, all
BSW
L: foraging,
sparsely treed
BSW
H: nesting,
foraging, all
BSW
H: nesting and
foraging, all
BSW
L (Alaska)13'22:
foraging,
shrubby BSW
H: nesting,
foraging, all
BSW
H: nesting,
foraging, open
to closed BSW
-------
Table 35 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by passerine birds.
Species
Bohemian
Waxwing
(Bombycilla
garrulus)
Northern Shrike
(Lanius
excubitor)
Orange-Crowned
Warbler
(Vermivora
celata)
Yellow Warbler
(Dendroica
petechia)
Yellow-Rumped
Warbler
(Dendroica
coronatd)
Townsend's
Warbler
(Dendroica
townsendi)
Blackpoll
Warbler
(Dendroica
striata)
Abundance in
Alaska Taiga
(Common,
Uncommon,
Rare, Casual/
Accidental)
C1, U12 near
upper Susitna
U1'12
C1, U12 near
upper Susitna
C1
pl,12
C1
U1, C12 near
upper Susitna
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or Unspecified
Use = O)
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
B5'6
B5,15
BJ*W
Mixed Taiga Landscape
Ov, F": successional stands
B 1,2,8,11,13. scattered W00(jiand and dwarf forest
Ofi'20, F2'8: preys on insects, birds, rodents
gU,8,i 1,12,13. nests in conifers or tall shrubs in
mixed and coniferous forest, scattered woodland
and dwarf forest, edges
o«,» B2,n,i2,i3,22. shrubs deciduous forest,
scattered woodland and dwarf forest
O6'9'17, B2'"'": riparian shrub, scattered woodland
and dwarf forest
O9, Bu'8'12'13: nests in conifers in open mixed,
coniferous, and deciduous forest, scattered
woodland and dwarf forest, tall shrub
O5'6'9'2': spruce-birch5, aspen21
B 1,2,5,8,13,24. ngsts in conjferSi mixed and
coniferous forest, sings from large spruce
O9, B1-2'8'11'12-13; mixed, deciduous, and coniferous
forest, scattered woodland and dwarf forest,
willow, alder
Black
Spruce
O17
g 1,2,4,5,8,
13
B15
B4*11
g4,15
Wetlands
Mires
B10'16: black
spruce, shrub16
B10'16: shrub16
B2'8: "bog--
margin tall shrub
B4,7,io,n,i6. bog7]
black spruce4'11'16
O10, B7'2': bogs7
Other
OM2: BSW
B5: BSW
O10
O12: BSW
g3Ais. BSW3,s
emergent15
Bls: emergent15
g3A6,U,12. gsw
B3'12: BSW
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
H: nesting,
foraging, open
BSW
M: nesting,
foraging, all
BSW
H: nesting,
foraging,
shrubby BSW
L: nesting,
foraging,
shrubby BSW
H: nesting,
foraging, open
BSW
L: foraging,
mixed BSW
H: nesting,
foraging, open
to closed BSW
-------
Table 35 (Cont'd). Use of black spruce wetlands (-BSW) in Alaska by passerine birds.
Species
Northern
Waterthrush
(Seiurus
noveboracensis)
Wilson's Warbler
(Wilsonia
pusilla)
American Tree
Sparrow (Spizella
arbored)
Chipping
Sparrow (Spizella
passe rind)
Savannah
Sparrow
(Passerculus
sandwichensis)
Fox Sparrow
(Passerella
iliaca)
Song Sparrow
(Melospiza
melodia)
Abundance in
Alaska Taiga
(Common,
Uncommon,
Rare, Casual/
Accidental)
CU2
CU2
Cl,12
U1: limited
distribution
(upper Tanana)
/-.1.12
pl,12
C'in
southcoastal
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or Unspecified
Use = O)
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
B12
B3,5,i2
g 3,5,6,12
QS.12
B15
B4
Mixed Taiga Landscape
O6'9, B1'2*11'12'13: tall shrub riparian, mixed and
deciduous forest edges, treeline
O9, B2'8'13: mixed woodlands, tall and medium
shrub thickets, treeline
B 1,2,8,11,12,13. stunted Spruce> iow to tau snrub
thickets, treeline
O9, g1'2'11'13: coniferous and deciduous forest,
scattered woodlands and dwarf forest, treeline,
thickets, openings, edges, grass meadows
O9, B1'11'12'13: ground nester, meadows, low shrub
with graminoid ground cover, scattered woodland
and dwarf forest, treeline
O9, B1'2'8'11'12'13: ground nester, medium and tall
shrub, scattered woodland and dwarf forest,
mixed forest, treeline
g 1,2,8,11,13. beaches, snrubby successional forest,
low riparian shrub, forest edges and openings
Black
Spruce
g4,l,
0s
0s
Wetlands
Mires
B2'8: "bog--
margin tall shrub
B2'8: shrubs near
"bogs"
B2'8'10'16: shrub16,
shrubs near
"bogs"2'8
B4'11'19: black
spruce
B2'11'16: "bogs"2,
black spruce,
shrub16,
graminoid
B l6: black spruce
B4'10'11'19: black
4,19
spruce ,
shrub11'19
Other
B3: BSW
B3: BSW
O5: BSW
B3'12: BSW
B11: BSW
O5: BSW
D 2,3,6,10,12
D :
BSW3'6'12,
emergent2
O3'12: BSW
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
L: foraging,
shrubby BSW
M: nesting,
foraging,
shrubby BSW
H: nesting,
foraging,
shrubby BSW
H: ^nesting,
foraging, open
BSW
H: nesting,
foraging, open
graminoid BSW
H: nesting,
foraging,
shrubby BSW
H: nesting,
foraging,
shrubby BSW
within species
distribution
-------
Table 35 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by passerine birds.
Species
Lincoln's
Sparrow
(Melospiza
lincolnii)
Golden-Crowned
Sparrow
(Zonotrichia
atrlcapilld)
White-Crowned
Sparrow
(Zonotrichia
leucophrys)
Dark-Eyed Junco
(Junco hyemalis)
Rusty Blackbird
(Euphagus
carolinus)
Pine Grosbeak
(Pinicola
enucleator)
White-Winged
Crossbill (Loxia
leucoptera)
Abundance in
Alaska Taiga
(Common,
Uncommon,
Rare, Casual/
Accidental)
C1, U12 near
upper Susitna
UU2, C1 in
southcoastal
,-.1,12
Cl,,2
U1, R12 near
upper Susitna
U1'12
U1 (irregular
nomad"), C12
near upper
Susitna
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or Unspecified
Use = O)
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
O12
g 5,6,15
g 34,6,12,
15
B5
g34,6
O5
Mixed Taiga Landscape
O9, B1'2'8-11'13'22: moist meadows, low to tall
riparian shrub, scattered woodland and dwarf
forest, low spruces
g 1,11,12,13. groun(j nesterj iow shrub, scattered
woodland and dwarf forest primarily near treeline
O9, B1'2'8'11'12'13: ground nester, low to tall shrub,
scattered woodland and dwarf forest, edges,
treeline
O9, B1'2'8'11'12'13: young to mature mixed,
coniferous, and deciduous forest, openings,
edges, scattered woodland and dwarf forest, tall
shrub, treeline
O9, Bll2'8'1U3: wet woods, riparian shrub,
scattered woodland and dwarf forest, shrubby
successional forest
O9, BI>2'8>n'13: nests in conifers, open coniferous
and mixed forest, edges, scattered woodland and
dwarf forest
O20, B1'2'8'11'13: nests in conifers, open coniferous
and mixed forest, edges, openings, scattered
woodland and dwarf forest
Black
Spruce
O5
g 2,4,8,15
B5'15
g 1,2,3,44,
8,15
0s
B2'8
O4
0s
B4
Wetlands
Mires
o 2,8,10,11,16,19
b :
"bogs"2'8, black
spruce16'1',
shrub11'16
g,0
B10'16: black
spruce, shrub16
B4,7,,0,,,,,6. b]ack
spruce4'11'16,
shrub16
B2,8,,o,n,,6. black
spruce11'16,
shrub16, "bogs"2'8
B : black spruce
O4, B10
Other
O13-22: BSW
B1-23'15:
emergent
g 34,6,12, 15.
BSW34'6'12,
emergent15
g 3,44,6,11,12,15.
gSW3,44,6,li;i2j
emergent15
O12: BSW
B2'3'8'13: BSW3,
emergent2'8'13
B3'6: BSW
O12: BSW
B6: BSW
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
H: nesting,
foraging, open
BSW
M: nesting,
foraging,
shrubby BSW
near treeline
H: nesting,
foraging, open
BSW
H: nesting,
foraging, all
BSW
H: nesting,
foraging,
shrubby BSW
near water
H: nesting,
foraging, open
BSW
H: nesting,
foraging, open
BSW
i
-------
Table 35 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by passerine birds.
Species
Common Redpoll
(Carduelis
flammea)
Hoary Redpoll
(Carduelis
hornemanni)
Pine Siskin
(Carduelis pinus)
Abundance in
Alaska Taiga
(Common,
Uncommon,
Rare, Casual/
Accidental)
C1'12: abundant12
R1 in summer but
C in winter and
spring1'8'21
R1 (irregular near
upper Susitna12),
C'in
southcoastal
Habitat Use (Breeding or Potentially Breeding = B, Foraging = F, Generally Occurring or Unspecified
Use = O)
Nonwetlands or Mixed Wetlands and Nonwetlands
Shrub
O6
B5'12
Mixed Taiga Landscape
O9>20, B2'11'12'13: low to tall thickets, all forest
habitats including scattered woodland and dwarf
forest, treeline
O : often occur with common redpoll in winter '
F13: paper birch primary winter food
B1'13'16: primarily tundra nester, low/medium
shrub, mixed woodland
O5lW1: tall spruce
F : deciduous trees and ground when not nesting
g 1,2,8,11,13. nests jn coniferSj coniferous and mixed
forest, treeline
Black
Spruce
B5
Wetlands
Mires
B16: black
spruce, shrub
B10
Other
O6: BSW
D 3,5,10,12
D '.
BSW3"5'12
Probability
Species Uses
BSW
(Low = L,
Medium = M,
High = H)
H: nesting,
foraging, all
BSW
L: winter
foraging,
shrubby BSW
L: foraging,
forested BSW
'
3
Ca
a"
f
s
3
5^
B"
I.Armstrong (1990)
2. Godfrey (1979)
3. Gillespie and Kendeigh (1982)
4. Carbyn (1971)
5. Spindler and Kessel (1980)
6. Cooper etal. (1991)
7. Larsen (1982)
8. Gabrielson and Lincoln (1959)
9. West and DeWolfe (1974)
10. Hogan and Tande (1983)
ll.Erskine(1977)
12. Kessel et al. (1982)
13. J. Wright, Alaska Dep. Fish
Game, pers. commun.
14. Murie (1963)
15. Martin etal. (1995)
16. Spindler (1976)
17. White and Haugh (1969)
18. Blancher and McNichol (1991)
19. Ewert(1982)
20. Kron (1975)
21. Kessel and Springer (1966)
22. P.O. Martin, U.S. Fish Wildl.
Serv., pers. commun.
23. Walley (1989)
24. O.K. Swanson, Nat. Resour.
Conserv. Serv., pers. commun.
25. R. Sinnott, Alaska Dep. Fish
Game, pers. commun.
-------
Table 36. Frequently occurring avion species in Alaskan and Canadian black spruce forests and wetlands (all waterbirds except gulls, all raptors, and spe-
cies not occurring in interior Alaska are excluded).
Species (number of times
species reported for nine
sites or site types)
Dark-Eyed Junco (7)
Common Snipe (7)
Yellow-Rumped Warbler (6)
Lesser Yellowlegs (5)
Ruby-Crowned Kinglet (5)
Gray-Cheeked Thrush (5)
American Robin (5)
White-Crowned Sparrow (5)
Common Redpoll (5)
Gray Jay (4)
Swainson's Thrush (4)
Bohemian Waxwing (4)
Savannah Sparrow (4)
Solitary Sandpiper (3)
Boreal Chickadee (3)
Lincoln's Sparrow (3)
Rusty Blackbird (3)
Spruce Grouse (2)
Sandhill Crane (2)
Greater Yellowlegs (2)
Three-Toed Woodpecker (2)
Northern Flicker (2)
Olive-Sided Flycatcher (2)
Alder Flycatcher (2)
Hermit Thrush (2)
Orange-Crowned Warbler (2)
Blackpoll Warbler (2)
Black
Spruce
Forest -
Upper
Xanana
Valley,
Alaska1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Common
Species in
Canadian
Black
Spruce
Forest2
X
X
X
X
X
X
X
X
X
X
X
Black
Spruce
Mire -
Fairbanks,
Alaska3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Black
Spruce Bog
- Upper
Tanana
Valley,
Alaska1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Black
Spruce
Dwarf
Forest -
Upper
Susitna
Valley,
Alaska4
X
X
X
X
X
X
X
X
X
X
X
Common
Species in
Canadian
Open Black
Spruce
Bogs2
X
X
X
X
Tussock-
Low Shrub
Mire-
Fairbanks,
Alaska1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Common
Species in
Canadian
Open
Shrub-
Sedge Bogs2
X
X
X
X
X
X
X
Common
Species in
Canadian
Fens2
X
X
X
X
X
§
-------
Table 36 (Cont'd). Frequently occurring avian species in Alaskan and Canadian black spruce forests and wetlands (all waterbirds except gulls, all raptors,
and species not occurring in interior Alaska are excluded).
Species (number of times
species reported for nine
sites or site types)
American Tree Sparrow (2)
Chipping Sparrow (2)
Fox Sparrow (2)
Bonaparte's Gull (1)
Mew Gull (1)
Least Sandpiper (1)
Short-Billed Dowitcher (1)
Tree Swallow (1)
Violet-Green Swallow (1)
Song Sparrow (1)
Pine Grosbeak (1)
Black
Spruce
Forest -
Upper
Xanana
Valley,
Alaska1
Common
Species in
Canadian
Black
Spruce
Forest2
X
Black
Spruce
Mire -
Fairbanks,
Alaska3
X
X
X
X
Black
Spruce Bog
- Upper
Tanana
Valley,
Alaska
Black
Spruce
Dwarf
Forest -
Upper
Susitna
Valley,
Alaska4
X
X
Common
Species in
Canadian
Open Black
Spruce
Bogs
X
Tussock-
Low Shrub
Mire-
Fairbanks,
Alaska1
X
X
Common
Species in
Canadian
Open
Shrub-
Sedge Bogs2
X
Common
Species in
Canadian
Fens2
X
X
X
Co
S"
ri
S
I
1. Spindler and Kessel (1980)
2. Erskine (1977)
3. Spindler (1976)
4. Kessel etal. (1982)
r
-------
Table 37. Use of black spruce wetlands (BSW) in Alaska by insectivores, chiropterans, rodents, and lagomorphs. Other habitat abbreviations are Mixed Taiga Land-
scape (MTL), Black Spruce Forest (BSF), Mire (M), Bog (B), Fen (F), Swamp (S), and Emergent (E).
Species
Alaska Distribution (Arctic/Western = A, Interior =
I, Southern = S) and General Habitat Preferences
Habitats Where Observed
or Captured
Prey or Food Potentially Occurs in
BSW
Probability
Species Uses BSW
Common Shrew
(Sorex cinereus)
I, S1: occurs in talus slopes, forests, open country,
brushland, wet mossy areas, marshes, moist areas1'2'3'61
MTL4, BSF5'61, B6: heath-
moss
BSW61: mature moss/shrub
F7, S7: black spruce-
tamarack
Shrews feed on invertebrates, often in
moist habitats*
H: breeding,
foraging, all BSW
Pygmy Shrew
(Sorex hoyi)
I, S (limited distribution)1: forested and open areas2;
prefers drier habitats than other shrews1 but uses bogs
and marshes"; moisture preference may change from
wet in spring to drier in summer11
BSF4I,S7'II,E7'1I,B7111:
heath-moss7, alpine11
F7: willow/alder (birch)
Shrews feed on invertebrates, often in
moist habitats"
H: breeding,
foraging, BSW
with mixed
moisture conditions
Dusky Shrew
(Sorex
monticolus)
I, S1: moist environments1, marshes, coniferous forests,
heather2
MTL3: moist grass, deep
moss, dwarf alder
BSF61, BSW61: mature
moss/shrub
E , F : willow-alder (birch)
Shrews feed on invertebrates, often in
moist habitats"
H: breeding,
foraging, all BSW
Northern Water
Shrew (Sorex
palustris)
S (Cook Inlet area, may penetrate Copper River basin
from Canada)1'10: damp riparian areas1, "bogs"2'6;
prefers moss near flowing water ; greatest densities
occur in riparian marsh and shrub and in
willow/graminoid communities7'10
B7: sedge-moss, heath-moss
S7: black spruce-tamarack
Shrews feed on invertebrates, often in
moist habitats'
H: breeding,
foraging, riparian
BSW
Tundra Shrew
(Sorex
tundrensls)
A1: wet or dry tundra1, species sometimes lumped with
1.2 3 9
taiga populations as the arctic shrew (S. arcticus) '
Shrews feed on invertebrates, often in
moist habitats"
L: foraging,
sparsely treed BSW
Little Brown
Bat (Myotis
lucifiga)
I (southern), S1'3: hunts over water, riparian zones
along rivers, and forested areas between roosts and
primary feeding area12'13'14; nursery colonies often close
to riparian zones
Feeds on aquatic insects (especially
chironomids), moths, and beetles12'13
M: foraging over
BSW near rivers
within species
distribution
Red Squirrel
(Tamiasciurus
hudsonicus)
I, S1'15: coniferous or mixed forest, swamps
1,2,16
BSF
17,18,19,211,21
Prefers white spruce seed20"21, but
black spruce more dependably
produces cones; squirrels in black
spruce feed nearly exclusively on
black spruce seeds21
H: breeding,
foraging, well-treed
BSW
-------
Table 37 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by insectivores, chiropterans, rodents, and lagomorphs. Other habitat abbreviations are Mixed
Taiga Landscape (MTL), Black Spruce Forest (BSF), Mire (M), Bog (B), Fen (F), Swamp (S), and Emergent (E).
Species
Alaska Distribution (Arctic/Western = A, Interior =
I, Southern = S) and General Habitat Preferences
Habitats Where Observed
or Captured
Prey or Food Potentially Occurs in
BSW
Probability
Species Uses BSW
Northern Flying
Squirrel
(Glaucomys
sabrinus)
I (central), S (Cook Inlet) : prefers conifers; use mixed,
coniferous, and deciduous forest22; nest in cavities,
witches' broom, or balls of plant material ("drays") in
foliage near red squirrel middens; prefer spruce >8 m
for gliding
MTL : white spruce-paper
birch
Prefers fungi and lichens raided from
red squirrel middens23 but also eats
bark, fruit, berries, and insects ; spruce
cones not selected over alternatives24
L: breeding,
foraging, forested
(trees >6 m) BSW
Beaver (Castor
canadensis)
I, Sus: uses waterbodies in proximity to preferred
forage (aquatic vegetation, deciduous trees and
shrubs)9'25'26'27'28, including riparian sedge-willow mats,
thaw lakes with peat and sedge mats near birch stands,
and kettle lakes with pond lily (Nuphar spp.) in black
spruce/5/? hagnum21
Pond lily and buckbean can support
beavers where other foods are
scarce ' ; spruce needles sometimes
consumed26 but cuttings in caches may
not be eaten
M: breeding,
foraging, BSW
with deep ponds or
flowing water and
deciduous
component, pond
lily, or buckbean
Meadow
Jumping Mouse
(Zapus
hudsonius)
I (southern), S1: occupies meadows but has broad
habitat preferences2 including grass, marsh, and open
woods1; thick riparian or pond-edge vegetation, thick
herbaceous cover in forests9'48; avoids sparse cover48
BSF : burned and
unburned stands
MTL4: surrounding a lake
H: breeding,
foraging, graminoid
BSW within
species distribution
Northern Red-
Backed Vole
(Clethrionomys
rutilus)
A, I, S1: some consider southern red-backed vole (C.
gapperi) conspecific with C. rutilits3'29; C. gapperi uses
muskeg, sedge marsh, "bog" ; C. rutilus occupies
many habitats30 from dry tundra to bog mat with
greatest density in dwarf shrub, alder, and vegetated
talus ; thick moss favorable for overwintering
MTL30'31'32'33'39: shrub
tundra, successional
deciduous forest, white
spruce, black spruce, balsam
poplar
BSF61, M39, BSW39'61:
mature moss/shrub
(abundant)61
Berries
H: breeding,
foraging, all BSW
Bering Collared
Lemming
(Dicrostonyx
rubricatus)
A1: arctic and alpine tundra
E : low, moist or wet cotton
grass meadows in mountain
valley bottoms
L: breeding,
foraging, graminoid
BSW near tundra
Brown
Lemming
(Lemmus
trimu.crona.tus)
A, I, S1: damp arctic tundra and drier alpine tundra2"3'9
BSW31: post-fire stand
Consumes graminoids (e.g., Carex,
Eriophorum) and mosses other than
Sphagnum
M: breeding,
foraging, graminoid
or post-fire BSW
-------
Table 37 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by insectivores, chiropterans, rodents, and lagomorphs. Other habitat abbreviations are Mixed
Taiga Landscape (MTL), Black Spruce Forest (BSF), Mire (M), Bog (B), Fen (F), Swamp (S), and Emergent (E).
Species8
Long-Tailed
Vole (Microtus
longicaudus)
Singing Vole
(Microtus
miurus)
Tundra Vole
(Microtus
oeconomus)
Meadow Vole
(Microtus
pennsylvanicus)
Yellow-
Cheeked Vole
(Microtus
xanthognathus)
Muskrat
(Ondatra
zibethicus)
Northern Bog
Lemming
(Synaptomys
borealis)
Alaska Distribution (Arctic/Western = A, Interior =
I, Southern = S) and General Habitat Preferences
I (eastern)40: occupies a variety of habitats, some of
which are dry, rocky, or grassy areas far from
water113135; low, wet, spruce woodland3; grassy areas in
forest , riparian areas, marshes, willow-alder stands,
white spruce forest40
A, I (mountainous areas)1'35: occupies alpine tundra9
A, I, S1: moist and wet tundra2'9, sedge meadow, bogs,
and Sphagnum3, alpine tundra, subalpine shrub tundra,
marsh30; high niche overlap with meadow voles30
A (part), I, S1: moist or wet grassy meadows and
shrublands near waterbodies, including marsh, bog
mats, swamps, and forested areas1'2'3'6'9'35; moist
grassland optimum habitats36
I1: black spruce forest, bog, forest-tundra, runways in
tree or shrub communities, sedges, grassy taiga, post-
fire successional stands, graminoid lakeshores, and
riparian areas1'2"4'"5'41'42-43'61
I, S1: waterbodies and marshes2 deep enough for
overwintering9 but can occur >3 km from water ;
usually present at beaver colonies26
I, S1: wet environments, alpine and subalpine
meadows, muskeg, Sphagnum bogs, ericaceous
vegetation, sedge meadows, and marshes112'3'6; construct
nests in Sphagnum mounds or graminoid tussocks9
Habitats Where Observed
or Captured
MTL3: rocky mountainsides
primary habitat in Yukon
BSW31: wet post-fire stand
BSF37: post-fire stand
MTL430: shrub birch30
BSF31"37'38: post-fire stands
E30"39: marsh30, bluejoint
meadow39
MTL3'61: Sphagnum riparian
area in an old burn3
E39: bluejoint meadow
BSF4'61, BSW61: mature
moss/shrub
B44: Wisconsin
BSF5: upland stand
MTL4: surrounding a lake
BSW31: post-fire stand
Prey or Food Potentially Occurs in
BSW
Horsetail (Equisetum spp.) or fireweed
(Epilobium spp.) rhizomes for winter
food and heavy moss over deadfall for
easy burrowing are key factors in
habitat selection37; graminoids, forbs61
Eats cattails, bulrush, pondweed
(Potamageton spp.), horsetail, and
aquatic invertebrates9'45'46
Probability
Species Uses BSW
L: breeding,
foraging, grassy
BSW within
species distribution
L: BSW near
treeline
H: breeding,
foraging, graminoid
or shrubby BSW
H: breeding,
foraging, graminoid
or shrubby BSW
H: breeding,
foraging, BSW
with abundant
rhizomes and good
burrowing
conditions
M: breeding,
foraging,
minero trophic
BSW with
sufficient water
depth for
overwintering
H: breeding,
foraging, all BSW
-------
Table 37 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by insectivores, chiropterans, rodents, and lagomorphs. Other habitat abbreviations are Mixed
Taiga Landscape (MTL), Black Spruce Forest (BSF), Mire (M), Bog (B), Fen (F), Swamp (S), and Emergent (E).
ci • a
species
Alaska Distribution (Arctic/Western = A, Interior =
I, Southern = S) and General Habitat Preferences
A (some), I, S : conifer, aspen, and mixed forests;
bmshlands, open tundra, and riparian corridors1'2'9'49'50
Habitats Where Observed
or Captured
Prey or Food Potentially Occurs in
BSW
Probability
Species Uses BSW
Porcupine
(Erethiion
dorsatum)
B52'57: black spruce52, bog
margins57
BSF58: stable hare habitat
MTL5738: alder thickets-
forest openings57
Feeds on shrubs and trees, including
spruce, and herbaceous vegetation,
including sedges and aquatic plants50
H: breeding,
foraging, all BSW
Snowshoe Hare
(Lepus
americanus)
A, I, S1: mixed and coniferous forests, swamps,
thickets1'2''''9'51; prefers brushy understory for winter
food and cover, overstory may be scattered or absent52;
uses most available habitats during cyclic population
highs but only dense cover during lows53'54'55; uses
opens stands in summer but dense cover in winter53;
hares have poor survival in open habitats, black spruce
and shrub thickets protect hares from predators52153'54'56
58
Food includes blueberry, Labrador-tea,
willows, paper birch, black spruce,
and alder59'60; black spruce is not
preferred but is most abundant food in
hare habitat and about half of winter
hare diet59
H: breeding,
foraging, cover, all
BSW (preferred
type varies by
season and cyclic
population level)
1. Manville and Young (1965)
2. Burt and Grossenheider (1964)
3. Youngman (1975)
4. Douglass (1977)
5. Martell (1984)
6. Larsen (1982)
7. Wrigleyetal. (1979)
8. Jarrelletal. (1994)
9. Nowak and Paradise (1983)
10. Beneski and Stinson (1987)
11. Long (1974)
12. Fenton and Barclay (1980)
13. Humphrey (1982)
14. B. Lawhead, ABR, Inc., pers.
commun.
15. Flyger and Gates (1982)
16. Larsen (1982)
17. Prevostetal. (1988)
18. Wood (1967)
19. Modaferri (1972)
20.Nodler(1973)
2 I.Kelly (1978)
22. Wells-Gosling and Heaney
(1984)
23. Mowrey and Zasada (1984)
24. Brink (1964)
25. Hill (1982)
26. Hakala(1952)
27. Dennington and Johnson (1974)
28. Jenkins and Busher (1979)
29. Merritt(1981)
30. Krebs and Wingate (1985)
31. West (1982)
32. Whitney and Feist (1984)
33. Gilbert and Krebs (1991)
34. West (1977)
35. Johnson and Johnson (1982)
36. Reich (1981)
37. Wolff and Lidicker (1980)
38. Martell (1984)
39. Osborne(1987)
40. Smolen and Keller (1987)
41.Lensink(1954)
42. Douglass and Douglass (1977)
43. Wolff and Lidicker (1981)
44. Jackson (1914 in Larsen 1982)
45. Willner etal. (1980)
46. Perry (1982)
47. Batzli and Pitelka (1983)
48.Whitaker(1972)
49. Woods (1973)
50. Dodge (1982)
51. Bittner and Rongstad (1982)
52. Keith etal. (1984)
53. Wolff etal. (1979)
54. Wolff (1980)
55. Boutin etal. (1985)
56. Parker (1984, 1986)
57. Keith (n.d.)
58. Fox and Bryant (1984)
59. Wolff (1978a)
60.Trapp(1962)
61.Swanson(1996)
-------
Table 38. Use of black spruce wetlands (BSW) in Alaska by carnivores. Other habitat abbreviations are Mixed Taiga Landscape (MTL), Black Spruce Forest (BSF),
Mire (M), Bog (B), Fen (F), Swamp (S), and Emergent (E).
Species1
56
Alaska Distribution (Arctic/Western = A, Interior = I,
Southern = S) and General Habitat Preferences
Habitats Where
Observed or
Captured
Prey or Food Potentially Occurs in BSW
Probability
Species Uses
BSW
Arctic Fox
(Alopex
lagopus)
A, S (some)1: arctic and alpine tundra in coastal areas4;
regular inland migrations, reported from Eurasia, do not
occur in Alaska7, but records exist from inland tundra5'8
and taiga locations1'6
MTL1'6: Kenai
Peninsula,
Manitoba6,
southern foothills
of Brooks Range1
Foxes moving inland feed on lemmings4
L: foraging,
sparsely treed
BSW near
coastal tundra
Coyote
(Canis
latrans)
A (some), I, Sl|9''°: broad ecological tolerances1, prefer
grassland, brush, and broken forests4;
Consume lagomorphs, rodents, ungulates, birds,
invertebrates, fruit, and carrion4'*'"'12
H: foraging, all
BSW
Wolf (Canis
lupus)
A, I, S1: distribution follows prey availability rather than
specific habitat characteristics14, occupies most natural
habitats, including mires, in the absence of human
persecution and habitat modification
M : Minnesota
13,14
Primarily prey on ungulates, including moose,
caribou, and muskox (Ovibos moschatus), but
some consistently take beaver4'13
H: foraging, all
BSW
Red Fox
(Vulpes
vulpes)
A, I, Sw: broad tolerances, prefers habitat mosaics,
ecotones, and other areas of habitat diversity
E1
2,3,4
Consume small mammals (snowshoe hare, red
squirrel, ground squirrel, lemmings, voles), birds
(ptarmigan, passerines), insects, and fruits3'4>5
H: foraging, all
BSW
Lynx (Lynx
canadensis)
A (some), I, S1: taiga forests and openings, swamps, black
spruce "bogs," brushland, marsh, and shrub barrens1'2'15'16;
avoid post-fire successional stands for >15 yr following
fire but abundant where post-fire successional stands are
mixed with stands of mature spruce17
Primarily prey on snowshoe hares16, generally
occur wherever hares are found1; also eat
squirrels, shrews, voles, birds, beaver, moose,
caribou, muskrat, and fish (includes
carrion)
H: breeding,
foraging, all
BSW
15,15,16,44
River Otter
(Lontra
canadensis)
A (some), I, S1: freshwater streams and lakes, estuaries,
and littoral marine waters4'18; select watersheds containing
abundant active or abandoned beaver ponds, avoided
headwater areas (Maine)19; use forested, scrub-shrub, and
other wetlands (Massachusetts)20
Primarily consume fish but also take crustaceans,
aquatic insects, and amphibians, as well as
occasional birds and small mammals18
L: foraging,
BSW bordering
fish-bearing
waterbodies
Wolverine
(Gulo gulo)
A, I, S1'21: forest, mountains, and tundra1'4; and favors
marshy areas22; prefer spruce to alpine tundra in winter23
MTL": mixed
spruces
Feed on moose (mainly carrion), caribou (mainly
carrion), lagomorphs, beaver, marmots, red
squirrel, ground squirrels, small rodents,
ptarmigan, waterfowl, eggs, carrion, and
berries3'4'22'23'24
H: breeding,
foraging, all
BSW
§
-------
Table 38 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by carnivores. Other habitat abbreviations are Mixed Taiga Landscape (MTL), Black Spruce
Forest (BSF), Mire (M), Bog (B), Fen (F), Swamp (S), and Emergent (E).
Species '
Alaska Distribution (Arctic/Western = A, Interior = I,
Southern = S) and General Habitat Preferences
Habitats Where
Observed or
Captured
Prey or Food Potentially Occurs in BSW
Probability
Species Uses
BSW
Marten
(Martes
americana)
I, S1: mature mixed or coniferous forest1'2'25; winter den
sites often in red squirrel middens in stands containing
white spruce27; avoids some clearcuts28'29 but uses burns
(use higher in younger seres) in a landscape of black
spruce forest, treeless bogs, and wet meadows30"12; uses
spruce forests and woodlands more frequently and shrub
habitats less frequently than expected; significantly more
snow digging and tracks in black spruce woodland than
expected26
%26,33,34
Consume voles (often red-backed)
snowshoe hares when abundant35, bog lemmings,
red squirrels, arctic ground squirrels, northern
H: breeding,
foraging, all
BSW
flying squirrels26, fruits, birds 26'31,
and insects
Ermine
(Mustela
erminea)
A, I, S1'36: forest and shrub habitats2, open tundra4; prefers
successional sites and ecotones, scrub, riparian habitats,
marshes, and alpine meadows; distribution follows prey37
BSF38: post-fire
sere
Prey primarily rodents and lagomorphs ; other
items include fish, amphibians, birds, insects, and
small amounts of vegetation
36,37
H: breeding,
foraging, all
BSW
Least Weasel
(Mustela
nivalis)
A, I, S (some)1: meadows, emergent wetlands, scrub-
shrub, riparian areas, and woodland2"36'39; habitats resemble
those used by ermine"; local distribution follows prey39
Primarily prey on red-backed and meadow voles
and lemmings, but males take hares when rodent
abundance low36'39
H: breeding,
foraging, all
BSW
Mink
(Mustela
visori)
A (most), I, S1: wetlands including bogs, swamps,
marshes, and margins of waterbodies but also occurs in
M43, BSW43
forests " ' ; shorelines of large waterbodies and
interconnected waterbody complexes and beaver/muskrat
trails40'42'43
Consume voles, brown and bog lemmings,
snowshoe hare, muskrat, red squirrel, birds
(including waterfowl and willow ptarmigan),
eggs, fish, and frogs2'4'40'42'43
H: breeding,
foraging, BSW
bordering lakes,
rivers, streams,
sloughs
Black Bear
(Ursus
americanus)
A (some), I, S1: forests, swamps, and mountains with thick
understory vegetation and abundant food; occasionally use
tundra1'4'45; spruce forest (white and black) used in
proportion to availability, birch-aspen and willow-alder
used more than expected, and heath and marsh used less
than expected; den in spruce, willow-alder, birch-aspen,
and heath but significantly favor willow-birch and tend to
avoid heath47
BSW46: with bog
blueberry
Consume more plants than animals: shoots of
herbaceous plants, buckbean, fruits and berries,
fish, invertebrates, rodents, snowshoe hares,
moose calves, birds, eggs, and carrion4'45'46'48
H: breeding,
foraging, all
BSW but favor
well-treed BSW
and BSW with
abundant fruits
and berries
-------
Table 38 (Cont'd). Use of black spruce wetlands (BSW) in Alaska by carnivores. Other habitat abbreviations are Mixed Taiga Landscape (MTL), Black Spruce
Forest (BSF), Mire (M), Bog (B), Fen (F), Swamp (S), and Emergent (E).
Species'
Alaska Distribution (Arctic/Western = A, Interior = I,
Southern = S) and General Habitat Preferences
Habitats Where
Observed or
Captured
Prey or Food Potentially Occurs in BSW
Probability
Species Uses
BSW
Brown Bear
(Ursus
arctos)
A, I, S : broad habitat tolerances, prefers open terrain
including tundra and coastal areas, swamps, streams,
forests1'4; in an area of north-aspect slopes supporting
black spruce, females prefer habitats above treeline, but
males significantly prefer elevations below treeline50;
heavy predation on moose calves suggests that brown
bears are present in wetland habitats such as the Tanana
Flats55; bears seasonally seek bog blueberry in cotton grass
tussocks and black spruce woodland52
MTL": low
forested flats along
Kantishna River
Consume graminoids, common horsetail
(Equisetum arvense), Hedysarum spp. roots, bog
blueberry, buffaloberry (Shepherdia canadensis),
calf moose (significant numbers53"54) snowshoe
hare, and carrion in spring and early summer;
forage on Hedysarum spp roots, fruits and berries,
graminoids, and salmon in late summer and
fall4'49'51"52
H: foraging, all
BSW
1. Manville and Young (1965)
2. Burt and Grossenheider (1964)
3. Samuel and Nelson (1982)
4. Nowak and Paradise (1983)
5.Eberhardt(1977)
6. Underwood and Mosher (1982)
7. Chesemore (1967)
8. E. Follmann, Univ. Alaska, pers.
commun.
9.Bekoff(1977)
10. Bekoff(1982)
11. Post (1976)
12. Harrison (1983)
13. Mech(1974)
14. Paradise and Nowak (1982)
15. McCord and Cardoza (1982)
16.Tumlison(1987)
17. Stephenson (1984)
18. Toweill and Tabor (1982)
19. Dubucetal. (1990)
20. Newman and Griffin (1994)
21. Pasitschniak-Arts and Lariviere
(1995)
22. Wilson (1982)
23. Gardner (1985)
24. Magoun (1985)
25. Strickland etal. (1982)
26. Buskirk (1983)
27. Buskirk (1984)
28. Snyder and Bissonette (1987)
29. Steventon and Major (1982)
30. Magoun and Vernam (1986)
3 I.Strickland etal. (1982)
32. Paragi etal. (1994)
33. Douglass etal. (1983)
34. Koehler and Hornocker (1977)
35. Raine (1987)
36. Svendsen (1982)
37. King (1983)
38. Wolff and Lidicker (1980)
39. Sheffield and King (1994)
40. Linscombe et al. (1982)
41.Larsen(1982)
42. Arnold and Fritzell (1990)
43. Harbo (1958)
44. Youngman(1975)
45. Pelton (1982)
46. Hatler(1967, 1972)
47. Hechtel(1991)
48. Schwartz and Franzmann
(1991)
49. Craighead and Mitchell (1982)
50. T. Boudreau, Alaska Dep. Fish
Game, pers. commun.
51. McCarthy (1989)
52. Valkenburg(1976)
53. Gasaway etal. (1992)
54. Ballard etal. (1991)
55. Gasaway et al. (1983)
56. Jarrell etal. (1994)
<>o
r>'
'
-------
Table 39. Use of black spruce wetlands (BSW) in Alaska by cervid artiodactyls (moose, caribou).
Species37
Alaska Distribution (Arctic/Western = A, Interior = I, Southern = S) and
General Habitat Preferences
Prey or Food Potentially Occurs in BSW
Probability Species
Uses BSW
Moose (Alces
alces)
A (most), I, S (most)1: taiga, shrub riparian tundra1'2; prefer serai
communities from fire or alluviation that provide abundant, high-quality
forage3'415; cows select tall cover in spruce and deciduous stands during
calving on the Tanana Flats8; calve on muskeg hummocks for predator
avoidance ; proximate coniferous cover increases the value of successional
stands to moose ; select lowland black spruce during late summer in
Minnesota ; use black spruce muskeg during late winter in Alberta11; some
open black spruce has willow component13'14; select aquatic-herbaceous
habitat during May and June8
Forage in riparian willow, treeline resin birch and
willow, lowland decadent willow, spruce
forest'' ; fire stimulates willow production in
burned black spruce stands9; eat forbs and aquatic
vegetation in summer3'10'12, which supply sodium2
H: breeding,
foraging, open BSW
with willows,
surrounding ponds
with aquatic
vegetation, or
providing cover next
to forage
§'
a
(33
s-
Barren-
Ground
Caribou
(Rangifer
tarandus
granti)
A, I, S (some)1'15'16: tundra and taiga habitats, the latter primarily in
winter17'18; winter range in open spruce, sometimes with lakes, ponds, and
bogs, provides sedges and arboreal and terrestrial lichens1*'20'21; Cladina
rangiferina covered 10% to 30% of the non vascular layer in three apparently
hydric and one mesic black spruce "core groups" in the western winter range
of the Denali caribou herd14"22; woodland caribou (R.. t. caribou) sometimes
select lowland black spruce habitats, including bog and muskeg, for winter
range23'24, but Canadian barren-ground caribou (R. t. groenlandicus) prefer
dry spruce-lichen forest25, a type more abundant in Canada than Alaska26'27
Forage on lichens, graminoids, and shrubs in
winter1*; terrestrial lichens often majority of
winter diet15'28"29'30; energy-rich lichens poor in
nutrients, graminoids and evergreen Equisetum
can be important and may maintain condition
during winter19'28'30'31; terrestrial lichens favored
by caribou occur in many BSW
communities14'32'33; cotton grass (Eriophorum
spp.) important spring, summer, and fall
H: foraging, open
BSW with abundant
lichens or sedges,
mainly within winter
range
19,2234,35,36
1. Manville and Young (1965)
2. Telfer (1984)
3.Franzmann(1981)
4. Coady(1982)
5. Viereck and Schandelmeier (1980)
6. Dyrnessetal. (1983)
7. Ballardetal. (1991)
8. Gasaway et al. (1985)
9. Wolff (19786)
10. Peek etal. (1976)
11. Rolley and Keith (1980 in Telfer 1984)
12. Nowak and Paradiso (1983)
13. Yarie (1983 in Viereck et al. 1992)
14. Heebner(1982)
15. Scotter(1967)
16. Miller (1982)
17. Kelsall (1968)
18. Hemming (1971)
19. Skoog (1968)
20. Durtsche and Hobgood (1990)
21. Davis etal. (1978)
22. Boertje (1981)
23. Fuller and Keith (1981)
24. Schaefer and Pruitt (1991)
25. Kelsall (1968)
26. Viereck (1983)
27. Rowe (1984)
28. Boertje (1984)
29. Duquette (1984)
30. Saperstein (1993)
31. Russell and Martell (1984)
32. Foote (1983)
33. Viereck etal. (1992)
34. White etal. (1975)
35. Bishop and Cameron (1990)
36. Cameron etal. (1992)
37. Jarrell etal. (1994)
-------
Ecologic Functions
Table 40. Mammals most characteristic of black spruce wetlands in Alaska.
Species
Common Shrew
Dusky Shrew
Red Squirrel
Northern Red-Backed Vole
Meadow Vole
Yellow-Cheeked Vole
Snowshoe Hare
Wolf
Red Fox
Lynx
Marten
Ermine
Black Bear
Comment
Use moist forest litter
Use moist forest litter
Requires drier, well-treed BSW for ample cone production
Ombrotrophic (Sphagnum) wetlands
Minerotrophic (graminoid) wetlands
Favors rhizomes for forage and moss or graminoids for burrowing
Core habitat is black spruce during winter and cyclic population lows
Wide-ranging predator uses all habitats but keys on moose and caribou
Preys on small mammals and birds
Largely dependent on snowshoe hares and follows hare cycles
Hunts in trees and on ground for voles, red squirrels, and sometimes hares
Preys on rodents and hares
Omnivorous feeder on green vegetation, fruits and berries, and moose calves
Table 41. Wood frog reproduction under ombrotrophic and minerotrophic conditions.
Site Type and
Location
Bogs and
Marshes -
Nova Scotia
Quebec
Laboratory
Pond - Quebec
Laboratory
Labratory -
Ontario
Mesocosms -
Pennsylvania
Bogs-
Minnesota
Poor Fens -
Minnesota
Fens-
Minnesota
pH
4.3 to
7.8
Low
3.4
3.0
4.0
4.2, 6.0
<4.5
4.5 to
5.0
>5.0
Life
Stage
Eggs,
larvae,
adults
Eggs
Eggs
Eggs
Eggs
Larvae
Larvae
Larvae
Larvae
Larvae
Comment
At least one life stage present
Egg mass density negatively correlated
with acidity and TOC, and hatching
success positively correlated with pH
Reduced hatching success
Some hatched
100% mortality
95% survival at 3 weeks
Increased time (8 days) to
metamorphosis at lower pH
Survival to metamorphosis near 0%
Healthy populations
Healthy populations
Source
Dale etal. (1985)
Gascon and Planas (1986)
Dale etal. (1985), Freda
and Dunson (1985:53),
Karns (1992)
Gascon and Planas (1986)
Ling etal. (1986)
Grant and Licht ( 1993)
Rowe etal. (1992)
Karns (1992)
Karns (1992)
Karns (1992)
111
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Functional Profile of Black Spruce Wetlands in Alaska
Black spruce wetlands might not provide favorable
environments for frog hibernation, although use of
dry microsites (e.g., hummocks) cannot be ruled out.
Studies reviewed for this profile suggest that areas of
standing water within BSWs, particularly those > 4.5
pH, provide breeding habitat for wood frogs. Use of
terrestrial BSW habitats for foraging by adult frogs
or for hibernation sites is poorly documented but
probable.
Functional Summary
Alaska's BSWs perform the habitat function for
a greater number of species than commonly recog-
nized. Although the characteristic and abundant
fauna of BSWs comprises relatively few species,
many more species derive at least part of their living
from these wetlands. Failure to appreciate the impor-
tance of BSW habitats may arise from the tendency
of researchers and resource managers to focus on
studies of habitat "selection" and "avoidance." Al-
though such studies provide useful information, they
sometimes draw our attention from the widespread
use of habitats that are not "preferred" (Telfer 1984).
When integrated over their substantial area within
the taiga biome, peat-forming wetlands provide sub-
stantial resources for wildlife even when not offering
preferred habitats. The importance of BSWs to
Alaska's wildlife species perhaps is not surprising
given the dominance of black spruce communities in
taiga landscapes.
The scale at which habitat is addressed deter-
mines inclusion or exclusion of open-water compo-
nents of BSWs. Most waterbirds associated with
BSWs use larger waterbodies (at a scale of, say, 102
to 103 m) having zones of mire-like vegetation rather
than small thaw ponds (at a scale of, say, 10 to 102
m), temporarily flooded areas (at a scale of, say, 1 to
10 m), or black spruce itself, although there are ex-
ceptions (e.g., green-winged teal, spring migrant wa-
terfowl, mew gulls). Waterbodies within at least
weakly minerotrophic BSWs also provide breeding
and rearing habitat for the wood frog; unflooded
BSWs probably provide foraging habitat for frogs.
Black spruce wetlands directly provide habitat to
a large number of avian species, especially passe-
rines, and a smaller number of mammalian species.
Excluding waterbirds, however, only about 12
nonraptorial bird species, 7 raptorial bird species,
and 13 mammalian species might be judged com-
monly and consistently present in BSWs. Moose and
caribou, although important users of BSWs, do not
appear in these totals because other plant communi-
ties are their preferred habitats.
Many avian and mammalian species distribute
themselves in response to composition of ground,
herbaceous, and shrub strata, which affect availabil-
ity of resources (e.g., cover and food), rather than to
overstory vegetation. One factor determining the
structure and composition of understory vegetation
of BSWs is their degree of minerotrophy. Trophic
status might prove a good predictor for presence or
absence of selected avian or mammalian species, but
such relationships rarely have been tested.
Directly sensing avian and mammalian species or
their vocalizations, nests, droppings, tracks, browsed
or cropped stems, burrows, or dens best evaluates
the habitat function of BSWs. When such observa-
tions are not possible or practical, known food or
cover preferences of various animal species provide
indicators of potential animal habitats. These indica-
tors may be identified in the field or from descrip-
tions of plant communities. Prey distribution (or the
habitat of such prey) indicates potential habitat for
avian and mammalian predators.
Functional Sensitivity to Impacts
The habitat function of BSWs is sensitive to
placement of fill. Barren fill eliminates food and
cover of potential use by vertebrates. In the unlikely
absence of continuing human activity, barren fill sur-
faces can provide sites where birds or mammals may
rest, observe the landscape for potential predators or
prey, or engage in other activities such as ingestion
of grit. Species that use fill surfaces are unlikely to
be those that originally occupied filled sites, and the
resources provided by fill surfaces are unlikely to
approach those that were lost to fill placement.
Revegetating fill surfaces might partially miti-
gate the impact of fill placement on the habitat func-
tion. Unless wetlands were created on the fill
surface, however, such revegetation would be un-
likely to provide habitat for the animal species using
the original wetland. Re-establishment of cover
structure and food density characteristic of the origi-
nal BSW would be extremely difficult and unlikely
to be compatible with the purpose for which the wet-
land was filled.
The habitat function of BSWs is less sensitive to
772
-------
Ecologic Functions
drainage than to fill placement. Drainage likely
would change composition and structure of the veg-
etation, typically increasing dominance by woody
vegetation, with concomitant changes in avian and
mammalian species occupying the site. In the ab-
sence of other disturbance, however, the habitat re-
sources provided by the drained site should
approximate in magnitude, if not in kind, those
present before drainage.
The impacts of mire drainage on the habitat func-
tion would be difficult to mitigate if the objective
were to restore pre-drainage avian and mammalian
habitats. Habitat manipulation, for instance pre-
scribed fire to prevent invasion of a drained fen by
trees, might minimize changes in plant species com-
position. Although unlikely to be compatible with
the purposes for which mires are drained, ponds ex-
cavated to, or below, the water table could replace
portions of specific (e.g., waterfowl) habitats lost
with drainage.
DATA GAPS
Data gaps exist with respect to the ecologic func-
tions of Alaska's BSWs. Additional studies of nutri-
ent cycling and export, food chain support, and habi-
tat are warranted. The following discussion identifies
information needs for these functions of BSWs.
Nutrient Cycling
Studies of taiga forest ecosystems have yielded a
significant amount of information on nutrient cy-
cling in black spruce forest, including cold, wet
stands occurring on permafrost soils. These studies
address only a portion of the ecologic communities
that lie on a gradient from treed to treeless wetlands,
however. Nutrient cycling in black spruce communi-
ties characterized as "woodland" and "dwarf tree
scrub" by Viereck et al. (1992:24-25) apparently has
received little study in Alaska, although some data
have been collected in sparsely treed, Sphagnum-
dominated stands (e.g., Heilman 1966, 1967;
Dyrness and Grigal 1979). Although one can infer
more rapid nutrient cycling in minerotrophic than in
ombrotrophic BSWs, comparative studies on the
trophic controls of nutrient cycling in these commu-
nities are lacking.
Nutrient Export
The magnitude of nutrient export from BSWs in
Alaska and its importance to aquatic systems have
received little study. Black spruce wetlands export C,
which may support detrital food chains and allow
significant production by higher trophic levels in
taiga waterbodies, but virtually no studies exist to
explore these potential relationships. In addition, C
may affect thermal characteristics of brownwater
systems so that they offer favorable thermal environ-
ments for fish, a problem currently under investiga-
tion (J. D. LaPerriere, Alaska Coop. Fish Wildl. Res.
Unit, pers. commun.). The role of exported C in
brownwater systems demands attention because fish
species are highly-valued resources for Alaska resi-
dents.
Black spruce wetlands presumably export small
amounts of N and P, based on studies elsewhere, but
such exports should be quantified for Alaska. Export
of P from BSWs, although likely to be small, might
control production in some taiga waterbodies be-
cause P availability often limits primary production
in oligotrophic lakes (Wetzel 1983:286) and tundra
ponds (Hobbie 1984:10-22). Nitrogen can be a lim-
iting factor for primary production in aquatic sys-
tems where P and C are available in excess of
demand (Wetzel 1983:251), but excess P is unlikely
in ombrotrophic waterbodies.
Food Chain Support
Significant information on primary production
(and thus biomass available for food-chain support)
exists for black spruce forests, including cold, wet
stands on permafrost soils. Much less is known
about primary production in sparsely treed,
palustrine scrub-shrub wetlands. Partitioning of en-
ergy flows between grazing and detrital food chains
in BSWs, the effects of trophic status on such parti-
tioning, and the vertebrate biomasses supported by
energy flows have received little study. Black spruce
wetlands generally produce less biomass than do
warm, well-drained taiga ecosystems, but most taiga
vertebrates at least occasionally use black spruce
habitats. The food-chain support function of BSWs
thus is important to Alaska's fish and wildlife popu-
lations.
Habitat
Habitat studies of Alaska birds and mammals
often have been autecologic rather than synecologic,
at least with respect to wildlife use of BSWs. These
113
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Functional Profile of Black Spruce Wetlands in Alaska
studies rarely, if eyer, are framed to reveal the rela-
tionships between wildlife species and wetland
classes such as bogs or fens. As a result, identifying
the habitat functions of BSWs is difficult without
species-by-species review of the literature. Further,
even autecologic information on birds and nongame
mammals of taiga regions is sparse. Soricids and
microtines provide examples of taxa for which the
literature sometimes gives habitat preferences in
only the most general terms. Synecologic studies of
vertebrate use of BSWs, particularly studies that dif-
ferentiate between ombrotrophic and minerotrophic
wetlands, as well as vegetation structure and compo-
sition, would be most helpful in fully documenting
their habitat function.
Functional Sensitivity to Impacts
The sensitivity of nutrient cycling in BSWs to
placement of fill seems self-evident (i.e., elimination
of cycling) and should require no study. In contrast,
the effects of wetland drainage on this function are
not clear. The magnitude of nutrient cycling follow-
ing wetland drainage depends on the balance be-
tween production and decomposition. Factors
including increased aeration and decomposition of
organic soils, altered soil temperature regimes, in-
creased ombrotrophy of surface layers, shifts in spe-
cies composition, and changes in permafrost tables
likely influence outcomes. Accurate predictions
about the effect of drainage on nutrient cycling re-
quire experimental investigations of the controls on
production and decomposition under drained and
undrained conditions for both ombrotrophic and
minerotrophic BSWs.
Data gaps exist with respect to the impacts of fill
placement on nutrient exports from BSWs. Presum-
ably export of C ceases with fill placement. The
same is unlikely to be true of N and P if anthropo-
genic sources are present. Because the natural nutri-
ent-export function of BSWs for N and P is poorly
quantified, the effects of fill placement on this func-
tion are basically unknown. Several studies have
shown small effects of mire drainage on nutrient
export in the form of elevated DOC (Bourbonniere
1987), N (Clausen and Brooks 1983a), and P (Moore
1987), but similar information is not available for
BSWs in Alaska.
Barren fill provides no food-chain support, a self-
evident impact that requires no study. In contrast,
drainage does not eliminate the food-chain support
function of BSWs, and the effects of such drainage
are not easily predicted. Data gaps exist regarding
the evolution of drained sites, particularly
minerotrophic BSWs, under the potentially opposing
effects of increased mineralization of nutrients and
development of more ombrotrophic vegetation with
lowered water tables. Studies should address com-
munity composition and production and partitioning
of energy flow between grazing and detrital food
chains before and after drainage.
The sensitivity of the habitat function of BSWs to
barren fill is self-evident, but for fill surfaces sup-
porting re-established vegetation, there is room for
research on how such vegetation can be made to pro-
vide productive wildlife habitat. Research might tar-
get structure and composition of vegetation in
relation to species-specific preferences of wildlife,
including management techniques for achieving de-
sired endpoints. The effect of drainage on the habi-
tat function of BSWs is not clear. Potential changes
in plant species composition as sites become drier
but, perhaps, more ombrotrophic, require study. Re-
search on the evolution of drained (but otherwise un-
altered) BSWs in relation to wildlife habitat could
facilitate prediction of drainage impacts on the habi-
tat function.
114
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SOCIOECONOMIC USES
Sather and Smith (1984:58-68) divide socioeco-
nomic uses of wetlands into consumptive and
nonconsumptive components. Consumptive uses
include harvest of wetland resources whereas
nonconsumptive uses include recreation and aes-
thetic or cultural appreciation. Adamus and
Stockwell (1983:46-47) further divide recreation
into active and passive components.
CONSUMPTIVE
Wetlands provide resources of use to humans, ei-
ther as individuals or collectively. Consumptive uses
of these resources thus may take place at a personal
or societal level. Subsistence and personal uses of
wetland resources include harvests of fuel, food, and
other plant and animal materials largely for direct
consumption, distribution, or barter. Extraction of
economic resources includes logging, mining, fish-
ing, trapping, and guiding for cash sale.
Subsistence and Personal Uses
Subsistence and personal uses offish and wildlife
resources, plants, and fuels from wetlands are
closely related to extraction of economic resources
but are not pursued in a commercial or recreational
context. Alaska Natives are highly dependent upon
wetlands for provision of subsistence resources
(Ellanna and Wheeler 1989) to support noncash
economies. Wild foods supply up to 80% of intake in
some native communities in Alaska and Canada
(Larson 1991). In interior Alaska, for example, the
village of Minto has an annual per capita harvest of
more than 450 kg of wild foods (Anonymous 1989).
Other Alaska residents harvest wild materials for
personal consumption as well: the statewide median
harvest is -113 kg (Anonymous 1989). Black spruce
wetlands provide wild resources needed for subsis-
tence and personal uses.
Harvest of animals for subsistence and personal
use includes large game, small game, furbearers, wa-
terfowl, and fish (Table 42). With the exception of
fish, harvested species directly use BSWs. Even
some fish species that enter subsistence harvests
may be influenced by BSWs. Coho salmon, for ex-
ample, rear in areas of groundwater discharge with
emergent or shrub vegetation during the freshwater
phase of their life cycle (A. G. Ott, Alaska Dep. Fish
Game, pers. commun.). Such areas presumably are
spring fens. Likewise, forage fish that help support
populations of harvested species such as northern
pike and burbot (Lota lota) inhabit brownwater
drainages that receive water from BSWs along the
Tanana River (A. G. Ott, Alaska Dep. Fish Game,
pers. commun.).
Residents of communities in the upper Tanana
Valley of interior Alaska take moose, caribou, and
smaller numbers of black and brown bears (Marcotte
1991:59-61). Small game and waterfowl species
harvested in this area include snowshoe hare; ruffed,
sharp-tailed, and spruce grouse; willow ptarmigan;
numerous duck species; several goose species; and
sandhill crane (Marcotte 1991:60,63). Finally, red
squirrel, muskrat, beaver, least weasel, marten,
mink, otter, wolverine, wolf, red fox, and lynx are
furbearers taken in the Interior (Andrews 1988: 210-
240, Marcotte 1991:62). The importance of fur-
bearer harvest is illustrated by Minto where 49% of
the households had a member who trapped in 1983-
84 (Andrews 1988:218).
Plant materials potentially harvested in BSWs in-
775
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Functional Profile of Black Spruce Wetlands in Alaska
elude wood, craft materials such as bark or roots, and
berries (Andrews 1988:241-260, Marcotte 1991:64-
65). Wood may be used as fuel or construction ma-
terial (Andrews 1988:251-255). Pole-size spruce
find many uses in construction (e.g., fish drying
racks) in rural communities (Andrews 1988:254-
255). Pole-size and slightly larger spruce fuelwood
grow in well-treed BSWs in Alaska and may be har-
vested for personal use. Five upper Tanana commu-
nities had an estimated combined harvest of 8,184
cords of wood (Marcotte 1991:71).
Other subsistence uses of wood include basketry
incorporating birch bark and spruce roots (Marcotte
1991:65). Harvest of spruce roots takes place "in
mossy ground close to river or lake banks where the
ground is moist" (Nelson et al. 1982), a description
consistent with BSWs; paper birch occasionally oc-
curs in these communities as well. Berries provide
an important wild harvest for subsistence and per-
sonal use by Alaskans (Table 42).
Extraction of Economic Resources
Humans extract many economic resources from
wetlands: timber (Mitsch and Gosselink 1986:397),
peat (Maltby 1991), fish, shellfish (Maltby 1986:19-
24), and furbearers (Mitsch and Gosselink
1986:394). Economic values have been estimated
for wetlands supplying these resources, but many
criticisms of these techniques exist in the literature
(Sather and Smith 1984:61-62) because wetlands
have global life support values (e.g., biogeochemical
cycling of elements) independent of economic re-
source extraction (Maltby 1986:146, Mitsch and
Gosselink 1986:405-408). Economists have recently
developed novel methods to apply economics to eco-
systems (Maxwell and Costanza 1989).
Commercial use of renewable resources directly
or indirectly related to BSWs in Alaska includes
wood harvest, trapping furbearers, commercial fish-
ing, and guiding sport hunters and fishers. Silver-
sides (1983) has proposed harvest of northern boreal
forests for energy feedstocks. Black spruce wetlands
could provide such feedstocks because all cellulosic
material can be used, regardless of tree size or spe-
cies, but low biomass production in Alaska BSWs
would make them the last choice for harvest. At
present, little or no commercial harvest of black
spruce occurs in interior Alaska, although some
pole-sized material has been salvaged from burned
stands for fence posts, furniture manufacture, and
similar uses. Van Hees (1990) listed "the dispersed
nature of the resource, poor access, and lack of mar-
kets" as limiting use of forested wetlands in Alaska.
Commercial trapping largely overlaps trapping
for subsistence and personal uses, since trapping can
be a source of cash income in subsistence econo-
mies. Harvest levels for furbearers fluctuate drasti-
cally with fur prices (T. Boudreau, Alaska Dep. Fish
Game, pers. commun.); thus, short periods of record
(Table 43) may underrepresent sustainable harvest
levels. Trapping in the Interior harvests furbearers
produced in BSWs.
Commercial fishing, as a component of the sea-
food industry, the state's largest private employer
(Holmes 1990), is extremely important to Alaska's
economy. Alaska's salmon harvests had ex-vessel
Table 42. Representative subsistence harvests for several interior Alaska resources directly or indirectly
related to black spruce wetlands.
Resource
Moose
Ducks and geese
Fish
Fish
Berries
Per Capita
Harvest
(kg)
17 to 92
-11
-41
567
>3
Location
Several representative interior Alaska
villages
Minto
Upper Tanana communities
Hughes
Dot Lake, Tanacross, Minto
Source
Andrews (1988:272), Marcotte
(1991:74-82)
Andrews (1988:184-194,267)
Marcotte (199 1:70)
Andrews (1988:271)
Andrews (1988:267), Marcotte
(1991:75-77)
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Socioeconomic Uses
Table 43. Mean annual estimated furbearer harvests between 1986 and 1991 in Game Management Unit
(GMU) 25 (northeastern Interior), GMU24 (Koyukuk River), andGMU21 (mid-Yukon River) (Abbott 1993:
250-253,277-283,291-294).
Species
Red Fox
Lynx
Mink
Muskrat
Otter
Wolverine
Beaver
Marten
Harvest (number)
GMU 25
233
569
87
836
5
48
314
3,739
GMU 24
41
106
68
16
13
48
467
1,760
GMU 21
63
38
108
34
44
25
1,059
2,781
values of $478 million, $754 million, and $505 mil-
lion in 1987, 1988, and 1989, respectively (Savikko
and Page 1990:40). In 1989, commercial fishers har-
vested -833,000 coho salmon from the Yukon,
Kuskokwim, and Copper rivers, which drain the
taiga landscapes of interior Alaska (Savikko and
Page 1990:33-36). To the extent (perhaps limited)
that rearing echoes use drainages arising in
minerotrophic BSWs, commercial fishing represents
economic resource extraction of wetland-dependent
resources.
Guided hunts for big game and waterfowl and
guided fishing contribute to the economy of taiga
regions. Big game species using BSWs and targeted
by guided hunters include black and brown bears,
moose, and caribou. To the extent that hunted popu-
lations of big game and waterfowl depend upon
wetland habitats, revenues from guiding represent
extraction of economic resources from wetlands.
Guided fishing is analogous to guided big game
hunting and commercial fishing in the sense that
populations of targeted species such as coho salmon
or northern pike may rear in habitats associated with
BSWs. Quantitative information on the proportion
of guiding revenues that can be attributed to the ex-
traction of wetland-dependent resources does not
exist.
Commercial extraction of nonrenewable re-
sources also occurs in BSWs. Most prominent is
mining of peat for fuel and horticultural uses, but
materials such as gravel and placer and hard rock
minerals may be mined from underlying strata as
well. Some might consider peat a renewable re-
source because organic matter can continue to accu-
mulate if wetland conditions are re-established
following mining, but thousands of years would be
required for reaccumulation of commercial quanti-
ties of peat. Thus, peat is not renewable in periods
amenable to human economic or resource planning.
Small-scale peat mining for fuel has occurred in
northern Minnesota mires; more recent large-scale
proposals have proven infeasible (Glaser 1987:67-
68). Alaska's peat resources have been mapped
based on the distribution of Histosols and an as-
sumed peat depth of 1.5 m (Rawlinson and Hardy
1982). Huck and Rawlinson (1982) provide more
detailed information for southcentral Alaska. Avail-
able energy from Alaska's fuel-grade peat is esti-
mated to range from 6.9 to 77.5 quads under various
assumptions (e.g., including or excluding frozen
peat, ability to reduce ash content) (Rawlinson and
Hardy 1982). Significant use of peat for fuel pres-
ently does not occur in Alaska, but horticultural peat
is mined in or near Alaska's larger population cen-
ters. Peat extracts have been proposed as a fermen-
tation substrate for submerged culture of edible
mushrooms (Martin 1983), but such use is not
known to have occurred in Alaska.
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Functional Profile of Black Spruce Wetlands in Alaska
Black spruce wetlands located in floodplains can
be a source of alluvial gravel following removal of
overlying peat deposits; such gravel pits operate in
the Fairbanks area of interior Alaska. In addition,
many of Alaska's placer gold mines operate in val-
ley-bottom BSWs. Miners strip peat and mineral soil
overburden from underlying gold-bearing alluvial
materials. Likewise, Glaser (1987:69-70) describes
an ore-bearing greenstone formation occurring under
peat and glacial till in northern Minnesota. Hardrock
gold ores underlying BSWs currently are being de-
veloped for mining near Fairbanks as well. In these
cases, extraction of nonrenewable economic re-
sources from BSWs is only coincidental.
Use Summary
Black spruce wetlands provide for consumptive
uses. Subsistence, personal, and commercial har-
vests of wetland-dependent fish, wildlife, and plant
resources are the most important consumptive uses
of Alaska's BSWs. Such uses predominate through-
out the Subarctic (Larson 1991). Consumptive uses
of renewable wetland resources may become more
important as improved technologies and favorable
market conditions develop for biomass conversion
and manufacture of wood fiber products. Consump-
tive uses of nonrenewable resources such as peat,
gravel, and placer and hardrock minerals occurring
in or beneath BSWs currently are few in Alaska.
The magnitude of consumptive uses of BSWs
perhaps is best judged through regional and local so-
cioeconomic studies, including surveys and records
of animal, plant, and peat harvests. Less direct meth-
ods include documenting occurrence of BSWs
within traditional harvest areas for communities,
within registered guiding areas targeting wetland-
dependent species, or along established traplines.
Black spruce wetlands that provide habitats for fish
and wildlife species included in subsistence, per-
sonal use, and commercial harvests may be assumed
to support potential consumptive use. The magnitude
of consumptive uses of nonrenewable resources oc-
curring within or beneath BSWs probably can be
judged from the records of management or regula-
tory agencies because such resource extraction nor-
mally occurs with government oversight.
Use Sensitivity to Impacts
Consumptive use of wetland-dependent renew-
able resources is sensitive to placement of fill, as dis-
cussed with respect to the food-chain support and
habitat functions. Harvests of wetland-dependent
fish, wildlife, peat, and plant resources potentially
are diminished in proportion to wetland area filled.
Placement of fill does not necessarily prevent extrac-
tion of nonrenewable resources such as peat or min-
erals at some future time, but fill removal would
render mining more difficult and expensive.
Re-establishment of vegetation on fill surfaces,
although unlikely to be compatible with the purposes
for which fills are placed, could provide habitat for
nonwetland animal species subject to subsistence,
personal, and commercial uses. Harvest of such al-
ternative species might mitigate loss of renewable
BSW resources. Fully mitigating the effects of fill
placement on extraction of nonrenewable resources
does not appear feasible, but minimization of fill
depths would reduce costs of future fill removal for
mining underlying peat or mineral resources.
Consumptive use of renewable resources found
in BSWs may be facilitated or hindered by drainage.
Drainage can increase timber production (e.g., Dang
and Lieffers 1989). In contrast, draining
minerotrophic wetlands used by rearing coho salmon
could decrease harvest of adult fish. Similar adverse
effects might be expected on harvests of other wet-
land-dependent fish and wildlife species. Black
spruce wetlands generally must be drained to extract
nonrenewable resources such as peat or underlying
minerals and thus drainage can be considered to ben-
efit the consumptive use.
Habitat manipulation designed to maintain popu-
lations of fish and wildlife species dependent upon
BSWs might mitigate adverse effects of drainage on
consumptive use of those populations. Alternatively,
species adapted to mesic conditions might provide
substitute harvests for subsistence, personal, and
commercial uses. Presumably, no mitigation would
be required for the generally positive effects of
drainage on extraction of fuel, fiber, and minerals
from mires.
NONCONSUMPTIVE
Socioeconomic uses of BSWs that do not involve
harvest of plants or animals for consumption or sale,
and that do not involve extraction of peat, minerals,
or other nonrenewable resources, are non-consump-
tive. As has been pointed out many times by others,
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Socioeconomic Uses
"nonconsumptive" uses of natural resources are
rarely without impact; nevertheless, the term conve-
niently discriminates between those activities that
intentionally remove materials from natural systems
and those that do not. Nonconsumptive uses of wet-
lands include active and passive recreation, nature
education, appreciation of unique geomorphic fea-
tures, and preservation of scarce species. Documen-
tation and evaluation of such nonconsumptive uses
of wetlands is, in many cases, neither rigorous nor
extensive (Sather and Smith 1984:60).
Active Recreation
Active recreation in wetlands includes swimming
and boating (Adamus and Stockwell 1983:46). Hik-
ing, mountain biking, skiing, dog sledding,
snowmobiling, and similar activities might be added
for Alaska's BSWs, which often are more accessible
in winter than in summer. Active recreation can be
divided into motorized and unmotorized activities.
Motorized forms of active recreation in BSWs in-
volve snowmobiles, all-terrain vehicles (ATVs), and
airboats (Table 44). Nonmotorized active recreation
in BSWs includes hiking, mountain biking, horse-
back riding, nordic skiing, and dog sledding (Table
45).
Passive Recreation and Use of Heritage Sites
Some socioeconomic uses of wetlands, labeled as
passive recreation and use of heritage sites, occur
Table 44. Motorized forms of active recreation that occur in black spruce wetlands (BSWs) in Alaska.
Activity
Snowmobiles
All-terrain
vehicles
Airboats
Season
Winter
Summer,
some winter
use on trail
systems
Summer
Comment
Snowmobiles can access most components of the taiga landscape, limited
only by dense tree cover, deep snow without trails, or open water; cleared
trails, including traplines, allow snowmobiles to use even densely treed
wetlands
Provide motorized access to backcountry areas on established trails or
cross-country routes that often pass through BSWs, although wettest areas
avoided; traffic can degrade permafrost and create the potential for erosion
in subarctic wetlands (Racine and Ahlstrand 1991)
Traverse sparsely treed BSWs and treeless fens (Racine and Walters 1991)
on the Tanana Flats
Table 45. Nonmotorized forms of active recreation that occur in black spruce wetlands (BSWs) in Alaska.
Activity
Hiking
Mountain
biking
Horseback
riding
Nordic skiing
Dog sledding
Season
Summer,
some winter
use of trails
Summer,
some winter
use of trails
Summer,
some winter
use of trails
Winter
Winter
Comment
Minimize summer use of trails passing through the wettest wetlands
because travel can be difficult or uncomfortable; in winter, trails passing
through BSWs are used
Minimize summer use of trails passing through the wettest wetlands
because travel can be difficult or uncomfortable; in winter, trails passing
through BSWs are used
Minimize summer use of trails passing through the wettest wetlands
because travel can be difficult or uncomfortable; in winter, trails passing
through BSWs are used
Nordic skiers often use dedicated ski trails that pass through BSWs as well
as using the general trail system used by mushers and snowmobilers
Major winter use of most trails; some trails major training routes for
competitive mushers, others routes for recreational travel and winter
camping; many trails on valley bottoms or flats in BSWs to avoid steep
terrain (pers. observ.)
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Functional Profile of Black Spruce Wetlands in Alaska
without obvious consumption of wild resources and
sometimes without actual entry into the wetlands
themselves. Adamus and Stockwell (1983:47) de-
scribe passive recreation and uses of heritage sites as
"aesthetic enjoyment, nature study, picnicking, edu-
cation, scientific research, open space, preservation
of rare or endemic species, maintenance of the gene
pool, protection of archaeologically or geologically
unique features, maintenance of historic sites, and an
infinite number of other mostly intangible uses."
Black spruce wetlands support many of these uses.
Passive recreation encompasses aesthetic enjoy-
ment and open space uses of BSWs. Wetlands occur-
ring in a wilderness setting contribute to landscape
diversity and presumably contribute to the aesthetic
enjoyment of such landscapes. Although use of
mires for open space at least conceptually occurs in
wilderness contexts, such use is most apparent in
urban and suburban settings where open space is
scarce. Many of the remaining open areas in Anchor-
age and Fairbanks, for example, are BSWs (Munici-
pality of Anchorage 1982; Hogan and Tande 1983;
D.K. Swanson, Nat. Resour. Conserv. Serv., pers.
commun.).
Although passivity may characterize a few uses
of heritage sites, most uses listed by Adamus and
Stockwell (1983:47), such as nature study and edu-
cation, imply some sort of active involvement with
wetlands. Black spruce wetlands relatively acces-
sible from roads and trails not only provide open
space but also the opportunity for bird watching and
nature study, especially if ponds supporting breeding
waterfowl and other birds (e.g., Hogan and Tande
1983, Murphy et al. 1984, Martin et al. 1995) occur
in association with the wetland. On a more organized
basis, BSWs can be sites for nature education, such
as occurs on the Creamer's Field Migratory Wildlife
Refuge in Fairbanks, and sites for scientific research
(e.g., Slack et al. 1980, Siegel and Glaser 1987).
Mire "types" and plant communities sometimes
are rare or endangered because of changes brought
about by wetland drainage or loss (Lee et al. 1982,
Eurola et al. 1991). Minnesota mires support rare
plant species (Glaser 1987:42-45), and brownwater
streams draining Alberta peatlands contain rare
midges (Boerger 1981). In Alaska, BSWs support a
number of relatively rare plant species (R. Lipkin,
Alaska Nat. Heritage Prog., Univ. Alaska, Anchor-
age, pers. commun.). Protecting habitats, and conse-
quently gene pools, for rare, threatened, or endan-
gered species constitutes a use of heritage sites.
Black spruce wetlands in the zone of discontinu-
ous permafrost sometimes contain unique geomor-
phic features such as thermokarst ponds and palsas.
Like preserving rare plants and animals, preserving
unusual geomorphic features is a use of heritage
sites. These features can serve educational and re-
search purposes as well.
Use Summary
Black spruce wetlands provide for non-consump-
tive uses. Active recreation in BSWs, particularly in
winter, appears to constitute their major
nonconsumptive use. Dog sledding and
snowmobiling predominate, but hiking, mountain
biking, horseback riding, nordic skiing, ATV riding,
and airboating also occur in BSWs. Less active uses
of these wetlands include their provision of open
space and landscape diversity, sites for nature study
and education, research sites, habitats and mainte-
nance of gene pools for rare species, and unique geo-
morphic features related to permafrost phenomena.
Nonconsumptive uses of BSWs are best docu-
mented through local and regional surveys, studies,
or plans related to outdoor recreation, heritage sites,
and land use. The current magnitude of many
nonconsumptive uses of wetlands depends upon
their accessibility and proximity to population cen-
ters. For example, established trails through or adja-
cent to BSWs may indicate their potential for
recreational and educational use. Other wetland uses,
such as maintaining gene pools of rare species, wil-
derness, and landscape diversity, may be inversely
related to proximity of human populations. The na-
ture of surrounding landscapes and their ecosystems
or the uniqueness of BSWs within such landscapes
may indicate these uses.
Use Sensitivity to Impacts
The sensitivities of nonconsumptive uses of
BSWs vary with respect to fill. Active recreation that
incidentally occurs in wetlands (e.g., use of a trail
that passes through a bog) often would not be af-
fected by fill. In fact, fill sometimes is placed in
wetlands to facilitate such recreation (e.g., construc-
tion of bike paths). Fill placement would adversely
affect use of BSWs by airboats. All uses of BSWs
that depend upon the wetland community itself are
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Socioeconomic Uses
sensitive to fill placement. Examples include wilder-
ness, study of wetland environments, protection of
rare species, and provision of landscape diversity (at
least where BSWs are not abundant).
Re-establishment of diverse natural communities
on fill surfaces, although likely not compatible with
the purposes for which fills are placed, could miti-
gate some adverse impacts. Bird watching, for ex-
ample, could occur in shrub thickets on fill surfaces,
and revegetated fills would provide open space.
Mitigating fill impacts on rare mire species appears
infeasible without carefully replicating lost habitats.
The nonconsumptive uses of BSWs also vary
with respect to their sensitivity to drainage, but
drainage impacts probably are less severe than those
associated with fill. Wetland drainage might facili-
tate most forms of active recreation, particularly
summer use of formerly wet trails. In contrast, drain-
age likely would prevent airboats from using
sparsely treed BSWs. Wetland drainage would alter
vegetation communities with concomitant effects on
passive recreation and use of heritage sites. Although
open space uses and nature study could continue,
species associations would differ. Impacts of drain-
age on protection of rare species, particularly hydro-
phytic plants, likely would be severe, although less
than those imposed by fill. Unique geomorphic fea-
tures resulting from permafrost phenomena might be
lost under altered thermal and hydrologic regimes
following drainage.
Most adverse impacts of drainage on non-con-
sumptive uses of BSWs would be difficult to miti-
gate and would require different techniques for
different uses. Drainage systems that were suffi-
ciently wide to accommodate airboats might allow
continued airboat use but could impair trail use by
hikers, snowmobilers, dog sledders, and skiers un-
less mitigated by placement of culverts or bridges.
Habitat manipulation, such as prescribed burning to
control woody vegetation, might mitigate the im-
pacts of wetland drainage on some rare species but
is unlikely to meet the needs of obligate wetland
plants. Mitigating drainage impacts on unique geo-
morphic features of mires does not appear economi-
cally feasible.
DATA GAPS
Few studies directly address socioeconomic uses
of BSWs. The existence and magnitude of these uses
must be inferred from indirect data. The strength of
such inferences often is limited by lack of quantita-
tive harvest records, use of both wetland and
nonwetland habitats by target species, and confound-
ing effects of varying market forces on harvests.
Perhaps even less information is available for
nonconsumptive uses of wetlands. The following
discussion identifies data gaps with respect to socio-
economic uses of BSWs.
Consumptive Uses
Indirect data sources for consumptive uses of
BSWs sometimes are available in socioeconomic
studies of individual communities or regions,
records of fish and wildlife harvests, and economic
records of commercial activities. Although these
sources provide harvest levels for subsistence, per-
sonal, and commercial uses of fish and wildlife, they
do not partition harvests by habitat or wetland class.
A general lack of information relating fish and wild-
life habitat use to specific wetland classes exacer-
bates this problem. In ecological terms, flows of
energy and biomass from BSWs to humans and hu-
man uses have not been quantified. Synecological
studies of BSWs could help fill these data gaps.
Records of resource management and regulatory
agencies, if comprehensively examined, might docu-
ment consumptive uses of BSWs that involve peat
mining or mineral extraction. No single repository of
such information exists, however, and past and cur-
rent mining does not address the potential for future
mining in or beneath wetlands. Efforts to inventory
the peat resources of Alaska by even minimal sam-
pling of peat depths and characteristics have been
limited to relatively small areas (e.g., Huck and
Rawlinson 1982, Rawlinson 1986). State and federal
agencies map Alaska's mineral resources, but corre-
lating these resources with BSWs would require
detailed wetland mapping. Further geologic and eco-
nomic studies of peat and mineral resources in rela-
tion to BSWs would help document their existing
and potential uses for extraction of economic re-
sources.
Nonconsumptive Uses
Some nonconsumptive uses of BSWs in or near
human population centers can be inferred from land
management plans, establishment of parks and rec-
reation areas that include such wetlands, and pres-
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Functional Profile of Black Spruce Wetlands in Alaska
ence of established trail systems, but quantitative
data on use of specific wetland types does not appear
to exist. This problem is complicated by the wide va-
riety of nonconsumptive uses, some of which do not
require entry into individual wetlands in order to be
fulfilled (e.g., aesthetic appreciation) and are poorly
amenable to measurement. Virtually no direct data
are available for nonconsumptive uses of BSWs
away from human population centers. Scientifically
designed survey strategies, supplemented by quanti-
tative observations of actual wetland use, might of-
fer a way to elicit information from the populace on
their nonconsumptive uses of BSWs.
Use Sensitivity to Impacts
The impacts of filling or draining BSWs on their
consumptive and nonconsumptive uses can be in-
ferred but are poorly documented. Reduction in the
renewable-resource base through placement of fill
concomitantly reduces consumptive uses of plants
and animals. Better understanding of the habitat
function and consumptive uses of BSWs would help
define potential impacts of wetland fill. Research
quantifying declining subsistence and personal uses
of wild materials in areas of high wetland loss from
fill would be helpful, but confounding variables such
as shifts in lifestyle from rural to urban might make
the research difficult.
The impacts of fill on consumptive uses of non-
renewable resources such as peat or underlying min-
erals qualitatively appear self-evident. Economic
studies of the costs of removing fill to reach under-
lying resources could provide quantitative documen-
tation of the disincentives to mining imposed by fill
placement. Other factors such as property values and
land use of filled terrain might provide even stronger
disincentives for extraction of peat or mineral re-
sources underlying fill.
Drainage of BSWs without conversion to agricul-
ture or placement of fill is uncommon in Alaska,
which limits opportunities for direct studies of drain-
age impacts on consumptive uses. Nevertheless,
studies better documenting the habitat function of
BSWs, including their effects on waterbodies and
fisheries resources occurring in wetland contexts,
would strengthen predictions concerning drainage
impacts on wetland-dependent animal species. In a
related vein, studies documenting the relationships
between distributions of wetland plants and
hydroperiods would strengthen predictions concern-
ing changes in plant communities with drainage,
which could then be linked to potential changes in
consumptive use of renewable wetland resources.
Long-term observations of experimentally drained
BSWs might provide a similar basis for predicting
potential changes in consumptive use. The salutary
effects of drainage on extraction of nonrenewable
resources appears self-evident and does not require
study.
The impacts of filling or draining BSWs on their
nonconsumptive uses are undocumented. Some ben-
eficial (e.g., fill for trail construction) and adverse
(e.g., loss of wetland study areas) effects are self-
evident. The primary gap is lack of data on
nonconsumptive uses themselves. Filling this gap
would strengthen inferences about the impacts of
filling or draining BSWs on their nonconsumptive
uses. Experimental verification of predicted changes
in wetland communities following drainage is lack-
ing for Alaska, although such changes have been
documented elsewhere (e.g., Glaser 1987:67). Previ-
ously discussed data gaps concerning habitat and
food chain-support functions of BSWs also are rel-
evant to changes in nonconsumptive use following
drainage.
722
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SUMMARY AND CONCLUSIONS
Alaska's 70.7 million ha of wetlands include
about 14 million ha of black spruce wetlands
(BSWs), which are important boreal ecosystems. For
purposes of this report, BSWs are wetlands support-
ing black spruce of any size or stand density. Regu-
latory decisions concerning conversion of these
wetlands to other uses require knowledge of their
wetland functions and hence their values to society.
The objective of this report is to provide a "func-
tional profile" of Alaska's BSWs for use by scien-
tists, wetland managers, commercial interests, and
citizens and to facilitate implementation of the
hydrogeomorphic method of wetland classification.
This profile cites many studies conducted outside
Alaska, usually from boreal forest. Future research
should verify extrapolation of cited literature to
Alaska's BSWs.
BLACK SPRUCE AND
THE TAIGA ENVIRONMENT
Black spruce wetlands occur with the taiga, the
northern coniferous forest extending across North
America and Eurasia. Taiga occurs under continen-
tal climates characterized by extreme temperatures,
low precipitation, relatively low rates of evapotrans-
piration, and large seasonal variation in solar radia-
tion. Vegetation and topography strongly control the
amount of solar radiation reaching ground surfaces.
Soils of subarctic sites receiving reduced solar radia-
tion or insulated by thick moss cover can remain fro-
zen at depth for periods of >2 yr and thus are
permafrost. Permafrost distribution in subarctic
taiga is discontinuous.
Unique geomorphic features associated with per-
mafrost include peat plateaus, patterned ground in-
duced by ice wedges, and ice-cored hummocks
called palsas. Fire or other disturbance often alters
thermal regimes of permafrost sites and increases
seasonal depths of thaw. Where ice contents of per-
mafrost soils are high, thaw can create irregular
thermokarst topography and thaw lakes or ponds.
The relative impermeability of permafrost contrib-
utes to wetland formation; thus, frost and thaw phe-
nomena in part account for interior Alaska's mosaic
of wetlands and nonwetlands.
Pleistocene glaciation, although limited in extent
in Alaska, influenced development of present-day
taiga ecosystems. In interior Alaska, shrub tundra re-
placed the Mammoth Steppe of the Pleistocene
-14,000 yr BP, followed after -10,000 yr BP by for-
ests containing white spruce, paper birch, resin
birch, juniper, and American green alder. Black
spruce became abundant after 7,000 yr BP, and spe-
cies composition has remained essentially un-
changed since that time.
Within North American taiga, tree size and
canopy cover in increase southerly fromforest-tun-
dra to open woodland, main boreal forest, and bo-
real-mixed forest ecotone. Alaska's taiga primarily
comprises open woodland and forest of black and
white spruce, tamarack, paper birch, quaking aspen,
and balsam poplar. Typical community types of
black spruce include Picea mariana/Vaccinium
uliginosum.-Led.um groenlandicum/Pleurozium
schreberi, Picea manana/feathermoss-lichen, and
Picea mariana/Sphagnum spp.-Cladina spp.
Fire, at natural return intervals of 100 to 200 yr,
and fluvial processes periodically reset taiga succes-
sion and create a mosaic of plant communities. The
semiserotinous cones of black spruce increase seed
release following fire. Black spruce/feathermoss
succession has six generalized stages: newly burned,
723
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Functional Profile of Black Spruce Wetlands in Alaska
moss-herb, tall shrub-sapling, dense tree, hardwood,
and spruce. Post-fire succession in black spruce of-
ten produces little change in species composition of
vascular plants. Wet black spruce sites in lowlands
may cycle between treeless wetlands and BSWs.
Erosion in floodplains removes older plant com-
munities, and deposition forms new surfaces for pri-
mary succession. These sites succeed to white
spruce. Thick moss layers and canopy closure in late
successional stages lower soil temperature, cause
permafrost aggradation, and increase soil moisture.
Black spruce may replace white spruce as soils be-
come waterlogged in old floodplain stands protected
from fire.
Black spruce occurs across boreal North
America, largely coincident with the taiga, and cov-
ers 44% of interior Alaska. This species commonly
grows in the Interior on cold, wet sites at elevations
of <610 m, where it typically is 4.5- to 9-m tall and
75 to 150 mm in diameter, but also occurs on drier,
nutrient-deficient upland sites and as a shrub or as
krummhoh at altitudinal treelines <832 m. Stem
densities of mature trees average 300 ha"1 on moist
sites.
Black spruce dominates cold, wet sites with low
pH, low base element saturation, long turnover times
for nutrients and organic matter, high biomass accu-
mulation, and low element concentrations. Mosses
compete for and trap nutrients on these sites, account
for significant proportions of community production,
and cause paludification, which can produce
sparsely treed Sphagnum bogs in the absence of fire.
Nevertheless, slow growth, low palatability to herbi-
vores, and reproduction by both sexual and vegeta-
tive (layering) means adapt black spruce to these
low-nutrient environments.
BLACK SPRUCE WETLANDS
Vegetation, soils, and hydrologic characteristics
are the chief criteria for delineating wetlands in
North America. Wetland hydrology drives wetland
formation and usually produces hydric soils and hy-
drophytic vegetation. Wetland hydrology can occur
where bedrock, marine or lacustrine clays, glacial
tills, or permafrost impede drainage. Impeded drain-
age often exists in lowlands and on slopes underlain
by permafrost in the Subarctic.
In North American taiga, black spruce, some-
times growing in mixed stands with tamarack, is the
tree species most often associated with treed wet-
lands. Some BSWs are peatlands or mires, peat-
forming ecosystems having >0.4 m peat thickness
and generally separated into bogs and fens. Bogs are
ombrotrophic mires, meaning they receive water
exclusively as precipitation, which typically has a
low nutrient content. Fens are minerotrophic mires,
meaning they receive water that contains moderate
to high concentrations of nutrients from contact with
mineral soil.
Black spruce occurs in both bogs and fens but
does not occupy wet extremes of mire moisture gra-
dients. Sphagnum mosses dominate ground cover in
bogs and graminoids in fens. Lichens occur on peat
surfaces too dry to support mosses.
Black spruce wetlands with Histosols, soils hav-
ing >0.4 m of organic material, are mires, but peat-
forming BSWs with histic epipedons (organic layers
ranging from 0.2 to 0.4 m) are not mires by Cana-
dian usage. Black spruce wetlands with histic
epipedons occupy a continuum from mire to sites
possibly influenced by mineral soils. Sites support-
ing dwarf trees (<3-m tall) have higher probabilities
of being mires than do sites supporting larger trees,
but black spruce forests and woodlands also can be
mires or have mire inclusions.
Black spruce wetlands primarily fall within the
Palustrine Forested Needle-leaved Evergreen and
Palustrine Scrub-Shrub Needle-leaved Evergreen
classes of the U.S. Fish and Wildlife Service classi-
fication system. Sparsely treed (<30%) graminoid
BSWs with few shrubs could fall within the
Palustrine Emergent Wetland class. Black spruce is
more closely associated with ombrotrophic than
minerotrophic conditions but is found in both types
of mire. Common plant taxa in BSWs include black
spruce, tamarack, willows, ericaceous shrubs, shrub
birches, buckbean, sedges, cotton grasses, horsetails,
Sphagnum and brown mosses, and lichens.
Black spruce community types of interior Alaska
have varying probabilities of occurring in wetlands.
Based on published descriptions of dominant vegeta-
tion, soil moisture conditions, presence or absence of
permafrost, slope, and aspect, six common commu-
nity types array from highest to lowest probability of
being wetland as follows: Picea mariana/Sphagnum
spp.-Cladina spp., Picea mariana/Vaccinium
uliginosum-Ledum groenlandicum/Pleurozium
schreberi, Picea mariana-Betula papyrifera/
124
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Summary and Conclusions
Vaccinium uliginosum-Ledum groenlandicum, Picea
marzana/feathermoss-lichen, Picea mariana-Picea
glauca/Betula glandulosaAichen, and Populus
tremuloides-Picea mariana/Cornus canadensis.
Site-specific investigation of soils and hydrology
may be necessary to delineate BSWs within a given
community type.
Activities potentially affecting BSWs include
filling, draining, flooding (wetland conversion), or
clearing; disposing of wastes; or mining peat depos-
its. Fill provides stable surfaces for transportation,
building construction, or resource development but
physically buries wetlands, radically changing their
functions and values. Draining wetlands facilitates
residential and commercial development, transporta-
tion, agriculture, and forestry. Stripping vegetation to
thaw permafrost can internally drain BSWs. Drain-
age effects include lower water tables, accelerated
peat decomposition, and subsidence of ground sur-
faces. Flooding wetlands converts them to shallow
or deep open-water habitats and generally alters their
functions. Effects of flooding BSWs include
thermokarst development, altered vegetation, and
transition from ombrotrophic to minerotrophic con-
ditions.
Activities such as powerline installation and
maintenance, pipeline construction, agricultural de-
velopment, and logging clear BSWs. Effects include
rutting and compaction of peat, reduced aerial biom-
ass and plant species diversity, habitat alteration and
fragmentation, nutrient depletion, erosion, and
thermokarst development. Disposal of solid wastes
in wetlands produces the same impacts as placement
of fill but is accompanied by the potential for
groundwater contamination by toxic substances.
Liquid wastes such as sewage effluent can be treated
in wetlands, but effects may include flooding, altered
vegetation, and reduced species diversity. Peat min-
ing on a commercial scale alters wetland character-
istics. Effects include those of drainage and clearing
as well as removal of organic substrates and elevated
export of nutrients.
Scientists have not systematically studied the
functions and values of BSWs, but silvicultural and
ecologic research on black spruce forests and mires,
research in individual disciplines related to wetland
functions, and directed research on wetland func-
tions conducted in areas outside the distribution of
black spruce are applicable. Silvicultural research
related to black spruce has focused on methods to
improve timber production and promote regenera-
tion following harvest. Studies of ecosystem struc-
ture and function that include well-treed BSWs
reveal wetland functions. Very little physical science
research in Alaska and northern Canada directly ex-
amines wetland functions of BSWs, but hydrologic
and water quality (including water chemistry) stud-
ies that include BSWs can be interpreted to charac-
terize these functions.
Specific studies of mires have largely focused on
their hydrology, soil and water chemistry, and veg-
etation. Eurasian studies of mire classification, veg-
etation, stratigraphy, uses, and sensitivity to impacts
supplement studies conducted in northern Minnesota
and Canada. Canadian research documents the
stratigraphy, morphology, and vegetation of taiga
mires, including the role of permafrost but usually
does not directly address wetland functions. Several
Alaskan studies document characteristics and devel-
opment of taiga mires, and others address hydrology
and permafrost, but none specifically treat mire
functions. Integrated knowledge of BSWs in Alaska
is sparse, but many lines of evidence from a variety
of locations and disciplines are applicable.
HYDROLOGIC FUNCTIONS
Groundwater discharge, groundwater recharge,
flow regulation, and erosion control are hydrologic
functions of wetlands. Ombrotrophic BSWs, includ-
ing bogs, do not perform the ground water-discharge
function. Minerotrophic BSWs perform the ground-
water-discharge function if they are supplied by up-
ward groundwater flow. Landscape position and
piezometric, water chemistry, or water balance data
can document such flow.
The groundwater-discharge function of
minerotrophic BSWs is impaired or eliminated by
fill placement within the area of discharge. Drains
beneath the fill might maintain discharge but usually
freeze and fail on permafrost soils. Wetland drainage
is unlikely to adversely affect the water-supply as-
pect of the groundwater-discharge function of
minerotrophic BSWs.
Ombrotrophic BSWs perform the groundwater-
recharge function, but the magnitude of recharge
generally is small and only applies to
suprapermafrost groundwater in regions of wide-
spread discontinuous permafrost. Minerotrophic
725
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Functional Profile of Black Spruce Wetlands in Alaska
BSWs do not perform the groundwater-recharge
function unless site-specific piezometric or water-
balance studies show otherwise. Trophic status and
permafrost extent indicate recharge potential and
whether such recharge will affect subpermafrost
groundwater.
The groundwater-recharge function of BSWs is
sensitive to fill placement and drainage, which con-
vert potential or actual groundwater flows to surface
flows. Directing fill runoff to adjacent undisturbed
wetlands capable of recharging groundwater could
compensate for lost recharge area, if runoff loading
of the remaining wetlands did not exceed their infil-
tration capacity. The detrimental effect of drainage
on groundwater recharge is ameliorated by the rela-
tively low hydraulic conductivity of sapric peat,
which renders effective drainage difficult and expen-
sive.
Black spruce wetlands perform the flow-regula-
tion function through microtopographic detention
and depression storage, subsurface storage of snow-
melt and precipitation, and evapotranspiration, but
the magnitude of this function generally is small,
often limited by the position of the water table.
Minerotrophic BSWs fed by subpermafrost ground-
water provide long-term baseflows, but BSWs sup-
plied by suprapermafrost groundwater provide only
quantitatively small, short-term baseflows. Black
spruce wetlands generally regulate flow less effec-
tively than vegetated, well-drained uplands of low to
moderate slope.
Slope may indicate hydraulic response and water
balance characteristics for ombrotrophic BSWs.
Groundwater discharge indicates the ability of a
minerotrophic BSW to provide baseflows but is a
negative indictor for subsurface storage.
Fill and drainage diminish the flow-regulation
function of ombrotrophic BSWs, and minerotrophic
BSWs that do not discharge groundwater, by reduc-
ing storage and speeding surface runoff. For
minerotrophic BSWs that discharge groundwater, fill
reduces potential baseflows to streams. Highly-per-
meable fill or subdrains on nonpermafrost soils
could maintain groundwater discharge for down-
stream water supplies. Little mitigation for loss of
other aspects of flow regulation appears feasible
without extensive hydraulic engineering.
Black spruce wetlands perform the erosion-con-
trol function by insulating permafrost soils and by
mantling credible mineral soils with a layer of peat.
The magnitude of this function may not greatly ex-
ceed that of well-drained, mature, upland forest
stands. Thickness of the organic mat may indicate
potential effectiveness of the erosion-control func-
tion. The erosion-control function of BSWs probably
is only slightly sensitive to fill placement if the or-
ganic mat is intact but somewhat more sensitive to
ditching that exposes mineral soil or ice-rich mate-
rials.
Black spruce wetlands perform hydrologic func-
tions to varying degrees, primarily determined by
trophic status. In general, the magnitudes of hydro-
logic functions of BSWs are small. Hydrologic func-
tions of BSWs are relatively less important than their
water quality and ecologic functions.
Data gaps exist with respect to groundwater dis-
charge and recharge, flow regulation, and sensitivity
of hydrologic functions to impacts of fill placement
and drainage. These gaps include relationships be-
tween groundwater discharge and minerotrophic
BSW vegetation and morphology, the distribution
and abundance of groundwater-discharge wetlands,
effectiveness of BSWs for groundwater recharge,
flow regulation by lowland (flat) BSWs, biological
importance of baseflows originating in
minerotrophic BSWs, effect of drainage on water
balances of permafrost BSWs, and effects of fills on
hydrologic functions of BSWs.
WATER QUALITY FUNCTIONS
Sediment retention, nutrient uptake, nutrient
transformation, and contaminant removal are water
quality functions of wetlands. Black spruce wetlands
appear to perform the sediment-retention function.
Minerotrophic BSWs have a greater opportunity to
remove suspended solids from the water column
than do ombrotrophic BSWs. Indicators of the sedi-
ment-retention function include visible sediment
deposits or microtopographic features that slow wa-
ter movement.
The sediment-retention function of BSWs is sen-
sitive to placement of fill, which often increases
sediment loading on remaining wetlands, and to
drainage, which may generate solids. Minerotrophic
BSWs with surface flow are more sensitive to drain-
age than are precipitation-driven BSWs. Mitigation
might include armoring fill surfaces and drainage
ditches and constructing settling ponds.
726
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Summary and Conclusions
Black spruce wetlands perform the nutrient-up-
take function; this function also occurs in well-
drained uplands. Plants characteristic of
nutrient-poor ombrotrophic and weakly
minerotrophic wetlands can assimilate anthropo-
genic nutrients, as can plants adapted to the high
nutrient levels of minerotrophic BSWs. Because all
plant communities take up nutrients from their envi-
ronments, no specific indicators of the nutrient-up-
take function need be applied to vegetated wetlands.
The nutrient-uptake function of BSWs is sensi-
tive to fill, which, unless vegetated, has little capac-
ity for nutrient uptake. Revegetating fill surfaces to
achieve dense vegetative cover could ameliorate
excessive nutrient loading from fill runoff in the
absence of high anthropogenic nutrient inputs (e.g.,
fertilization), but such surfaces could not remove
waterbome nutrients within the wetland. Draining
BSWs reduces, but does not eliminate, uptake of
waterbome nutrients by wetland plants by channel-
ing flow and reducing nutrient residence time. Main-
taining a vegetated surface would partially mitigate
drainage impacts on nutrient uptake.
Black spruce wetlands perform the nutrient-
transformation function for nitrogen (N) and phos-
phorus (P), tending to make inorganic forms less
available, and are sinks for nutrient elements.
Ombrotrophic BSWs may reduce nutrient availabil-
ity and fix N to a greater extent than do
minerotrophic BSWs. Minerotrophic BSWs may
mineralize more nutrients, have greater plant uptake
of nutrients, and adsorb more P than do
ombrotrophic BSWs. Accumulating organic matter
indicates nutrient immobilization, and trophic status
indicates details of nutrient transformations in a
given BSW.
The nutrient-transformation function of BSWs is
sensitive to placement of fill, which buries the me-
dia responsible for such transformations, but is less
sensitive to drainage. Establishing dense vegetation,
including N-fixing species, on fill surfaces could
mitigate some fill-induced impacts. On-site mitiga-
tion of altered patterns of nutrient transformation in
drained BSWs does not appear possible without re-
storing lowered water tables to their original posi-
tions.
Black spruce wetlands perform the contaminant-
removal function by taking up and storing metals,
immobilizing nutrients, and, in some cases, buffer-
ing inputs of acids but do not effectively degrade
hydrocarbons or, by extension, other toxic organic
compounds. Minerotrophy, perhaps supplemented
by the presence of acid-buffering vegetation such as
tamarack and Labrador-tea, indicates acid buffering
capacity, and rapidly accumulating organic matter
indicates high nutrient immobilization.
The contaminant-removal function of BSWs is
sensitive to placement of fill, which buries chemical
and biotic media responsible for the function, but is
less sensitive to drainage. Mitigation might include
calcareous fill to buffer acid deposition, manipulat-
ing warm, aerobic fill surfaces to degrade organic
contaminants, and creating constructed wetlands for
uptake of metals. Restoring water tables of BSWs to
predisturbance elevations would mitigate the effects
of drainage on the contaminant-removal function.
Black spruce wetlands perform water quality
functions. In general, the magnitudes of these func-
tions are large. Black spruce wetlands are nutrient
sinks that offer a range of pH values to facilitate
various chemical processes related to water quality.
The water quality functions of BSWs appear much
more important than their hydrologic functions.
Data gaps exist with respect to the water quality
functions of Alaska's BSWs and their sensitivities to
fill and drainage. These gaps include studies of sedi-
ment retention by individual BSWs as opposed to
watersheds containing BSWs, nutrient uptake in the
wetter ombrotrophic BSWs and most minerotrophic
BSWs, P uptake in minerotrophic BSWs, P precipi-
tation and adsorption hi all BSWs, nitrification and
denitrification in all BSWs, metal uptake and plaque
formation in minerotrophic BSWs, nutrient content
of minerotrophic peat, controls on peat accumulation
in BSWs, acid-buffering capacities of BSWs, effects
of drainage on nutrient transformation and contami-
nant removal in BSWs, and effects of drainage on
net accumulation of organic matter in BSWs.
GLOBAL BIOGEOCHEMICAL FUNCTIONS
Black spruce wetlands function to fix carbon (C)
by photosynthesis, store C as organic matter, and
release stored C as CH4 and CO2 by decomposition
and fire. Saturated conditions in BSWs minimize
release of C as compared to nonwetlands. Active
accumulation of organic matter indicates C storage
in BSWs. High water tables and low redox potentials
indicate potential CH4 emission whereas aerobic
727
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Functional Profile of Black Spruce Wetlands in Alaska
surface layers indicate potential CO2 emission.
The C cycling and storage functions of BSWs is
sensitive to placement of fill, which eliminates the
vegetation responsible for C fixation. Establishing
dense vegetation on a fill surface could mitigate loss
of C fixation by wetland plants but would not fully
mitigate loss of C storage because most C would
return to the atmosphere by rapid decomposition.
The effects of drainage on the C cycling and storage
function of BSWs are not clear.
Black spruce wetlands are important sinks for at-
mospheric C. This function is very important with
respect to global climate and helping to ameliorate
anthropogenic release of CO2. Documentation of net
C balance for a variety of BSWs, as influenced by
trophic status, community composition, and hydro-
logic relationships, is warranted given the impor-
tance of CO2 as a greenhouse gas.
ECOLOGIC FUNCTIONS
Nutrient cycling, nutrient export, food-chain sup-
port, and fish and wildlife habitat are ecologic func-
tions of wetlands. Black spruce wetlands perform the
nutrient-cycling function. Minerotrophic BSWs
likely cycle more nutrients than do ombrotrophic
BSWs but are unlikely to approach the nutrient-cy-
cling capabilities of upland deciduous forests.
Trophic status may be an indicator of nutrient-cy-
cling rates in BSWs.
The nutrient-cycling function of BSWs is more
sensitive to placement of fill than to drainage be-
cause fill buries media responsible for the function.
Nutrient cycling could be re-established on fill sur-
faces covered by dense vegetation. Perhaps the only
predictions possible with regard to nutrient cycling
and drainage of BSWs are that increased decompo-
sition coupled with increased net primary production
indicate increased nutrient cycling whereas de-
creased decomposition coupled with decreased net
primary production indicate decreased nutrient cy-
cling. Manipulating the balance of decomposition
and production in drained wetlands to simulate
predrainage states might mitigate impacts on nutri-
ent cycling.
Black spruce wetlands with outflows perform the
nutrient-export function, but the magnitude of such
export is small. Minerotrophic BSWs may export
more N and P than do ombrotrophic wetlands, but
ombrotrophic BSWs may export more C than do
minerotrophic wetlands. Discharge of water from a
BSW indicates some nutrient export, specifically C
if tannic stained, as do highly decomposed wetland
surfaces.
,The nutrient-export function of BSWs is sensi-
tive to placement of fill, although the effects are am-
biguous for N and P, but is enhanced by drainage.
Flows emanating from fill surfaces and the concen-
trations of nutrients in those flows might be adjusted
to match natural conditions to mitigate impacts on
the nutrient-export function. Mitigating the positive
effects of drainage on the nutrient-export function of
BSWs appears unlikely.
Black spruce wetlands support grazing and detri-
tal food chains and thus perform the food-chain sup-
port function. The magnitude of this function
appears to be greater in minerotrophic BSWs than in
ombrotrophic BSWs. Although the food-chain sup-
port function of BSWs, measured by community
production, is lower than that of well-drained taiga
uplands, it is essential to organisms limited to wet-
land environments. Trophic status and direct obser-
vation of animal use or presence of forage may
indicate the potential magnitude of food chain sup-
port by BSWs.
The food chain-support function of BSWs is
much more sensitive to placement of fill, which
eliminates primary production, than to drainage that
leaves vegetated surfaces. Re-establishment of veg-
etative cover, particularly that emulating the undis-
turbed wetland, could mitigate the effects of fill
placement on food chains but is unlikely to be com-
patible with fill purposes. Drainage may increase net
primary production, particularly that of trees. Habi-
tat manipulation might be used to mitigate shifts in
dominance by plant species and potential losses in
productivity in drained BSWs.
Alaska's BSWs directly provide habitat to a large
number of avian species, especially passerines, a
smaller number of mammalian species, and one
amphibian species. A large number of waterbirds use
waterbodies associated with BSWs, but inclusion of
these species in the habitat function of BSWs largely
is a matter of the scale at which habitat is addressed.
Excluding waterbirds, only about 12 nonraptorial
bird species, 7 raptorial bird species, and 13 mam-
malian species might be judged commonly and con-
sistently present in BSWs. Moose and caribou,
although important users of BSWs, do not appear in
128
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Summary and Conclusions
these totals because other plant communities are
their preferred habitats.
Trophic status might prove a good predictor for
presence or absence of selected avian or mammalian
species, but such relationships rarely have been
tested. Directly sensing avian and mammalian spe-
cies or their vocalizations, nests, droppings, tracks,
preferred forage, browsed or cropped stems, bur-
rows, or dens best evaluates the habitat function of
BSWs.
The habitat function of BSWs is much more sen-
sitive to placement of fill, which eliminates food and
cover, than to drainage that leaves natural vegetation
intact. Revegetating fill surfaces might partially miti-
gate habitat impacts of fill placement, but re-estab-
lishment of cover structure and food density
characteristic of the original BSW would be ex-
tremely difficult. Habitat manipulation might mini-
mize changes in plant species composition brought
about by wetland drainage, and carefully designed
artificial ponds could replace lost open-water habi-
tats.
Black spruce wetlands perform ecologic func-
tions. The magnitudes of nutrient-cycling, nutrient-
export, and food chain-support functions of
ombrotrophic and weakly minerotrophic BSWs are
limited in comparison with those of highly
minerotrophic wetlands and, in some cases, well-
drained uplands. The habitat function of BSWs is
important to most taiga birds and mammals. As a
group, the ecologic functions of black spruce wet-
lands are relatively more important than their hydro-
logic functions, comparing favorably with their
water quality functions.
Data gaps exist with respect to the ecologic func-
tions of Alaska's BSWs. Addressing these gaps
would require studies of nutrient cycling in sparsely
treed BSWs, trophic controls on nutrient cycling in
BSWs, nutrient export from all BSWs, the ecologic
role of exported C in brownwater systems, primary
production in sparsely treed BSWs, partitioning of
energy flows between grazing and detrital food
chains in all BSWs, effects of trophic status on par-
titioning of energy flows, secondary production sup-
ported by BSWs, synecology of BSWs in relation to
trophic status and vegetation structure and composi-
tion, effects of drainage on nutrient cycling by
BSWs in relation to trophic status, effects of fill and
drainage on nutrient export, effects of drainage on
partitioning of energy flows and food chain support,
mitigation techniques for habitat losses to fill, and
effects of drainage on plant species composition.
SOCIOECONOMIC USES
Subsistence, personal, and commercial harvests
of wetland-dependent fish, wildlife, and plant re-
sources are the most important consumptive uses of
Alaska's BSWs. Consumptive uses of nonrenewable
resources such as peat, gravel, and placer and
hardrock minerals occurring in or beneath BSWs
currently are few in Alaska. The magnitude of con-
sumptive uses of BSWs perhaps is best judged
through regional and local socioeconomic studies.
Consumptive use of wetland-dependent renew-
able resources is more sensitive to placement of fill,
which eliminates primary production and animal
habitats and buries nonrenewable resources, than to
drainage that leaves natural vegetation intact. Re-
establishment of productive animal habitats on fill
surfaces and minimization of fill depths could miti-
gate fill impacts. Habitat manipulation designed to
maintain populations of fish and wildlife species
dependent upon BSWs might mitigate adverse ef-
fects of drainage on consumptive use of those popu-
lations.
Active recreation in BSWs, particularly in winter,
appears to constitute their major nonconsumptive
use. Less active uses of these wetlands include open
space, biodiversity, nature study, research, rare spe-
cies, and geomorphic features. Nonconsumptive
uses of BSWs are best documented through local
and regional surveys, studies, or plans related to
outdoor recreation, heritage sites, and land use.
Nonconsumptive uses of BSWs vary in their sen-
sitivity to fill placement and drainage. Fill placement
and drainage enhance most means of transportation
across mires but diminish passive recreation or heri-
tage site uses. Re-establishment of diverse natural
communities on fill surfaces could mitigate some
adverse impacts. Most adverse impacts of drainage
on nonconsumptive uses of BSWs would be difficult
to mitigate and would require different techniques
for different uses. Habitat manipulation might miti-
gate the impacts of wetland drainage on some rare
species but is unlikely to meet the needs of obligate
wetland plants.
Black spruce wetlands provide for socioeco-
nomic uses. The magnitude of consumptive uses
729
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V*
Functional Profile of Black Spruce Wetlands in Alaska
probably exceeds that of nonconsumptive uses,
based on the importance of harvests of fish, wildlife,
and plant materials in Alaska's socioeconomic fab-
ric. Comparison of socioeconomic uses of BSWs
with their wetland functions may not be fully appro-
priate, but the importance of such uses appears to
compare favorably with the importance of ecologic
and water quality functions.
Few studies directly address socioeconomic uses
of BSWs. Filling data gaps would require studies of
the relationships between wild harvests and various
types of BSWs, synecology of BSWs, distribution
and abundance of peat and mineral resources in re-
lation to BSWs, nonconsumptive uses of BSWs
through scientific surveys and direct observations,
impacts of wetland loss on wild harvests, effects of
BSWs on adjacent waterbodies and fisheries re-
sources, effects of drainage on plant communities,
CONCLUSIONS
Black spruce wetlands are prominent features in
taiga landscapes. These features have been cast as
having little biological or socioeconomic impor-
tance. Examination of the characteristics of Alaska's
BSWs reveals that they perform low-magnitude hy-
drologic functions, perform several substantial wa-
ter quality and ecologic functions, and provide for
important socioeconomic uses.
Characteristics which limit the hydrologic func-
tions of BSWs, particularly ombrotrophic wetlands,
include permafrost and the low hydraulic conduc-
tivities of decomposed peat. These characteristics
impede exchange of deep and near-surface ground-
water, speed surface and near-surface runoff, and re-
duce baseflows.
Characteristics which enhance the water quality
functions of BSWs include peat and peat-forming
vegetation. Peat-forming vegetation such as Sphag-
num mosses compete for nutrients and form a sedi-
ment-trapping microtopography in bogs. Some
vegetation responds to nutrient input with increased
uptake. Peat accumulation sequesters nutrients and
contaminants.
Characteristics which influence the ecologic
functions of BSWs include their extensive distribu-
tion and their trophic status. Most of Alaska's birds
and mammals appear adapted to use BSW habitats to
greater or lesser degrees. Ombrotrophy limits nutri-
ent cycling and food chain support, but
minerotrophy enhances these functions.
Socioeconomic uses of Alaska's BSWs appear
strongly influenced by the strength of their ecologic
functions, particularly the habitat function.
130
-------
LITERATURE CITED
Abbott, S.M., editor. 1993. Furbearers. Alaska Dep. Fish
Game Surv.-Inventory Manage. Rep., 1 July 1989 -
30 June 1991, Fed. Aid Wildl. Restor. Proj. W-23-3,
W-23-4, Stud. 7.0. 303pp.
Adamus, P.R., and L.T. Stockwell. 1983. A method for
wetland functional assessment: Vol. I. Critical review
and evaluation concepts. U.S. Dep. Transport. Rep.
No. FHWA-IP-82-23. 162pp. + appendices.
Ager, T.A. 1975. Late Quaternary environmental history
of the Tanana Valley, Alaska. Ohio State Univ. Inst.
Polar Stud. Rep. No. 54. 117pp.
Aksamit, S.E., and F.D. Irving. 1984. Prescribed burning
for lowland black spruce regeneration in northern
Minnesota. Can. J. For. Res. 14(1): 107-113.
Aldrich, J.W., and C.W. Slaughter. 1983. Soil erosion on
subarctic forest slopes. J. Soil and Water Conserv.
38(2):115-118.
Alexander, V, and M.M. Billington. 1986. Nitrogen fixa-
tion in the Alaskan taiga. Pages 112-120 in K. Van
Cleve, F.S. Chapin, III, P.W. Flanagan, L.A. Viereck,
and C.T. Dyrness, eds. Forest ecosystems in the Alas-
kan taiga. Springer-Verlag, New York.
Almendinger, J.C., J.E. Almendinger, and P.H. Glaser.
1986. Topographic fluctuations across a spring fen
and raised bog in the Lost River Peatland, northern
Minnesota. J. Ecol. 74(2):393-401.
Ambrose, R.E. 1982. Prey of the peregrine falcon on the
upper Yukon River in Alaska and the habitat of the
prey species [Abstract]. Page 187 in T.J. Cade, J.H.
Enderson, C.G. Thelander, and C.M. White, eds. Per-
egrine falcon populations: their management and re-
covery. The Peregrine Fund, Inc., Boise, Id.
, R.J. Ritchie, C.M. White, P.P. Schempf, T. Swem,
and R. Dittrick. 1988. Changes in the status of per-
egrine falcon populations in Alaska. Pages 73-82 in
T.J. Cade, J.H. Enderson, C.G. Thelander, and C.M.
White, eds. Peregrine falcon populations: their man-
agement and recovery. The Peregrine Fund, Inc.,
Boise, Id.
American Public Health Association, American Water
Works Association, and Water Environment Federa-
tion. 1992. Standard methods for the examination of
water and wastewater. Eighteenth ed. Am. Public
Health Assoc., Washington, D.C.
Andrews, E.F. 1988. The harvest of fish and wildlife for
subsistence by residents of Minto, Alaska. Alaska
Dep. Fish Game Div. Subsistence Tech. Pap. No.
137. 334pp.
Anonymous. 1989. Alaskan's per capita harvests of wild
foods. Alaska Fish & Game 21(6): 14-15.
Armstrong, R.H. 1990. Guide to the birds of Alaska.
Alaska Northwest Books, Seattle. 342pp.
Arnold, T.W., and E.K. Fritzell. 1990. Habitat use by male
mink in relation to wetland characteristics and avian
prey abundances. Can. J. Zool. 68:2205-2208.
Backeus, I. 1990. Production and depth distribution of
fine roots in a boreal open bog. Ann. Bot. Fenn.
27:261-265.
Baker, J.A., and R.J. Brooks. 1981. Raptor and vole popu-
lations at an airport. J. Wildl. Manage. 45(2): 390-
396.
Ballard, W.B., J.S. Whitman, and D.J. Reed. 1991. Popu-
lation dynamics of moose in south-central Alaska.
Wildl. Monogr. 114:1-49.
Baranovskiy, A.Z. 1991. Alteration of peat bog soils by
cropping with perennial grasses. Soviet. Soil Sci.
23(l):35-42.
Bartsch, I. 1994. Effects of fertilization on growth and nu-
trient use by Chamaedaphne calyculata in a raised
bog. Can. J. Bot. 72:323-329.
, and C. Schwintzer. 1994. Growth of
Chamaedaphne calyculata at two peatland sites in
relation to nutrient availability. Wetlands 14(2): 147-
158.
Batten, A.R. 1990. A synopsis of Alaska wetland vegeta-
tion. Pages 23-44 in A. van der Valk and J. Hall, eds.
Alaska: regional wetland functions. [Proc. workshop,
Anchorage, Alas., 1986] Environ. Inst. Univ. Mass.
131
-------
Functional Profile of Black Spruce Wetlands in Alaska
Publ. No. 90-1.
Batzli, G.O., and F.A. Pitelka. 1983. Nutritional ecology
of microtine rodents: food habits of lemmings near
Barrow, Alaska. J. Mammal. 64(4):648-655.
, R.G. White, S.F. MacLean, Jr., F.A. Pitelka, and
B.D. Collier. 1980. The herbivore-based trophic sys-
tem. Pages 335-410 in J. Brown, P.C. Miller, L.L.
Tieszen, and EL. Bunnell, eds. An arctic ecosystem:
the coastal tundra at Barrow, Alaska. Dowden,
Hutchinson & Ross, Inc., Stroudsburg, Penn.
Bay, R.R. 1969. Runoff from small peatland watersheds.
J. Hydrol. 9(1):90-102.
Bekoff, M. 1977. Canis latrans. Mamm. Species 79:1-9.
. 1982. Coyote. Pages 447-459 in J.A. Chapman
and G.A. Feldhamer, eds. Wild mammals of North
American: biology, management, and economics.
Johns Hopkins Univ. Press, Baltimore and London.
Bellrose, F.C. 1980. Ducks, geese & swans of North
America: Third ed. Stackpole Books, Harrisburg, Pa.
540pp.
Beneski, J.T., Jr., and D.W. Stinson. 1987. Sorexpalustris.
Mamm. Species 296:1-6.
Benninghoff, W.S. 1963. Relationships between vegeta-
tion and frost in soils. Pages 9-13 in Int. Conference
on Permafrost, Lafayette, Ind., 1963. [Proc.] Natl.
Acad. Sci. - Natl. Res. Counc. Publ. No. 1287, Wash-
ington, D.C.
Bent, A.C. 1937. Life histories of North American birds
of prey. Part 1. Smithsonian Inst. U.S. Natl. Mus.
Bull. 167. 409pp. [Republished in 1961 by Dover
Publ., Inc., New York.]
. 1938. Life histories of North American birds of
prey. Part 2. Smithsonian Inst. U.S. Natl. Mus. Bull.
170. 482pp. [Republished in 1961 by Dover Publ.,
Inc., New York.]
_. 1939. Life histories of North American woodpeck-
ers. Smithsonian Inst. U.S. Natl. Mus. Bull. 174.
334pp. + plates. [Republished in 1964 by Dover
Publ., Inc., New York.]
Billings, W.D., K.M. Peterson, J.O. Luken, and D.A.
Mortensen. 1984. Interaction of increasing atmo-
spheric carbon dioxide and soil nitrogen on the car-
bon balance of tundra microcosms. Oecologia
65:26-29.
Billington, M.M. 1981. Nitrogen fixation in a black
spruce (Picea mariana [Mill.] B.S.P.) forest in inte-
rior Alaska. M.S. Thesis, Univ. Alaska, Fairbanks.
92pp.
, and V. Alexander. 1983. Site-to-site variations in
nitrogenase activity in a subarctic black spruce forest.
Can. J. For. Res. 13:782-788.
Bishop, S.C., and R.D. Cameron. 1990. Habitat use by
post-parturient female caribou of the Central Arctic
Herd. Page 9 in Impacts of development on wildlife
in Alaska. [Abstracts] Alaska Chap. Wildl. Soc.
Annu. Meeting, Juneau, Alas., 1990.
Bittner, S.L., and O.J. Rongstad. 1982. Snowshoe hare
and allies. Pages 146-163 in J.A. Chapman and G.A.
Feldhamer, eds. Wild mammals of North American:
biology, management, and economics. Johns
Hopkins Univ. Press, Baltimore and London.
Black, R.A., and L.C. Bliss. 1978. Recovery sequence of
Picea mariana - Vaccinium uliginosum forests after
burning near Inuvik, Northwest Territories, Canada.
Can. J. Bot. 56:2020-2030.
Blancher, P.J., and O.K. McNicol. 1991. Tree swallow
diet in relation to wetland acidity. Can, J. Zool.
69:2629-2637.
Bliss, L.C. 1981. North American and Scandinavian tun-
dras and polar deserts. Pages 8-24 in L.C. Bliss, O.W.
Heal, and J.J. Moore, eds. Tundra ecosystems: a com-
parative analysis. Cambridge Univ. Press, Cam-
bridge, U.K.
Boelter, D.H., and E.S. Verry. 1977. Peatland and water in
the northern Lake States. U.S. For. Serv. North Cent.
For. Exp. Stn. Gen. Tech. Rep. NC-31. 22pp.
Boerger, H. 1981. Species composition, abundance and
emergence phenology of midges (Deiptera [sic]:
Chironomidae) in a brown-water stream of west-cen-
tral Alberta, Canada. Hydrobiologia 80:7-30.
Boertje, R.D. 1981. Nutritional ecology of the Denali cari-
bou herd. M.S. Thesis, Univ. Alaska, Fairbanks.
294pp.
. 1984. Seasonal diets of the Denali caribou herd,
Alaska. Arctic 37(2):161-165.
Bonan, G.B. 1990a. Carbon and nutrient cycling in North
American boreal forests. II. Biogeographic patterns.
Can. J. For. Res. 20:1077-1088.
. 1990ft. The sensitivity of carbon storage in the up-
land boreal forests of interior Alaska to climatic
change. Page 109 in Int. conference on the role of the
polar regions in global change, Fairbanks, Alas.,
1990. [Abstracts] Geophys. Inst. and Cent, for Glo-
bal Change and Arct. System Res., Univ. Alas.,
Fairbanks.
Botch, M.S., and V.V. Masing. 1983. Mire ecosystems in
the U.S.S.R. Pages 95-152 in A.J.P. Gore, ed. 4B.
Mires: swamp, bog, fen and moor - regional studies.
Elsevier Sci. Publ. Co., Amsterdam.
Bourbonniere, R.A. 1987. Organic geochemistry of bog
drainage waters. Pages 139-145 in C.D.A. Rubec and
R.P. Overend, compilers. Proc. Symposium '87 Wet-
lands/Peatlands, Edmonton, Alia., 1987.
- 1989. Distribution patterns of dissolved organic
matter fractions in natural waters from eastern
Canada. Org. Geochem. 14(1):97-107.
Boutin, S., B.S. Gilbert, C.J. Krebs, A.R.E. Sinclair, and
J.N.M. Smith. 1985. The role of dispersal in the
132
-------
Literature Cited
population dynamics of snowshoe hares. Can. J.
Zool. 63:106-115.
Bowling, S.A. 1979. Alaska's weather and climate. Pages
1-25 in G. Weller, ed. Alaska's weather and climate.
Geophys. Inst., Univ. Alaska, Fairbanks.
. 1984. The variability of the present climate of in-
terior Alaska. Pages 67-75 in J.H. McBeath, ed. The
potential effects of carbon dioxide-induced climatic
changes in Alaska. [Proc. conf.] Univ. Alaska-
Fairbanks School of Agric. and Land Resour. Man-
age. Misc. Publ. 83-1.
Bradbury, I.K., and J. Grace. 1983. Primary production in
wetlands. Pages 285-310 in A.J.P. Gore, ed. 4A.
Mires: swamp, bog, fen, and moor - general studies.
Elsevier Sci. Publ. Co., Amsterdam.
Brink, C.H. 1964. Spruce seed as a food of the squirrels
Tamiasciurus hudsonicus and Glaucomys sabrinus in
interior Alaska. M.S. Thesis, Univ. Alaska,
Fairbanks. 75pp.
Brinson, M.M. 1990. Riverine forests. Pages 87-141 in
A.E. Lugo, S. Brown, and M. Brinson, eds. 15. For-
ested wetlands. Elsevier Sci. Publ. Co., Amsterdam.
. 1993. A hydrogeomorphic classification for wet-
lands. U.S. Army Corps Eng. Wetlands Tech. Rep.
WRP-DE-4. 79pp. + appendix.
Brown, A., D.J. Kushner, and S.P. Mathur. 1987. Feasibil-
ity of assessing metal pollution in Canadian Shield
mining areas through analysis of peat soils. Pages
299-305 in C.D.A. Rubec and R.P. Overend, compil-
ers. Proc. Symposium '87 Wetlands/Peatlands,
Edmonton, Alta., 1987.
Brown, D.A., and R.P. Overend. 1993. Methane metabo-
lism in raised bogs of northern wetlands.
Geomicrobiol. J. 11:35-48.
Brown, R.G., and J.R. Stark. 1989. Hydrologic and water
quality characteristics of a wetland receiving waste-
water effluent in St. Joseph, Minnesota. Wetlands
9(2): 191-206.
Brown, R.J.E. 1963. Influence of vegetation on perma-
frost. Pages 20-25 in Int. Conference on Permafrost,
Lafayette, Ind., 1963. [Proc.] Natl. Acad. Sci. - Natl.
Res. Counc. Publ. No. 1287, Washington, D.C.
, and T.L. Pewe. 1973. Distribution of permafrost in
North America and its relationship to the environ-
ment: a review, 1963-1973. Pages 71-100 in Int. Con-
ference on Permafrost (Second), Yakutsk, U.S.S.R.,
1973. [North Am. Contrib.] Natl. Acad. Sci., Wash-
ington, D.C.
Brown, S. 1990. Structure and dynamics of basin forested
wetlands in North America. Pages 171-199 in A.E.
Lugo, S. Brown, and M. Brinson, eds. 15. Forested
wetlands. Elsevier Sci. Publ. Co., Amsterdam.
Brumelis, G., and T.J. Carleton. 1988. The vegetation of
postlogged black spruce lowlands in central Canada.
I. Trees and tall shrubs. Can. J. For. Res.
18(11):1470-1478.
, and . 1989. The vegetation of post-logged
black spruce lowlands in central Canada. II.
Understorey vegetation. J. Appl. Ecol. 26(1):321-
340.
Brunberg, J.C. 1983. Microbial activity in Alaskan taiga
black spruce (Picea mariana [Mill] B.S.P.) and paper
birch (Betula papyrifera Marsh.) forest floor with
regard to altered substrate quality. M.S. Thesis, Univ.
Alaska, Fairbanks. 163pp.
Bryant, J.P. 1984. Chemical defense of boreal woody
plants against vertebrate herbivores. Ph.D. Thesis,
Univ. Alaska, Fairbanks. 61pp. + 4 reprints + 2 ar-
ticles in press.
, and F.S. Chapin, III. 1986. Browsing-woody plant
interactions during boreal forest plant succession.
Pages 213-255 in K. Van Cleve, F.S. Chapin, III, P.W.
Flanagan, L.A. Viereck, and C.T. Dyrness, eds. For-
est ecosystems in the Alaskan taiga. Springer-Verlag,
New York.
, , and D.R. Klein. 1983. Carbon/nutrient bal-
ance of boreal plants in relation to vertebrate her-
bivory. Oikos 40:357-368.
_, and P.J. Kuropat. 1980. Selection of winter forage
by subarctic browsing vertebrates: the role of plant
chemistry. Annu. Rev. Ecol. Syst. 11:261-285.
Buckman, H.O., and N.C. Brady. 1969. The nature and
properties of soils. Seventh ed. The Macmillan Com-
pany/Collier-Macmillan Can., Ltd., Toronto. 653pp.
Burger, J., and M. Gochfeld. 1988. Habitat selection in
mew gulls: small colonies and site plasticity. Wilson
Bull. 100(3):395-410.
Burn, C.R., and M.W. Smith. 1988. Thermokarst lakes at
Mayo, Yukon Territory!'Canada. Pages 700-705 in K.
Senneset, ed. Int. Conference on Permafrost (Fifth),
Trondheim, Norway, 1988. [Proc. Vol. 1] Tapir Publ.,
Trondheim, Norway.
Burt, W.H., and R.P. Grossenheider. 1964. Afield guide to
the mammals. Second ed. Houghton Mifflin Co.,
Boston. 284pp.
Buskirk, S.W. 1983. The ecology of marten in
southcentral Alaska. Ph.D. Thesis, Univ. Alaska,
Fairbanks. 131pp.
. 1984. Seasonal use of resting sites by marten in
south-central Alaska. J. Wildl. Manage 48(3):950-
953.
Buttleman, C.G., and D.F. Grigal. 1985. Use of the Rb/K
ratio to evaluate potassium nutrition of peatlands.
Oikos 44:253-256.
Buttler, A.J., H. Dinel, M. Levesque, and S.P. Mathur.
1991. The relation between movement of subsurface
water and gaseous methane in a basin bog with a
novel instrument. Can. J. Soil Sci. 71:427-438.
133
-------
Functional Profile of Black Spruce Wetlands in Alaska
Calmes, M.A. 1976. Vegetation pattern of bottomland
bogs in the Fairbanks area, Alaska. M.S. Thesis,
Univ. Alaska, Fairbanks. 104pp.
Cameron, R.D., D.J. Reed, J.R. Dau, and W.T. Smith.
1992. Redistribution of calving caribou in response to
oil field development on the Arctic Slope of Alaska.
Arctic 45(4):338-342.
Carbyn, L.N. 1971. Densities and biomass relationships
of birds nesting in boreal forest habitats. Arctic
Carter, V., M.S. Bedinger, R.P. Novitzki, and W.O. Wilen.
1979. Water resources and wetlands (theme paper).
Pages 344-376 in P.E. Greeson, J.R. Clark, and I.E.
Clark, eds. Wetland functions and values: the state of
our understanding. [Proc. natl. symp. on wetlands,
Lake Buena Vista, Fla., 1978] Am. Water Resour.
Assoc., Minneapolis, Minn.
Chacho, E. F., Jr. 1990. Water and suspended solids dis-
charge during snowmelt in a discontinuous perma-
frost basin. Pages 167-173 in Permafrost - Canada.
[Proc. Fifth Can. Permafrost Conf., Collection
Nordicana No. 54, Laval Univ.] Natl. Res. Counc.
Can., Ottawa.
_ , and S. Bredthauer. 1983. Runoff from a small sub-
arctic watershed, Alaska. Pages 115-120 in Int. Con-
ference on Permafrost (Fourth), Fairbanks, Alas.,
1983. [Proc.] Natl. Acad. Press, Washington, D.C.
Chapin, F.S., III. 1974. Morphological and physiological
mechanisms of temperature compensation in phos-
phate absorption along a latitudinal gradient. Ecology
55:1180-1198.
_ . 1983a. Nitrogen and phosphorus nutrition and nu-
trient cycling by evergreen and deciduous understory
shrubs in an Alaskan black spruce forest. Can. J. For.
Res. 13:773-781.
_ . 1983/7. Adaptation of selected trees and grasses to
low availability of phosphorus. Plant and Soil
72:283-287.
_ . 1986. Controls over growth and nutrient use by
taiga forest trees. Pages 96- 1 1 1 in K. Van Cleve, F.S.
Chapin, III, P.W. Flanagan, L.A. Viereck, and C.T.
Dyrness, eds. Forest ecosystems in the Alaskan taiga.
Springer- Verlag, New York.
_ , and R.A. Kedrowski. 1983. Seasonal changes in
nitrogen and phosphorus fractions and autumn
retranslocation in evergreen and deciduous taiga
trees. Ecology 64(2):376-391.
_ , and PR. Tryon. 1983. Habitat and leaf habit as de-
terminants of growth, nutrient absorption, and nutri-
ent use by Alaskan taiga forest species. Can. J. For.
Res. 13:818-826.
_, and K. Van Cleve. 1983. Influence of phos-
phorus on growth and biomass distribution of Alas-
kan taiga tree seedlings. Can J. For. Res.
13:1092-1098.
Chesemore, D.L. 1967. Ecology of the arctic fox in north-
ern and western Alaska. M.S. Thesis, Univ. Alaska,
Fairbanks. 148pp.
Chrosciewicz, Z. 1980. Some practical methods for secur-
ing adequate postcut forest reproduction in Canada.
Pages 49-52 in M. Murray and R.M. Van Veldhuizen,
eds. Forest regeneration at high latitudes. [Proc. int.
workshop, Fairbanks, Alas., 1979] U.S. For. Serv.
Pac. Northwest For. Range Exp. Stn. Gen. Tech. Rep.
PNW-107.
Clark, R. J. 1975. A field study of the short-eared owl, Asia
flammeus (Pontoppidan), in North America. Wildl.
Monogr. 47:1-67.
, D.G. Smith, and L. Kelso. 1987. Distributional
status and literature of northern forest owls. Pages
47-55 in R.W. Nero, R.J. Clark, R.J. Knapton, and
R.H. Hamre, eds. Biology and conservation of north-
ern forest owls: symposium proceedings, Winnipeg,
Manit., 1987. U.S. For. Serv. Rocky Mt. For. Range
Exp. Stn. Gen. Tech. Rep. RM-142.
Clarke, R.G. 1982. Nest site selection by sharp-shinned
hawks in interior Alaska. Pages 155-162 in W.N.
Ladd and P.P. Schempf, eds. Proc. of a symposium
and workshop on raptor management and biology in
Alaska and western Canada. U.S. Fish Wildl. Serv.,
Alaska Reg. Off., FWS/AK/PROC-82.
. 1984. The sharp-shinned hawk (Accipiter striatus
Vieillot) in interior Alaska. M.S. Thesis. Univ.
Alaska, Fairbanks. 130pp.
Clausen, J.C., and K.N. Brooks. 1983a. Quality of runoff
from Minnesota peatlands: II. A method for assessing
mining impacts. Water Resour. Bull. 19(5):769-772.
, and . 1983i>. Quality of runoff from Minne-
sota peatlands: I. A characterization. Water Resour.
Bull. 19(5):763-767.
Clymo, R.S. 1983. Peat. Pages 159-224 in A.J.P. Gore, ed.
4A. Mires: swamp, bog, fen, and moor - general stud-
ies. Elsevier Sci. Publ. Co., Amsterdam.
Coady, J.W. 1982. Moose. Pages 902-922 in J.A.
Chapman and G.A. Feldhamer, eds. Wild mammals
of North American: biology, management, and eco-
nomics. Johns Hopkins Univ. Press, Baltimore and
London.
Cogbill, C.V. 1985. Dynamics of the boreal forests of the
Laurentian Highlands, Canada. Can. J. For. Res.
15:252-261.
Collins, C.M., R.K. Haugen, and R.A. Kreig. 1988. Natu-
ral ground temperatures in upland bedrock terrain,
interior Alaska. Pages 56-60 in K. Senneset, ed. Int.
Conference on Permafrost (Fifth), Trondheim, Nor-
way, 1988. [Proc. Vol. 1] Tapir Publ., Trondheim,
Norway.
Comeau, PL., and D.J. Bellamy. 1986. An ecological in-
134
-------
Literature Cited
terpretation of the chemistry of mire waters from se-
lected sites in eastern Canada. Can. J. Bot. 64:2576-
2581.
Conant, R. 1958. Afield guide to reptiles and amphibians
of the United States and Canada east of the 100th
meridian. Houghton Mifflin Co., Boston. 366pp.
Cooper, B.A., R.J. Ritchie, B.A. Anderson, and L.C.
Byrne. 1991. Alaska Over-The-Horizon Backscatter
Radar System: a synthesis of the avian research pro-
gram, 1987-1990. Final Rep. Prepared for Arct.
Environ. Inf. Data Center, Univ. Alaska-Fairbanks
and Dep. Air Force by Alaska Biol. Res., Fairbanks,
Alas. 309pp. + photographs.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe.
1979. Classification of wetlands and deepwater habi-
tats of the United States. U.S. Fish Wildl. Serv. FWS/
OBS-79/31. 131pp.
Cowell, D.W. 1983. Karst hydrogeology within a subarc-
tic peatland: Attawapiskat River, Hudson Bay Low-
land, Canada. J. Hydrol. 61:169-175.
Craighead, J.J., and J.A. Mitchell. 1982. Grizzly bear.
Pages 515-556 in J.A. Chapman and G.A.
Feldhamer, eds. Wild mammals of North American:
biology, management, and economics. Johns
Hopkins Univ. Press, Baltimore and London.
Crowder, A., S. Macfie, L. St-Cyr, T. Conlin, J. Badgery,
and P. Johnson-Green. 1987. Root iron plaques and
metal uptake by wetland plants. Pages 503-508 in
C.D.A. Rubec and R.P. Overend, compilers. Proc.
Symposium '87 Wetlands/Peatlands, Edmonton,
Alta., 1987.
Crow, J.H., and K.B. Macdonald. 1979. Wetland values:
secondary production. Pages 146-161 in P.E.
Greeson, J.R. Clark, and J.E. Clark, eds. Wetland
functions and values: the state of our understanding.
[Proc. natl. symp. on wetlands, Lake Buena Vista,
Fla., 1978] Am. Water Resour. Assoc., Minneapolis,
Minn.
Cwynar, L.C. 1988. Late Quaternary vegetation history of
Kettlehole Pond, southwestern Yukon. Can. J. For.
Res. 18:1270-1279.
, and R.W. Spear. 1991. Reversion of forest to tun-
dra in the central Yukon. Ecology 72(1):202-212.
Dahl, E. 1986. Zonation in arctic and alpine tundra and
fellfield ecobiomes. Pages 35-61 in N. Polunin, ed.
Ecosystem theory and application. John Wiley &
Sons, New York.
Dale, J.M., B. Freedman, and J. Kerekes. 1985. Acidity
and associated water chemistry of amphibian habitats
in Nova-Scotia. Can. J. Zool. 63(1):97-105.
Damman, A.H.W. 1987. Variation in ombrotrophy:
chemical differences among and within ombrotrophic
bogs. Pages 85-93 in C.D.A. Rubec and R.P.
Overend, compilers. Proc. Symposium '87 Wetlands/
Peatlands, Edmonton, Alta., 1987.
Dang, Q.L., and V.J. Lieffers. 1989. Assessment of pat-
terns of response of tree ring growth of black spruce
following peatland drainage. Can. J. For. Res.
19:924-929.
Davis, J.L., R.T. Shideler, and R.E. LeResche. 1978.
Movements and distribution of the Fortymile Cari-
bou Herd. Alaska Dep. Fish Game Final Rep., Fed.
Aid Wildl. Restor. Proj. W-17-6 and W-17-7, Job
3.15R. 42pp.
de la Cruz, A. A. 1979. Production and transport of detri-
tus in wetlands. Pages 162-174 in P.E. Greeson, J.R.
Clark, and J.E. Clark, eds. Wetland functions and
values: the state of our understanding. [Proc. natl.
symp. on wetlands, Lake Buena Vista, Fla., 1978]
Am. Water Resour. Assoc., Minneapolis, Minn.
Dennington, M, and B. Johnson. 1974. Studies of beaver
habitat in the Mackenzie Valley and northern Yukon.
Environ.-Social Comm., North. Pipelines Task Force
North. Oil Dev. Rep. No. 74-39. 169pp.
Dickinson, C.H. 1983. Micro-organisms in peatlands.
Pages 225-245 in A.J.P. Gore, ed. 4A. Mires: swamp,
bog, fen, and moor - general studies. Elsevier Sci.
Publ. Co., Amsterdam.
Dinel, H., S.P. Mathur, A. Brown, and M. Levesque. 1988.
A field study of the effect of depth on methane pro-
duction in peatland waters: equipment and prelimi-
nary results. J. Ecol. 76:1083-1091.
Dingman, S.L. 1971. Hydrology of the Glenn Creek wa-
tershed, Tanana River Basin, central Alaska. U.S.
Army Cold Reg. Res. Eng. Lab. Res. Rep. 297.
110pp.
. 1973. Effects of permafrost on stream flow char-
acteristics in the discontinuous permafrost zone of
central Alaska. Pages 447-453 in Int. Conference on
Permafrost (Second), Yakutsk, U.S.S.R., 1973.
[North Am. Contrib.] Natl. Acad. Sci., Washington,
D.C.
1975. Hydrologic effects of frozen ground: litera-
ture review and synthesis. U.S. Army Cold. Reg. Res.
Eng. Lab. Spec. Rep. 218. 55pp.
, and F.R. Koutz. 1974. Relations among vegeta-
tion, permafrost, and potential insolation in central
Alaska. Arct. and Alpine Res. 6(l):37-42.
Disc, N.B. 1992. Winter fluxes of methane from Minne-
sota peatlands. Biogeochemistry 17:71-83.
Dodge, W.E. 1982. Porcupines. Pages 355-366 in J.A.
Chapman and G.A. Feldhamer, eds. Wild mammals
of North American: biology, management, and eco-
nomics. Johns Hopkins Univ. Press, Baltimore and
London.
Douglass, R.J. 1977. Population dynamics, home ranges,
and habitat associations of the yellow-cheeked vole,
Microtus xanthognathus, in the Northwest Territo-
735
-------
Functional Profile of Black Spruce Wetlands in Alaska
ries. Can. Field-Nat. 91:237-247.
, and K.S. Douglass. 1977. Micro-habitat selection
of chestnut-cheeked voles (Microtus xanthognathus).
Can. Field-Nat. 91:72-74.
, L.G. Fisher, and M. Mair. 1983. Habitat selection
of wildfire on soil chemistry in four forest types in
interior Alaska. Can. J. For. Res. 19:1389-1396.
, L.A. Viereck, and K. Van Cleve. 1986. Fire in
and food habits of marten, Martes americana, in the
Northwest Territories. Can. Field-Nat. 97:71-74.
[Abstr. in Magoun and Johnson 1991]
DOWL Engineers. 1983. University of Alaska Mosquito
Lake wetlands study. Rep. prepared for Univ. Alaska,
Anchorage by DOWL Engineers, Anchorage, Alas.
49pp.
Drury, W.H., Jr. 1956. Bog flats and physiographic pro-
cesses in the Upper Kuskokwim River Region,
Alaska. Contrib. Gray Herbarium of Harvard Univ.
No. 178. Cambridge, Mass. 130pp.
Dubuc, L.J., W.B. Krohn, and R.B. Owen, Jr. 1990. Pre-
dicting occurrence of river otters by habitat on Mount
Desert Island, Maine. J. Wildl. Manage. 54(4):594-
599.
Duncan, J.R. 1987. Movement strategies, mortality, and
behavior of radio-marked great gray owls in south-
eastern Manitoba and northern Minnesota. Pages
101-107 in R.W. Nero, R.J. Clark, RJ. Knapton, and
R.H. Hamre, eds. Biology and conservation of north-
ern forest owls: symposium proceedings, Winnipeg,
Manit., 1987. U.S. For. Serv. Rocky Mt. For. Range
Exp. Stn. Gen. Tech. Rep. RM-142.
Duquette, L.S. 1984. Patterns of activity and their impli-
cations to the energy budget of migrating caribou.
M.S. Thesis, Univ. Alaska, Fairbanks. 95pp.
Durtsche, B.M., and W. Hobgood. 1990. Distribution,
movements and seasonal use areas of caribou in the
White Mountains National Recreation Area, Alaska,
1982-1988. Bur. Land Manage., BLM-Alaska Open
File Rep. 29. 9pp.
Dyrness, C.T. 1982. Control of depth to permafrost and
soil temperature by the forest floor in black spruce/
feathermoss communities. U.S. For. Serv. Pac. North-
west For. Range Exp. Stn. Res. Note PNW-396.
19pp.
, and D.F. Grigal. 1979. Vegetation-soil relation-
ships along a spruce forest transect in interior Alaska.
Can. J. Bot. 57:2644-2656.
, and R.A. Norum. 1983. The effects of experimen-
tal fires on black spruce forest floors in interior
Alaska. Can. J. For. Res. 13:879-893.
, , C.W. Slaughter, V. Van Ballenberghe, L.A.
Viereck, R.A. Werner, and J. Zasada. 1983. Pages
516-525 in R.W. Wein, R.R. Riewe, and I.R.
Methven, eds. Resources and dynamics of the Boreal
Zone. [Proc. conf., Thunder Bay, Ontario, 1982]
Assoc. Can. Univ. North. Stud.
_, K. Van Cleve, and J.D. Levison. 1989. The effect
taiga communities of interior Alaska. Pages 74-86 in
K. Van Cleve, F.S. Chapin, III, P.W. Flanagan, L.A.
Viereck, and C.T. Dyrness, eds. Forest ecosystems in
the Alaskan taiga. Springer-Verlag, New York.
Eberhardt, W.L. 1977. The biology of arctic and red foxes
on the North Slope. M.S. Thesis, Univ. Alaska,
Fairbanks. 125pp.
Edwards, M.E., and L.B. Brubaker. 1986. Late Quater-
nary vegetation history of the Fishhook bend area,
Porcupine River, Alaska. Can. J. Earth. Sci. 23:1765-
1773.
Elder, J.F. 1988. Factors affecting wetland retention of nu-
trients, metals, and organic materials. Pages 178-184
in J.A. Kusler and G. Brooks, eds. Proc. of the Na-
tional Wetland Symposium: Wetland Hydrology,
Chicago, 111., 1987. Assoc. State Wetland Managers
Tech. Rep. 6, Berne, N.Y.
Ellanna, L.J., and P.C. Wheeler. 1989. Wetlands and sub-
sistence-based economies in Alaska, U.S.A. Arct. and
Alpine Res. 21(4):329-340.
Ellison, L.N. 1975. Density of Alaskan spruce grouse
before and after fire. J. Wildl. Manage. 39(3):468-
471.
. 1976. Winter food selection by Alaskan spruce
grouse. J. Wildl. Manage. 40(2):205-213.
. 1989. Grouse. Alaska Dep. Fish Game Wildl.
Notebook Sen, Juneau. 2pp.
Elomaa, P.-L. 1987. Vertical distribution of copper and
manganese in the peat below vegetation types show-
ing mire-centre and mire-margin effects. Pages 107-
113 in C.D.A. Rubec and R.P. Overend, compilers.
Proc. Symposium '87 Wetlands/Peatlands,
Edmonton, Aha., 1987.
Engstrom, D.R. 1984. Lake development in the boreal
peatlands of southeastern Labrador, Canada. Arct.
and Alpine Res. 16(4):447-452.
Erskine, A.J. 1977. birds in boreal Canada: communities,
densities and adaptations. Can. Wildl. Serv. Rep.
Series No. 41. 73pp.
Eurola, S., K. Aapala, A. Kokko, and M. Nironen. 1991.
Mire type statistics in the bog and southern aapa mire
areas of Finland (60-66°N). Ann. Bot. Fenn 28" 15-
36.
, S. Hicks, and E. Kaakinen. 1984. Key to Finnish
mire types. Pages 11-117 in P.O. Moore, ed. Euro-
pean mires. Academic Press Inc. (London) Ltd.
Evans, K.E., G.P. Kershaw, and B.J. Gallinger. 1988.
Physical and chemical characteristics of the active
layer and near-surface permafrost in a disturbed ho-
mogeneous Picea mariana stand, Fort Norman,
N.W.T., Canada. Pages 568-573 in K. Senneset, ed!
736
-------
Literature Cited
Int. Conference on Permafrost (Fifth), Trondheim,
Norway, 1988. [Proc. Vol. 1] Tapir Publ., Trondheim.
Ewert, D. 1982. Birds in isolated bogs in central Michi-
gan. Am. Midi. Nat. 108(1):41-50.
Fechner, E.J., and H.F. Hemond. 1992. Methane transport
and oxidation in the unsaturated zone of a Sphagnum
peatland. Global Biogeochem. Cycles 6(l):33-44.
Fennessy, M.S., and W.J. Mitsch. 1989. Design and use of
wetlands for renovation of drainage from coal mines.
Pages 231-253 in W.J. Mitsch and S.E. J0rgensen,
eds. Ecological engineering: an introduction to
ecotechnology. John Wiley & Sons, Inc., New York.
Fenton, M.B., and R.M.R. Barclay. 1980. Myotis
lucifugus. Mamm. Species 142:1-8.
Ferrians, O.J., Jr. 1988. Pingos in Alaska: a review. Pages
734-739 in K. Senneset, ed. Int. Conference on Per-
mafrost (Fifth), Trondheim, Norway, 1988. [Proc.
Vol. 1] Tapir Publ., Trondheim.
FitzGibbon, J.E., and T. Dunne. 1981. Land surface and
lake storage during snowmelt runoff in a subarctic
drainage system. Arct. and Alpine Res. 13(3):277-
285.
Flanagan, P.W. 1986. Substrate quality influences on mi-
crobial activity and mineral availability in taiga for-
est floors. Pages 138-151 in K. Van Cleve, F.S.
Chapin, III, P.W. Flanagan, L.A. Viereck, and C.T.
Dymess, eds. Forest ecosystems in the Alaskan taiga.
Springer-Verlag, New York.
, and K. Van Cleve. 1983. Nutrient cycling in rela-
tion to decomposition and organic-matter quality in
taiga ecosystems. Can. J. For. Res. 13:795-817.
Florence, L.Z., and F.D. Cook. 1984. Asymbiotic ^-fix-
ing bacteria associated with three boreal conifers.
Can. J. For. Res. 14:595-597.
Flyger, V., and J.E. Gates. 1982. Pine squirrels. Pages
230-238 in J.A. Chapman and G.A. Feldhamer, eds.
Wild mammals of North American: biology, manage-
ment, and economics. Johns Hopkins Univ. Press,
Baltimore and London.
Foote, M.J. 1983. Classification, description, and dynam-
ics of plant communities after fire in the taiga of in-
terior Alaska. U.S. For. Serv. Pac. Northwest Res.
Stn. Res. Pap. PNW-307. 116pp.
Ford, J., and B.L. Bedford. 1987. The hydrology of Alas-
kan wetlands, U.S.A.: a review. Arct. and Alpine Res.
19(3):209-229.
Foster, D.R. 1984. Phytosociological description of the
forest vegetation of southeastern Labrador. Can. J.
Bot. 62:899-906.
, G.A. King, PH. Glaser, and H.E. Wright, Jr. 1983.
Origin of string patterns in boreal peatlands. Nature
306(5940):256-258.
Foster, N.W., I.K. Morrison, and H.S.D. Swan. 1986.
Growth response of a boreal black spruce stand to
fertilizer treatments. North. J. Appl. For. 3:142-144.
Fox, J.F., and J.P. Bryant. 1984. Instability of the snow-
shoe hare and woody plant interaction. Oecologia
63:128-135.
, and K. Van Cleve. 1983. Relationships between
cellulose decomposition, Jenny's k, forest-floor nitro-
gen, and soil temperature in Alaskan taiga forests.
Can. J. For. Res. 13(5):789-794.
Franzmann, A.W. 1981. Alces alces. Mamm. Species
154:1-7.
Freda, J., and W.A. Dunson. 1985. The effect of acidic
precipitation on amphibian breeding in temporary
ponds in Pennsylvania. U.S. Fish Wildl. Serv., East.
Energy Land Use Team, Biol. Rep. 80(40.22). 85pp.
Friedman, R.M., and C.B. DeWitt. 1979. Wetlands as car-
bon and nutrient reservoirs: a spatial, historical, and
societal perspective. Pages 175-185 in P.E. Greeson,
J.R. Clark, and J.E. Clark, eds. Wetland functions and
values: the state of our understanding. [Proc. natl.
symp. on wetlands, Lake Buena Vista, Fla., 1978]
Am. Water Resour. Assoc., Minneapolis, Minn.
Fugro Northwest, Inc. 1980. Municipality of Anchorage
wetlands hydrologic study. Rep. prepared by Fugro
Northwest, Inc., Anchorage, Alas. 36pp. + appendi-
ces.
Fuller, T.K., and L.B. Keith. 1981. Woodland caribou
population dynamics in northeastern Alberta. J.
Wildl. Manage. 45(1): 197-213.
Gabriel, H.W., and S.S. Talbot. 1984. Glossary of land-
scape & vegetation ecology for Alaska. U.S. Bur.
Land Manage. BLM-Alaska Tech. Rep. BLM/AK/
TR-84/10. 137pp.
Gabrielson, I.N., and F.C. Lincoln. 1959. The birds of
Alaska. The Stackpole Co., Harrisburg, Penn. and
Wildl. Manage. Inst., Washington, D.C. 922pp.
Gardner, C.L. 1985. The ecology of wolverines in
southcentral Alaska. M.S. Thesis, Univ. Alaska,
Fairbanks. 82pp.
Gasaway, W.C., R.D. Boertje, D.V. Grangaard, D.G.
Kelleyhouse, R.O. Stephenson, and D.G. Larsen.
1992. The role of predation in limiting moose at low
densities in Alaska and Yukon and implications for
conservation. Wildl. Monogr. 120:1-59.
, S.D. Dubois, and SJ. Harbo. 1985. Biases in aerial
transect surveys for moose during May and June. J.
Wildl. Manage. 49(3):777-784.
, R.O. Stephenson, J.L. Davis, P.E.K. Shepherd, and
O.E. Burris. 1983. Interrelationships of wolves, prey,
and man in interior Alaska. Wildl. Monogr. 84:1-50.
Gascon, C., and D. Planas. 1986. Spring pond water
chemistry and the reproduction of the wood frog,
Rana sylvatica. Can. J. Zool. 64:543-550.
Gehrels, J., and G. Mulamoottil. 1990. Hydrologic pro-
cesses in a southern Ontario wetland. Hydrobiologia
137
-------
Functional Profile of Black Spruce Wetlands in Alaska
208:221-234.
Gersper, P.L., V. Alexander, S.A. Barkley, R.J. Barsdate,
and PS. Flint. 1980. The soils and their nutrients.
Pages 219-254 in J. Brown, PC. Miller, L.L. Tieszen,
and F.L. Bunnell, eds. An arctic ecosystem: the
coastal tundra at Barrow, Alaska. Dowden,
Hutchinson & Ross, Inc., Stroudsburg, Penn.
Gibbs, J.P., J.R. Longcore, D.G. McAuley, and J.K.
Ringelman. 1991. Use of wetland habitats by selected
nongame water birds in Maine. U.S. Fish Wildl. Serv.
Fish Wildl. Res. 9. 57pp.
Gieck, R.E., Jr., and D.L. Kane. 1986. Hydrology of two
subarctic watersheds. Pages 283-291 in D.L. Kane,
ed. Proc. of the Symposium: Cold Regions Hydrol-
ogy, University of Alaska-Fairbanks. Am. Water
Resour. Assoc., Bethesda, Md.
Gilbert, B.S., and CJ. Krebs. 1991. Population dynamics
of Clethrionomys and Peromyscus in southwestern
Yukon 1973-1989. Holarct. Ecol. 14:250-259.
Gillespie, W.L., and S.C. Kendeigh. 1982. Breeding bird
populations in northern Manitoba. Can. Field-Nat.
96(3):272-281.
Glaser, P.H. 1987. The ecology of patterned boreal
peatlands of northern Minnesota: a community pro-
file. U.S. Fish Wildl. Serv. Biol. Rep. 85(7.14). 98pp.
, G.A. Wheeler, E. Gorham, and H.E. Wright, Jr.
1981. The patterned mires of the Red Lake Peatland,
northern Minnesota: vegetation, water chemistry and
landforms. J. Ecol. 69:575-599.
Glass, R.L. 1986a. Hydrologic conditions in the Klatt Bog
area, Anchorage, Alaska. U.S. Geol. Surv. Water-
Resour. Invest. Rep. 85-4330. 19pp.
. 1986&. Hydrologic conditions in Connors Bog
area, Anchorage, Alaska. U.S. Geol. Surv. Water-
Resour. Invest. Rep. 86-4044. 23pp.
Godfrey, W.E. 1979. The birds of Canada. Natl. Mus. Nat.
Sci., Natl. Mus. Can., Ottawa. 428pp.
Gordon, A.G. 1983. Nutrient cycling dynamics in differ-
ing spruce and mixedwood ecosystems in Ontario
and the effects of nutrient removals through harvest-
ing. Pages 97-118 in R.W. Wein, R.R. Riewe, and
I.R. Methven, eds. Resources and dynamics of the
Boreal Zone. [Proc. conf., Thunder Bay, Ontario,
1982] Assoc. Can. Univ. North. Stud.
Gore, A.J.P. 1983. Introduction. Pages 1-34 in A.J.P Gore,
ed. 4A. Mires: swamp, bog, fen, and moor - general
studies. Elsevier Sci. Publ. Co., Amsterdam.
Gorozhankina, S.M. 1991. Territorial and temporal laws
governing bog formation in the Enisei Valley. Soviet
J. Ecology 21(3):119-126.
Granhall, U., and A.V. Hofsten. 1976. Nitrogenase activ-
ity in relation to intracellular organisms in Sphagnum
mosses. Physiol. Plant. 36:88-94.
, and H. Selander. 1973. Nitrogen fixation in a sub-
arctic mire. Oikos 24:8-15.
Grant, K.P., and L.E. Licht. 1993. Acid tolerance of anu-
ran embryos and larvae from central Ontario. J.
Herpetol. 27(1): 1-6.
Grigal, D.F. 1979. Extractable soil nutrients and perma-
frost under adjacent forest types in interior Alaska.
Northwest Sci. 53(1):43-50.
1985. Impact of right-of-way construction on veg-
etation in the Red Lake Peatland, northern Minne-
sota. Environ. Manage. 9(5):449-454.
Grime, J.R, and J.M Anderson. 1986. Introduction. Pages
89-95 in K. Van Cleve, F.S. Chapin, III, P.W.
Flanagan, L.A. Viereck, and C.T. Dyrness, eds. For-
est ecosystems in the Alaskan taiga. Springer-Verlag,
New York.
Gruys, R.C. 1993. Autumn and winter movements and
sexual segregation of willow ptarmigan. Arctic
46(3):228-239).
Guthrie, R.D. 1990. Frozen fauna of the mammoth steppe:
the story of Blue Babe. Univ. Chicago Press, Chicago
and London. 323pp.
Haavisto, V.F., and V.H. Wearn. 1987. Intensifying for-
estry use of peatlands with drainage in Ontario. Pages
249-256 in C.D.A. Rubec and R.P. Overend, compil-
ers. Proc. Symposium '87 Wetlands/Peatlands,
Edmonton, Alta., 1987.
Hadley, R.S. 1969. The effects of season and temperature
on certain aspects of the physiology of the Alaskan
wood frog, Rana sylvatica. M.S. Thesis, Univ.
Alaska, College [Fairbanks], 42pp.
Haila, Y, I.K. Hanski, and S. Raivio. 1987. Breeding bird
distribution in fragmented coniferous taiga in south-
ern Finland. Ornis Fenn. 64(3):90-106.
Hakala, J.B. 1952. The life history and general ecology of
the beaver (Castor canadensis Kuhl) in interior
Alaska. M.S. Thesis, Univ. Alaska, Fairbanks. 181pp.
Hall, J.V., W.E. Prayer, and B.O. Wilen. 1994. Status of
Alaska wetlands. U.S. Fish Wildl. Serv. Alaska Reg.,
Anchorage. 32pp.
Hamerstrom, F. 1986. Harrier, hawk of the marshes.
Smithsonian Inst. Press, Washington, D.C. 171pp.
Hamilton, J.D., C.A. Kelly, J.W.M. Rudd, R.H. Hesslein,
and N.T. Roulet. 1994. Flux to the atmosphere of
CH4 and CO2 from wetland ponds on the Hudson
Bay lowlands (HBLs). J. Geophys. Res.
99(D1): 1495-1520.
Hamilton, T.D., T.A. Ager, and S.W. Robinson. 1983. Late
Holocene ice wedges near Fairbanks, Alaska, U.S.A.:
environmental setting and history of growth. Arct.
and Alpine Res. 15(2):157-168.
Hansen, H.A., P.E.K. Shepherd, J.G. King, and W.A.
Troyer. 1971. The trumpeter swan in Alaska. Wildl.
Monogr. 26:1-83.
Harkonen, K. 1987. Classifying peatlands for forest drain-
138
-------
Literature Cited
age and growth in Alberta. Pages 465-471 in C.D.A.
Rubec and R.P. Overend, compilers. Proc. Sympo-
sium ' 87 Wetlands/Peatlands, Edmonton, Alta., 1987.
Harlow, W.M., and E.S. Harrar. 1968. Textbook of den-
drology. Fifth ed. McGraw-Hill, Inc., New York.
512pp.
Harris, S.A. 1987. Altitude trends in permafrost active
layer thickness, Kluane Lake, Yukon Territory. Arc-
tic 40(3):179-183.
Harrison, DJ. 1983. Denning ecology, movements, and
dispersal of coyotes in eastern Maine. M.S. Thesis,
Univ. Maine, Orono. 48pp.
Hatler, D.F. 1967. Some aspects in the ecology of the
black bear (Ursus americanus) in interior Alaska.
M.S. Thesis, Univ. Alaska, Fairbanks. 110pp.
. 1972. Food habits of black bears in interior
Alaska. Can. Field-Nat. 86:17-31.
Haugen, R.K., S.I. Outcalt, and J.C. Hade. 1983. Rela-
tionships between estimated mean annual air and
permafrost temperatures in north-central Alaska.
Pages 462-467 in Int. Conference on Permafrost
(Fourth), Fairbanks, Alas., 1983. [Proc.] Natl. Acad.
Press, Washington, D.C.
, C.W. Slaughter, K.E. Howe, and S.L. Dingman.
1982. Hydrology and climatology of the Caribou-
Poker Creeks Research Watershed, Alaska. U.S.
Army Cold Reg. Res. Eng. Lab. Rep. 82-26. 34pp.
Hayward, G.D., PH. Hayward, and E.G. Carton. 1993.
Ecology of boreal owls in the northern Rocky Moun-
tains, USA. Wildl. Monogr. 124:1-59.
Hechtel, J.L. 1991. Population dynamics of black bear
populations, Fort Wainwright, Alaska. Final Rep. to
U.S. Army [Nat. Res. Rep #91-2] by Alaska Dep.
Fish Game, Fairbanks. 62pp.
Heebner, O.K. 1982. The numerical analysis of vegetation
plots in Denali National Park and Preserve. M.S.
Thesis, Univ. Alaska, Fairbanks. 243pp.
Heglund, P.J. 1988. Relations between waterbird use and
the limnologic characteristics of wetlands on Yukon
Flats National Wildlife Refuge, Alaska. M.S. Thesis,
Univ. Missouri-Columbia. 179pp.
. 1992. Patterns of wetland use among aquatic birds
in the interior boreal forest region of Alaska. Ph.D.
Diss., Univ. Missouri-Columbia. 394pp.
Heilman, P.E. .1966. Change in distribution and availabil-
ity of nitrogen with forest succession on north slopes
in interior Alaska. Ecology 47(5):825-831.
. 1968. Relationship of availability of phosphorus
and cations to forest succession and bog formation in
interior Alaska. Ecology 49(2):331-336.
Heinselman, M.L. 1963. Forest sites, bog processes, and
peatland types in the Glacial Lake Agassiz Region,
Minnesota. Ecol. Monogr. 33(4):327-374.
. 1970. Landscape evolution, peatland types, and
the environment in the Lake Agassiz Peatlands Natu-
ral Area, Minnesota. Ecol. Monogr. 40(2):235-261.
Helm, D.J, J.D. McKendrick, and W.B. Collins. 1987.
Fertilizer effects on annual grass in wet sedge-grass
vegetation site, Susitna Basin, Alaska, U.S.A. Arct.
and Alpine Res. 19(l):29-34.
Hemming, I.E. 1971. The distribution and movement pat-
terns of caribou in Alaska. Alaska Dep. Fish Game,
Game Tech. Bull. No. 1. 60pp.
Henderson, E.P. 1968. Patterned ground in southeastern
Newfoundland. Can. J. Earth Sci. 5:1443-1453.
Herreid, C.F., II, and S. Kinney. 1967. Temperature and
development of the wood frog, Rana sylvatica, in
Alaska. Ecology 48(4):579-590.
Hilgert, J.W., and C.W. Slaughter. 1983. Water quality and
streamflow in the Caribou-Poker Creeks Research
Watershed, Central Alaska, 1978. U.S. For. Serv. Pac.
Northwest For. Range Exp. Stn. Res. Note PNW-405.
36pp.
, and . 1987. Water quality and streamflow in
the Caribou-Poker Creeks Research Watershed, Cen-
tral Alaska, 1979. U.S. For. Serv. Pac. Northwest Res.
Stn. Res. Note PNW-RN-463. 34pp.
Hill, E.P. 1982. Beaver. Pages 256-281 in J.A. Chapman
and G.A. Feldhamer, eds. Wild mammals of North
American: biology, management, and economics.
Johns Hopkins Univ. Press, Baltimore and London.
Hillman, G.R. 1987. Improving wetlands for forestry in
Alberta. Pages 241-247 in C.D.A. Rubec and R.P.
Overend, compilers. Proc. Symposium '87 Wetlands/
Peatlands, Edmonton, Alta., 1987.
Hobbie, I.E. 1984. The ecology of tundra ponds of the
Arctic Coastal Plain: a community profile. U.S. Fish
Wildl. Serv. FWS/OBS-83/25. 52pp.
Hodge, R.P. 1976. Amphibian? and reptiles in Alaska, the
Yukon, and Northwest Territories. Alaska Northwest
Publ. Co., Anchorage, Alas. 89pp.
Hogan, M., and G.F. Tande. 1983. Vegetation types and
bird use of Anchorage wetlands. U.S. Fish Wildl.
Serv., Spec. Stud., Anchorage, Alas. 134pp.
Hollis, G.E., andT.A. Jones. 1991. Europe and the Medi-
terranean Basin. Pages 27-56 in M. Finlayson and M.
Moser, eds. Wetlands. Int. Waterfowl and Wetlands
Res. Bur. and Facts on File Ltd., Oxford, U.K.
Holmes, G.W., H.L. Foster, and D.M. Hopkins. 1963.
Distribution and age of pingos of interior Alaska.
Pages 88-93 in Int. Conference on Permafrost,
Lafayette, Ind., 1963. [Proc.] Natl. Acad. Sci. Natl.
Res. Counc. Publ. No. 1287, Washington, D.C.
Holmes, K. 1990. Ship to shore. Alaska Business 6(3):44-
54.
Horn, J.L. 1986. Investigations into some of the major
controls on the productivity of a black spruce (Picea
mariana [Mill.] B.S.P.) forest ecosystem in the inte-
139
-------
Functional Profile of Black Spruce Wetlands in Alaska
rior of Alaska. Ph.D. Thesis, Univ. Alaska, Fairbanks.
145pp.
, and W.C. Oechel. 1983. The photosynthetic capac-
ity, nutrient content, and nutrient use efficiency of
different needle age-classes of black spruce (Picea
mariand) found in interior Alaska. Can. J. For. Res.
13:834-839.
Hopkins, D.M., T.N.V. Karlstrom, R.F. Black, J.R. Will-
iams, T.L. Pewe, A.T. Fernold, and E.H. Muller.
1955. Permafrost and ground water in Alaska. U.S.
Geol. Surv. Prof. Pap. 264-F. 146pp.
, and J.G. Kidd. 1988. Thaw lake sediments and
sedimentary environments. Pages 790-795 in K.
Senneset, ed. Int. Conference on Permafrost (Fifth),
Trondheim, Norway, 1988. [Proc. Vol. 1] Tapir Publ.,
Trondheim.
Houston, C.S. 1987. Nearly synchronous cycles of the
great horned owl and snowshoe hare in
Saskatchewan. Pages 56-58 in R.W. Nero, R.J. Clark,
R.J. Knapton, and R.H. Hamre, eds. Biology and
conservation of northern forest owls: symposium
proceedings, Winnipeg, Manit., 1987. U.S. For. Serv.
Rocky Mt. For. Range Exp. Stn. Gen. Tech. Rep.
RM-142.
Huck, R.W., and S.E. Rawlinson. 1982. Peat resource in-
ventory of south-central Alaska, a data report. Alaska
Div. Geol. Geophys. Surv. Alaska Open File Rep.
AOF-150. 18pp. + appendices + 1 plate.
Hughes, O.L., C.R. Harington, J.A. Janssens, J.V.
Matthews, Jr., R.E. Morlan, N.W. Rutter, and C.E.
Schweger. 1981. Upper Pleistocene stratigraphy, pa-
leoecology, and archaeology of the northern Yukon
interior, eastern Beringia: 1. Bonnet Plume Basin.
Arctic 34(4):329-365.
Humphrey, S.R. 1982. Bats. Pages 52-70 in J.A. Chapman
and G.A. Feldhamer, eds. Wild mammals of North
American: biology, management, and economics.
Johns Hopkins Univ. Press, Baltimore and London.
Hunter, R.E., J.A. Crawford, and R.E. Ambrose. 1988.
Prey selection by peregrine falcons during the nest-
ling stage. J. Wild). Manage. 52(4):730-736.
Ingram, H.A.P. 1983. Hydrology. Pages 67-158 in A.J.P.
Gore, ed. 4A. Mires: swamp, bog, fen, and moor -
general studies. Elsevier Sci. Publ. Co., Amsterdam.
Jarrell, G.H., S.O. MacDonald, and J.A. Cook. 1994.
Checklist to the Recent mammals of Alaska. Univ.
Alaska Mus., Fairbanks.
Jasieniuk, M.A., and E.A. Johnson. 1982. Peatland veg-
etation organization and dynamics in the western
subarctic, Northwest Territories, Canada. Can. J. Bot.
60:2581-2593.
Jayaweera, K.O.L.F., G. Wendler, and T. Ohtake. 1973.
Low cloud cover and the winter temperature of
Fairbanks. Pages 316-322 in G. Weller and S.A.
Bowling, eds. Climate of the Arctic. [Alaska Sci.
Conf. (Twenty-Fourth), Fairbanks, Alas., 1973]
Geophys. Inst., Univ. Alaska, Fairbanks.
Jenkins, S.H., and P.E. Busher. 1979. Castor canadensis.
Mamm. Species 120:1-8.
Je'nkins, T.F., L.A. Johnson, C.M. Collins, and T.T.
McFadden. 1978. The physical, chemical and bio-
logical effects of crude oil spills on black spruce for-
est, interior Alaska. Arctic 31(3):305-323.
Johnsgard, PA. 1988. North American owls: biology and
natural history. Smithsonian Inst. Press, Washington
and London. 295pp.
Johnson, L.A, E.B. Sparrow, T.F. Jenkins, C.M. Collins,
C.V. Davenport, and T.T. McFadden. 1980. The fate
and effects of crude oil spilled on subarctic perma-
frost terrain in interior Alaska. U.S. Army Cold Reg.
Res. Eng. Lab. Rep. 80-29. 77pp.
Johnson, L.C. 1987. Macrostructure of Sphagnum peat as
an indication of bog processes. Pages 61-69 in
C.D.A. Rubec and R.P. Overend, compilers. Proc.
Symposium '87 Wetlands/Peatlands, Edmonton,
Alta., 1987.
Johnson, M.L., and S. Johnson. 1982. Voles. Pages 326-
354 in J.A. Chapman and G.A. Feldhamer, eds. Wild
mammals of North American: biology, management,
and economics. Johns Hopkins Univ. Press, Balti-
more and London.
Johnson, P.L., and T.C. Vogel. 1966. Vegetation of the
Yukon Flats Region, Alaska. U.S. Army Cold Reg.
Res. Eng. Lab. Res. Rep. 209. 53pp.
Johnson, S.R., and D.R. Herter. Birds of the Beaufort Sea.
BP Exploration (Alaska) Inc., Anchorage, Alas.
372pp.
Johnston, W.F. 1977. Manager's handbook for black
spruce in the north central States. U.S. For. Serv.
North Central For. Exp. Stn. Gen. Tech. Rep. NC-34.
18pp.
Jones, E.T. 1987. Observations of the northern hawk owl
in Alberta. Pages 149-151 in R.W. Nero, R.J. Clark,
R.J. Knapton, and R.H. Hamre, eds. Biology and
conservation of northern forest owls: symposium
proceedings, Winnipeg, Manit., 1987. U.S. For. Serv.
Rocky Mt. For. Range Exp. Stn. Gen. Tech. Rep.
RM-142.
Jones, R.D., and J.A. Amador. 1992. Removal of total
phosphorus and phosphate by peat soils of the Florida
Everglades. Can. J. Fish. Aquatic Sci. 49:577-583.
J0rgensen, S.E., and W.J. Mitsch. 1989. Classification and
examples of ecological engineering. Pages 13-19 in
W.J. Mitsch and S.E. J0rgensen, eds. Ecological en-
gineering: an introduction to ecotechnology. John
Wiley & Sons, Inc., New York.
Jorgenson, M.T., and R.A. Kreig. 1988. A model for map-
ping permafrost distribution based on landscape com-
140
-------
Literature Cited
ponent maps and climatic variables. Pages 176-182
in K. Senneset, ed. Int. Conference on Permafrost
(Fifth), Trondheim, Norway, 1988. [Proc. Vol. 1]
Tapir Publ., Trondheim.
Kadlec, R.H. 1979. Wetlands for tertiary treatment. Pages
490-504 in P.E. Greeson, J.R. Clark, and I.E. Clark,
eds. Wetland functions and values: the state of our
understanding. [Proc. natl. symp. on wetlands, Lake
Buena Vista, Fla., 1978] Am. Water Resour. Assoc.,
Minneapolis, Minn.
. 1987. The use of peatlands for wastewater treat-
ment. Pages 213-218 in C.D.A. Rubec and R.P.
Overend, compilers. Proc. Symposium '87 Wetlands/
Peatlands, Edmonton, Alia., 1987.
. 1988. Wetland hydrology and water pollution con-
trol functions. Pages 168-173 in J.A. Kusler and G.
Brooks, eds. Proc. of the National Wetland Sympo-
sium: Wetland Hydrology, Chicago, 111., 1987. Assoc.
State Wetland Managers Tech. Rep. 6, Berne, N.Y.
, and J.A. Kadlec. 1979. Wetlands and water qual-
ity (theme paper). Pages 436-456 in P.E. Greeson,
J.R. Clark, and J.E. Clark, eds. Wetland functions and
values: the state of our understanding. [Proc. natl.
symp. on wetlands, Lake Buena Vista, Fla., 1978]
Am. Water Resour. Assoc., Minneapolis, Minn.
Kane, D.L. 1980. Snowmelt infiltration into seasonally
frozen soils. Cold Reg. Sci. Tech. 3:153-161.
, S.R. Bredthauer, and J. Stein. 1981. Subarctic
snowmelt runoff generation. Pages 591-601 in Proc.
Special Conference on the Northern Community: a
search for a quality environment, Seattle, Wash.,
1981.Am.Soc. Civil Eng.
, R.F. Carlson, and C.E. Bowers. 1973. Groundwa-
ter pore pressures adjacent to subarctic streams.
Pages 453-458 in Int. Conference on Permafrost
(Second), Yakutsk, U.S.S.R., 1973. [North Am.
Contrib.] Natl. Acad. Sci., Washington, D.C.
, J.D. Fox, R.D. Seifert, and G.S. Taylor. 1978.
Snowmelt infiltration and movement in frozen soils.
Pages 200-206 in Int. Conference on Permafrost
(Third), Edmonton, Alta., Can., 1978. [Proc. Vol. 1]
Natl. Res. Counc. Can., Ottawa.
, and C.W. Slaughter. 1973. Recharge of a central
Alaska lake by subpermafrost groundwater. Pages
458-462 in Int. Conference on Permafrost (Second),
Yakutsk, U.S.S.R., 1973. [North Am. Contrib.] Natl.
Acad. Sci., Washington, D.C.
, and J. Stein. 1983. Field evidence of groundwater
recharge in interior Alaska. Pages 572-577 in Int.
Conference on Permafrost (Fourth), Fairbanks, Alas.,
1983. [Final Proc.] Natl. Acad. Press, Washington,
D.C.
Kangas, P.C. 1990. An energy theory of landscape for
classifying wetlands. Pages 15-23 inA.E. Lugo, S.
Brown, and M. Brinson, eds. 15. Forested wetlands.
Elsevier Sci. Publ. Co., Amsterdam.
Karns, D.R. 1992. Effects of acidic bog habitats on am-
phibian reproduction in a northern Minnesota
peatland. J. Herpetol. 26(4):401-412.
Keith, L.B. n.d. Snowshoe hare. Can. Wildl. Serv. 3pp.
, J.R. Gary, O.J.Rongstad, and M.C. Brittingham.
1984. Demography and ecology of a declining snow-
shoe hare population. Wildl. Monogr. 90:1-43.
Kelly, D.G. 1978. Population density, territoriality, and
foraging ecology of red squirrels (Tamiasciurus
hudsonicus) in black and white spruce forests of in-
terior Alaska. M.S. Thesis, Univ. Alaska, Fairbanks.
123pp.
Kelsall, J.P. 1968. The migratory barren-ground caribou
of Canada. Dep. Indian Aff. North. Dev. and Can.
Wildl. Serv., Ottawa. 340pp. + maps
Kent, R.L. 1987. Wetlands wastewater treatment - Blue
Quills School, St. Paul, Alberta. Pages 233-240 in
C.D.A. Rubec and R.P. Overend, compilers. Proc.
Symposium '87 Wetlands/Peatlands, Edmonton,
Alta., 1987.
Kershaw, G.P., and D. Gill. 1979. Growth and decay of
palsas and peat plateaus in the Macmillan Pass-
Tsichu River area, Northwest Territories, Canada.
Can. J. Earth Sci. 16:1362-1374.
Kertell, K. 1982. Reproductive biology of hawk owls
(Surnia ululd) in Denali National Park, Alaska. M.S.
Thesis, Humboldt State Univ., Arcata, Calif. 63pp.
Kessel, B. 1965. Breeding dates ofRana sylvatica at Col-
lege, Alaska. Ecology 46(1-2):206-208.
. 1984. Migration of sandhill cranes, Grus
canadensis, in east-central Alaska, with routes
through Alaska and western Canada. Can. Field-Nat.
98(3):279-292.
, S.O. MacDonald, D.D. Gibson, B.A. Cooper, and
B.A. Anderson. 1982. Alaska Power Authority
Susitna Hydroelectric Project, Environmental Stud-
ies Phase 1 Final Report, Subtask 7.11, Birds and
Non-Game Mammals (Baseline Studies). Univ.
Alaska Museum, Fairbanks. 137pp.
, and G.B. Schaller. 1960. Birds of the upper
Sheenjek Valley, northeastern Alaska. Biol. Pap.
Univ. Alaska, No. 4., Fairbanks. 59pp.
, and H.K. Springer. 1966. Recent data on status of
some interior Alaska birds. Condor 68:185-195.
Kessel-Taylor, I., and J.M. Anderson. 1987. Preliminary
rating of wetland potential to reduce incoming acidic
deposition. Pages 317-323 in C.D.A. Rubec and R.P.
Overend, compilers. Proc. Symposium '87 Wetlands/
Peatlands, Edmonton, Alta., 1987.
Kimmins, J.P, and R.W. Wein. 1986. Introduction. Pages
3-8 in K. Van Cleve, F.S. Chapin, III, P.W. Flanagan,
L.A. Viereck, and C.T. Dyrness, eds. Forest ecosys-
141
-------
Functional Profile of Black Spruce Wetlands in Alaska
terns in the Alaskan taiga. Springer-Verlag, New
York.
King, C.M. 1983. Mustela erminea. Mamm. Species
195:1-8.
Kirton, M.P. 1974. Fall movements and hibernation of the
wood frog, Rana sylvatica, in interior Alaska. M.S.
Thesis, Univ. Alaska, Fairbanks. 57pp.
Klinger, L.F., P.R. Zimmerman, J.P. Greenberg, L.E.
Heidt, and A.B. Guenther. 1994. Carbon trace gas
fluxes along a successional gradient in the Hudson
Bay lowland. J. Geophys. Res. 99(D1):1469-1494.
Koehler, G.M., and M.G. Hornocker. 1977. Fire effects on
marten habitat in the Selway-Bitterroot wilderness. J.
Wildl. Manage. 41(3):500-505.
Korpimaki, E. 1986. Niche relationships and life-history
tactics of three sympatric Strix owl species in Fin-
land. Ornis Scand. 17(2):126-132.
. 1987. Prey caching of breeding Tengmalm's owls
Aegolius funereus as a buffer against temporary food
shortage. Ibis 129:499-510.
, and K. Norrdahl. 1989. Predation of Tengmalm's
owls: numerical responses, functional responses and
dampening impact on population fluctuations of
microtines. Oikos 54:154-164.
Kortelainen, P., and J. Mannio. 1988. Natural and anthro-
pogenic acidity sources for Finnish lakes. Water, Air,
and Soil Pollut. 42(3-4):341-352.
Koutz, F.R., and C.W. Slaughter. 1973. Equivalent lati-
tude (potential insolation) and a permafrost environ-
ment: Caribou-Poker Creeks Research Watershed
interior Alaska. U.S. Army Cold Reg. Res. Eng. Lab.
Tech. Note. 33pp.
Kraus, M.L. 1988. Wetlands: toxicant sinks or reservoirs?
Pages 192-196 in J.A. Kusler and G. Brooks, eds.
Proc. of the National Wetland Symposium: Wetland
Hydrology, Chicago, 111., 1987. Assoc. State Wetland
Managers Tech. Rep. 6, Berne, N.Y.
Krebs, C.J. 1972. Ecology: the experimental analysis of
distribution and abundance. Harper & Row, Publ.,
Inc., New York. 694pp.
, and I. Wingate. 1985. Population fluctuations in
the small mammals of the Kluane Region, Yukon
Territory. Can. Field-Nat. 99(1):51-61.
Kron, T.M. 1975. Late winter bird populations in subarc-
tic taiga forest near Fairbanks, Alaska. Auk
92(2):390-393.
Kroodsma, D.E. 1979. Habitat values for nongame wet-
land birds. Pages 320-329 in P.E. Greeson, J.R.
Clark, and I.E. Clark, eds. Wetland functions and
values: the state of our understanding. [Proc. natl.
symp. on wetlands, Lake Buena Vista, Fla., 1978]
Am. Water Resour. Assoc., Minneapolis, Minn.
Kummerow, J., B.A. Ellis, S. Kummerow, and F.S.
Chapin, III. 1983. Spring growth of shoots and roots
in shrubs of an Alaskan muskeg. Am. J. Bot.
70(10):1509-1515.
Lacki, M.J., W.T. Peneston, K.B. Adams, F.D. Vogt, and
J.C. Houppert. 1990. Summer foraging patterns and
diet selection of muskrats inhabiting a fen wetland.
Can. J.Zool. 68:1163-1167.
Lan, C., G. Chen, L. Li, and M.H. Wong. 1992. Use of
cattails in treating wastewater from a Pb/Zn mine.
Environ. Manage. 16(1):75-80.
Lanctot, R.B., and P.X. Quang. 1992. Density of loons in
central Alaska. Condor 94:282-286.
Langford, A.O., and F.C. Fehsenfeld. 1992. Natural veg-
etation as a source or sink for atmospheric ammonia:
a case study. Science 255(5044):581-583.
LaPerriere, J.D. 1983. Alkalinity, discharge, average ve-
locity, and invertebrate drift concentrations in subarc-
tic Alaskan streams. J. Freshwater Ecol.
Laprise, D., and S. Payette. 1988. Recent evolution of
palsa bogs in subarctic Quebec: cartographic and
dendrochronological analysis. Can. J. Bot.
66(ll):2217-2227.
Larsen, J.A. 1982. Ecology of the northern lowland bogs
and conifer forests. Academic Press, New York.
307pp.
Larson, J.S. 1991. North America. Pages 57-84 in M.
Finlayson and M. Moser, eds. Wetlands. Int. Water-
fowl and Wetlands Res. Bur. and Facts on File Ltd.,
Oxford, U.K.
_ , P.R. Adamus, and E.J. Clairain, Jr. 1988. Func-
tional assessment of freshwater wetlands: a manual
and training outline. Int. Union Conserv. Nat. Nat.
Resour. 78pp.
Lavoie, C., and S. Payette. 1992. Black spruce growth
forms as a record of changing winter environment at
treeline, Quebec, Canada. Arct. and Alpine Res.
24(l):40-49.
Lawrence, W.T, and W.C. Oechel. 1983a. Effects of soil
temperature on the carbon exchange of taiga seed-
lings. I. Root respiration. Can. J. For. Res. 13:840-
849.
_ , and _ . 19836. Effects of soil temperature on
the carbon exchange of taiga seedlings. II. Photosyn-
thesis, respiration, and conductance. Can. J. For. Res.
13:850-859.
Lee, J., I.R. Jonasson, and W.D. Goodfellow. 1984. Metal
accumulation by bryophytes in some zinc-rich blan-
ket bogs, Selwyn Mountains, Yukon Territory. Can. J.
Bot. 62:722-728.
Lee, P.G., R.A. Ellis, and PL. Achuff. 1982. Vegetation
and flora of the Caribou Mountains, Alberta. Can.
Field-Nat. 96(4):389-408.
Lee, R. 1980. Forest hydrology. Columbia Univ. Press,
New York. 349pp.
142
-------
Literature Cited
Legere, A., and S. Payette. 1981. Ecology of a black
spruce (Picea mariana) clonal population in the
Hemiarctic Zone, northern Quebec. Arct. and Alpine
Res. 13(3):261-276.
Lein, M.R., and P.C. Boxall. 1979. Interactions between
snowy and short-eared owls in winter. Can. Field-
Nat. 93(4):411-414.
Lensink, C.J. 1954. Occurrence of (Microtus
xanthognathus) in Alaska. J. Mammal. 35:259.
[Abstr. in Magoun and Johnson 1991]
Levan, M.A., and S.J. Riha. 1986. The precipitation of
black oxide coatings on flooded conifer roots of low
internal porosity. Plant and Soil 95:33-42.
Li, Y., and J.M. Glime. 1991. Growth response of two
Sphagnum species to photoperiod. Can. J. Bot.
69:2643-2646.
Lieffers, V.J., and R.L. Rothwell. 1987. Effects of drain-
age on substrate temperature and phenology of some
trees and shrubs in an Alberta peatland. Can. J. For.
Res. 17:97-104.
Ling, R.W., J.P. VanAmberg, and J.K. Werner. 1986. Pond
acidity and its relationship to larval development of
Ambystoma maculatium and Rana sylvatica in upper
Michigan. J. Herpetol. 20(2):230-236.
Linscombe, G., N. Kinler, and R.J. Aulerich. 1982. Mink.
Pages 629-643 in J.A. Chapman and G.A.
Feldhamer, eds. Wild mammals of North American:
biology, management, and economics. Johns
Hopkins Univ. Press, Baltimore and London.
Livingston, R.J., and O.L. Loucks. 1979. Productivity,
trophic interactions, and food-web relationships in
wetlands and associated systems (theme paper).
Pages 101-119 in P.E. Greeson, J.R. Clark, and J.E.
Clark, eds. Wetland functions and values: the state of
our understanding. [Proc. natl. symp. on wetlands,
Lake Buena Vista, Fla., 1978] Am. Water Resour.
Assoc., Minneapolis, Minn.
Long, C.A. 1974. Microsorex hoyi and Microsorex
thompsoni. Mamm. Species 33:1-4.
Lowe, E.F., L.E. Battoe, D.L. Stites, and M.F. Coveney.
1992. Paniculate phosphorus removal via wetland
filtration: an examination of potential for hyper-
trophic lake restoration. Environ. Manage. 16(1):67-
74.
Lugo, A.E. 1990. Introduction. Pages 1-14 in A.E. Lugo,
S. Brown, and M. Brinson, eds. 15. Forested wet-
lands. Elsevier Sci. Publ. Co., Amsterdam.
, M.M. Brinson, and S. Brown. 1990. Synthesis and
search for paradigms in wetland ecology. Pages 447-
460 in A.E. Lugo, S. Brown, and M. Brinson, eds. 15.
Forested wetlands. Elsevier Sci. Publ. Co.,
Amsterdam.
, S. Brown, and M.M. Brinson. 1990. Concepts in
wetland ecology. Pages 53-85 in A.E. Lugo, S.
Brown, and M. Brinson, eds. 15. Forested wetlands.
Elsevier Sci. Publ. Co., Amsterdam.
Luken, J.O. 1985. Zonation of Sphagnum mosses: inter-
actions among shoot growth, growth form, and wa-
ter balance. Bryologist 88(4):374-379.
Ma, S., and J. Yan. 1989. Ecological engineering for treat-
ment and utilization of wastewater. Pages 185-217 in
W.J. Mitsch and S.E. J0rgensen, eds. Ecological en-
gineering: an introduction to ecotechnology. John
Wiley & Sons, Inc., New York.
MacDonald, G.M. 1983. Holocene vegetation history of
the upper Natla River area, Northwest Territories,
Canada. Arct. and Alpine Res. 15(2): 169-180.
MacLean, S.F., Jr. 1980. The detritus-based trophic sys-
tem. Pages 411-457 in J. Brown, P.C. Miller, L.L.
Tieszen, and F.L. Bunnell, eds. An arctic ecosystem:
the coastal tundra at Barrow, Alaska. Dowden,
Hutchinson & Ross, Inc., Stroudsburg, Penn.
Magnusson, B., and J.M. Stewart. 1987. Effects of distur-
bances along hydroelectrical transmission corridors
through peallands in northern Manitoba, Canada.
Arct. and Alpine Res. 19(4):470-478.
Magoun, A.J. 1985. Population characteristics, ecology,
and management of wolverines in northwestern
Alaska. Ph.D. Thesis, Univ. Alaska, Fairbanks.
197pp.
, and W.N. Johnson. 1991. Wildfire and furbearers
in the boreal forest with emphasis on marten, lynx,
and their prey: an annotated bibliography. U.S. Fish
Wildl. Serv., Koyukuk/Nowitna Refuge Complex,
Galena, Alas. 305pp.
, and D.J. Vemam. 1986. An evaluation of the Bear
Creek burn as marten (Martes americana) habitat in
interior Alaska. Spec. Proj. Coop. Agreement AK-
950-CAH-O, Bur. Land Manage, and Alaska Dep.
Fish Game, Fairbanks. 58pp. + appendices. [Abstr. in
Magoun and Johnson 1991]
Mahendrappa, M.K. 1986. Abilities of organic horizons
under some eastern Canadian forest stands to alter the
acidity of rainwater. Can. J. For. Res. 16:18-22.
Malmer, N. 1988. Patterns in the growth and the accu-
mulation of inorganic constituents in the Sphagnum
cover on ombrotrophic bogs in Scandinavia. Oikos
53(1):105-120.
Maltby, E. 1986. Waterlogged wealth: why waste the
world's wet places? Int. Inst. for Environ, and Dev.,
London and Washington, D.C. 200pp.
. 1991. Wetlands and their values. Pages 8-26 in M.
Finlayson and M. Moser, eds. Wetlands. Int. Water-
fowl and Wetlands Res. Bur. and Facts on File Ltd.,
Oxford, U.K.
Manuwal, D.A. 1978. Avian diversity and habitat selec-
tion in the Noatak Valley, Brooks Range, Alaska.
Murrelet 59:42-58.
143
-------
Functional Profile of Black Spruce Wetlands in Alaska
Manville, R.H., and S.P. Young. 1965. Distribution of
Alaskan mammals. U.S. Fish Wildl. Serv. Bur. Sport
Fish. Wildl.Circ. 211.74pp.
Marchand, P.J. 1987. Life in the cold. Univ. Press of New
England, Hanover, N.H. 176pp.
Marcotte, J.R. 1991. Wild fish and game harvest and use
by residents of five upper Xanana communities,
Alaska, 1987-88. Alaska Dep. Fish Game Div. Sub-
sistence Tech. Pap. No. 168. 200pp.
Martell, A.M. 1984. Changes in small mammal commu-
nities after fire in northcentral Ontario. Can. Field-
Nat. 98(2):223-226.
Martin, A.M. 1983. Bioconversion of peat: utilization of
peat extracts as a fermentation substrate. Pages 370-
377 in R.W. Wein, R.R. Riewe, and I.R. Methven,
eds. Resources and dynamics of the Boreal Zone.
[Proc. conf., Thunder Bay, Ontario, 1982] Assoc.
Can. Univ. North. Stud.
Martin, P.D., R.E. Spangler, and L.K. Bright. 1995. Bird
use of habitats in the Badger Watershed, near
Fairbanks, Alaska. U.S. Fish Wildl. Serv. Ecol. Serv.,
Fairbanks, Alas., Tech. Rep. NAES-TR-95-1. 38pp.
+ appendices.
Masing, V. 1984. Estonian bogs: plant cover, succession
and classification. Pages 119-148 in P.O. Moore, ed.
European mires. Academic Press Inc., London.
Mason, C.F., and V. Standen. 1983. Aspects of secondary
production. Pages 367-382 in A.J.P. Gore, ed. 4A.
Mires: swamp, bog, fen, and moor - general studies.
Elsevier Sci. Publ. Co., Amsterdam.
Matthews, E., and I. Fung. 1987. Methane emission from
natural wetlands: global distribution, area, and envi-
ronmental characteristics of sources. Global
Biogeochem. Cycles l(l):61-86.
Matthews, J.V., Jr. 1970. Quaternary environmental his-
tory of interior Alaska: pollen samples from organic
colluvium and peats. Arct. and Alpine Res. 2(4):241-
251.
Maxwell, J., and R. Costanza. 1989. An ecological eco-
nomics for ecological engineering. Pages 57-77 in
W.J. Mitsch and S.E. J0rgensen, eds. Ecological en-
gineering: an introduction to ecotechnology. John
Wiley & Sons, Inc., New York.
McCarthy, T.M. 1989. Food habits of brown bears on
northern Admiralty Island, Southeast Alaska. M.S.
Thesis, Univ. Alaska, Fairbanks. 84pp.
McCord, C.M., and J.E. Cardoza. 1982. Bobcat and lynx.
Pages 728-766 in J.A. Chapman and G.A.
Feldhamer, eds. Wild mammals of North American:
biology, management, and economics. Johns
Hopkins Univ. Press, Baltimore and London.
McGowan, J.D. 1975. Distribution, density and produc-
tivity of goshawks in interior Alaska. Alaska Dep.
Fish and Game Final Rep., Fed. Aid Wildl. Restor.
Proj. W-17-3,W-17-4,W-17-5, and W-17-6, Job No.
10.6R. 31pp. + appendices.
McKelvey, R.W., M.C. Dennington, and D. Mossop.
1983. The status and distribution of trumpeter swans
(Cygnus buccinator) in the Yukon. Arctic 36(1):76-
81.
McNamara, J.P., D.I. Siegel, P.H. Glaser, and R.M. Beck.
1992. Hydrogeologic controls on peatland develop-
ment in the Malloryville Wetland, New York (USA).
J. Hydrol. 140:279-296.
Mech, L.D. 1974. Cam's lupus. Mamm. Species 37:1-6.
Meehan, R.H., and R.J. Ritchie. 1982. Habitat require-
ments of boreal and hawk owls in interior Alaska.
Pages 188-196 in W.N. Ladd and P.P. Schempf, eds.
Proc. of a symposium and workshop on raptor man-
agement and biology in Alaska and western Canada.
U.S. Fish Wildl. Serv., Alaska Reg. Off., FWS/AK7
PROC-82.
Merritt, J.F. 1981. Clethrionomys gapperi. Mamm. Spe-
cies 146:1-9.
Miller, EL. 1982. Caribou, in J.A. Chapman and G.A.
Feldhamer, eds. Wild mammals of North American:
biology, management, and economics. Johns
Hopkins Univ. Press, Baltimore and London.
Miller, H.G., J.M. Cooper, J.D. Miller, and O.J.L. Pauline.
1979. Nutrient cycles in pine and their adaptation to
poor soils. Can. J. For. Res. 9:19-26.
Mindell, D.P., and R.A. Dotson. 1982. Distribution and
abundance of nesting raptors in southwestern Alaska.
Pages 112-137 in W.N. Ladd and P.P. Schempf, eds.
Proc. of a symposium and workshop on raptor man-
agement and biology in Alaska and western Canada.
U.S. Fish Wildl. Serv., Alaska Reg. Off., FWS/AK7
PROC-82.
Minnesota Department of Natural Resources. 1984. Rec-
ommendations for the protection of ecologically sig-
nificant peatlands in Minnesota. Minn. Dep. Nat.
Resour. 55pp. + maps.
Mitsch, W.J., and J.G. Gosselink. 1986. Wetlands. Van
Nostrand Reinhold, New York. 539pp.
, and . 1993. Wetlands. Second ed. Van
Nostrand Reinhold, New York. 722pp.
Modafferi, M.M. 1972. Aspects of the reproductive biol-
ogy of the red squirrel (Tamiasciurus hud.sonicu.s~) in
interior Alaska. M.S. Thesis, Univ. Alaska,
Fairbanks. 82pp.
Moore, P.O. 1984. The classification of mires: an intro-
duction. Pages 1-10 in P.O. Moore, ed. European
mires. Academic Press Inc. (London) Ltd.
, and D.J. Bellamy. 1974. Peatlands. Springer-
Verlag New York Inc. 221pp.
, D.L. Merryfield, and M.D.R. Price. 1984. The
vegetation and development of blanket mires. Pages
201-235 in P.D. Moore, ed. European mires. Aca-
144
-------
Literature Cited
demic Press Inc. (London) Ltd.
Moore, T.R. 1980. The nutrient status of subarctic wood-
land soils. Arct. and Alpine Res. 12(2): 147-160.
1981. Controls on the decomposition of organic
matter in subarctic spruce-lichen woodland soils. Soil
Sci. 131(2):107-113.
. 1983. Winter-time litter decomposition in a sub-
arctic woodland. Arct. and Alpine Res. 15(3):413-
418.
. 1987. A preliminary study of the effects of drain-
age and harvesting on water quality in ombrotrophic
bogs near Sept-lies, Quebec. Water. Resour. Bull.
23(5):785-791.
. 1988. Dissolved iron and organic matter in north-
ern peatlands. Soil Sci. 145(l):70-76.
. 1989. Plant production, decomposition, and car-
bon efflux in a subarctic patterned fen. Arct. and Al-
pine Res. 21(2):156-162.
, A. Heyes, and N.T. Roulet. 1994. Methane emis-
sions from wetlands, southern Hudson Bay lowland.
J. Geophys. Res. 99(D1): 1455-1467.
, and R. Knowles. 1989. The influence of water
table levels on methane and carbon dioxide emissions
from peatland soils. Can. J. Soil Sci. 69:33-38.
, and . 1990. Methane emissions from fen,
1:7,500,000.
. 1988. Wetlands of Canada. Ecol. Land Classifica-
bog and swamp peatlands in Quebec. Biogeochemis-
try 11:54-61.
Morneau, C., and S. Payette. 1989. Postfire lichen-spruce
woodland recovery at the limit of the boreal forest in
northern Quebec. Can. J. Bot. 67:2770-2782.
Mowrey, R.A., and J.C. Zasada. 1984. Den tree use and
movements of northern flying squirrels in interior
Alaska and implications for forest management.
Pages 351-356 in W.R. Meehan, T.R. Merrell, Jr., and
T.A. Hanley, eds. Fish and wildlife relationships in
old-growth forests. [Proc. symp.] Am. Inst. Fish. Res.
Biol., Morehead City, N.C.
Municipality of Anchorage. 1982. Anchorage wetlands
management plan. Revised. Municipality of Anchor-
age Planning Dep., Anchorage, Alas.
Murie, A. 1963. Birds of Mount McKinley National Park
Alaska. Mount McKinley Nat. Hist. Assoc. 85pp.
Murphy, S.M., B. Kessel, and L.J. Vining. 1984. Water-
fowl populations and limnologic characteristics of
taiga ponds. J. Wildl. Manage. 48(4): 1156-1163.
National Research Council. 1995. Wetlands: characteris-
tics and boundaries. Natl. Acad. Sci., Washington,
D.C.307pp.
National Technical Committee for Hydric Soils. 1991.
Hydric soils of the United States. Third ed. U.S. Soil
Conserv. Serv. Misc. Publ. No. 1491. [unnumbered]
National Wetlands Working Group. 1986. Canada, wet-
land regions in The Natl. Atlas of Canada. Fifth ed.
Energy, Mines and Resour. Canada, Ottawa. Map,
tion Ser., No. 24. Sustainable Dev. Branch, Environ.
Can., Ottawa and Polyscience Publ. Inc., Montreal.
452pp.
Nelson, G.L. 1978. Hydrologic information for land-use
planning Fairbanks vicinity, Alaska. U.S. Geol. Surv.
Open-File Rep. 78-959. 47pp.
Nelson, R.K., K.H. Mautner, and G.R. Bane. 1982. Tracks
in the wildland: a portrayal of Koyukon and
Nunamiut subsistence. Coop. Park Stud. Unit, Univ.
Alaska, Fairbanks. 465pp.
Nero, R.W. 1980. The great gray owl - phantom of the
northern forest. Smithsonian Inst. Press, Washington,
D.C. 167pp.
Newman, D.G., and C.R. Griffin. 1994. Wetland use by
river otters in Massachusetts. J. Wildl. Manage
58(l):18-23.
Nichols, D.S., and J.M. Brown. 1980. Evaporation from
a sphagnum moss surface. J. Hydrol. 48(3-4)289-
302.
Nicholson, J.A. 1988. Alternate strip clearcutting in up-
land black spruce. V. The impact of harvesting on the
quality of water flowing from small basins in shal-
low-soil boreal ecosystems. For. Chron. 64(l):52-58.
Nikonov, V.V., and K.N. Manakov. 1980. Ecological and
biochemical characteristics of the northern taiga for-
ests of the Kola Peninsula. Soviet J. Ecol. 10(5):394-
399.
Nodler, F.A. 1973. Food habits, vocalizations, and terri-
toriality of Alaskan red squirrels (G. Tamiasciurus).
M.S. Thesis, Univ. Alaska, Fairbanks. 86pp.
Noste, N.V., R.J. Barney, and K.P. Burnham. 1979a. Ef-
fects of burning on forest floor characteristics. Pages
10-11 in L.A. Viereck and C.T. Dyrness, eds. Eco-
logical effects of the Wickersham Dome fire near
Fairbanks, Alaska. U.S. For. Serv. Pac. Northwest
For. Range Exp. Stn. Gen. Tech. Rep. PNW-90.
, and C.T. Dyrness. 19796. Mineral soil
characteristics following burning. Pages 12-14 in
L.A. Viereck and C.T. Dyrness, eds. Ecological ef-
fects of the Wickersham Dome fire near Fairbanks,
Alaska. U.S. For. Serv. Pac. Northwest For. Range
Exp. Stn. Gen. Tech. Rep. PNW-90.
Novil/Jki, R.P. 1979. Hydrologic characteristics of
Wisconsin's wetlands and their influence on floods,
stream flow, and sediment. Pages 377-388 in P.E.
Grecson, J.R. Clark, and I.E. Clark, eds. Wetland
functions and values: the state of our understanding.
[Proc. nail. symp. on wetlands, Lake Buena Vista,
Fla., 1978] Am. Water Resour. Assoc., Minneapolis,
Minn.
Nowak, R.M., and J.L. Paradiso. 1983. Walker's mam-
mals of the world. Fourth ed. Johns Hopkins Univ.
145
-------
Functional Profile of Black Spruce Wetlands in Alaska
Press, Baltimore and London. 1362pp. + index.
Odum, E.P. 1979. The value of wetlands: a hierarchical
approach. Pages 16-25 in P.E. Greeson, J.R. Clark,
and I.E. Clark, eds. Wetland functions and values: the
state of our understanding. [Proc. natl. symp. on wet-
lands, Lake Buena Vista, Fla., 1978] Am. Water
Resour. Assoc., Minneapolis, Minn.
Oechel, W.C., and W.T. Lawrence. 1985. Taiga. Pages 66-
94 in B.F. Chabot and H.A. Mooney, eds. Physiologi-
cal ecology of North American plant communities.
Chapman and Hall, New York and London.
, and K. Van Cleve. 1986. Role of bryophytes in nu-
trient cycling. Pages 121-137 in K. Van Cleve, F.S.
Chapin, III, P.W. Flanagan, L.A. Viereck, and C.T.
Dyrness, eds. Forest ecosystems in the Alaskan taiga.
Springer-Verlag, New York.
Osborne, T.O. 1987. Biology of the great gray owl in in-
terior Alaska. Pages 91-95 in R.W. Nero, R.J. Clark,
R.J. Knapton, and R.H. Hamre, eds. Biology and
conservation of northern forest owls: symposium
proceedings, Winnipeg, Manit., 1987. U.S. For. Serv.
Rocky Mt. For. Range Exp. Stn. Gen. Tech. Rep.
RM-142.
Oswood, M.W., K.R. Everett, and D.M. Schell. 1989.
Some physical and chemical characteristics of an arc-
tic beaded stream. Holarct. Ecol. 12:290-295.
Pakarinen, P. 1981. Metal content of ombrotrophic Sph-
agnum mosses in NW Europe. Ann. Bot. Fenn.
18(4):281-292.
Palmer, R.S., editor. 1988a. Handbook of North American
birds. Vol. 4. Yale Univ. Press, New Haven and Lon-
don. 433pp.
, editor. 1988£>. Handbook of North American birds.
Vol. 5. Yale Univ. Press, New Haven and London.
465pp.
Pamplin, W.L., Jr. 1979. Construction-related impacts of
the Trans-Alaska Pipeline System on terrestrial wild-
life habitats. Joint State/Federal Fish Wildl. Advisory
Team Spec. Rep. No. 24. 132pp.
Paradiso, J.L., and R.M. Nowak. 1982. Wolves. Pages
460-474 in J.A. Chapman and G.A. Feldhamer, eds.
Wild mammals of North American: biology, manage-
ment, and economics. Johns Hopkins Univ. Press,
Baltimore and London.
Paragi, T.F., A.J. Magoun, P. Latour, W.N. Johnson, and
M. MacLean. 1994. Marten use of forest openings
created by fire in the taiga. [Poster abstr.] 59th North
Am. Wildl. & Nat. Resour. Conf., Anchorage, Alas.
Parker, G.R. 1984. Use of spruce plantations by snowshoe
hare in New Brunswick. For. Chron. 60(3): 162-166.
. 1986. The importance of cover on use of conifer
plantations by snowshoe hares in northern New
Brunswick. For. Chron. 62(3): 159-163.
Pasitschniak-Arts, M., and S. Lariviere. 1995. Gulo gulo.
Mamm. Species 499:1-10.
Pavlov, A.V, and F.E. Are. 1984. The thermal regime of
thermokarst lakes in central Yakutia. Pages 282-285
in Int. Conference on Permafrost (Fourth), Fairbanks,
Alas., 1983. [Final Proc.] Natl. Acad. Press, Wash-
ington, D.C.
Payette, S. 1988. Late-Holocene development of subarc-
tic ombrotrophic peatlands: allogenic and autogenic
succession. Ecology 69(2):516-531.
, J. Deshaye, and H. Gilbert. 1982. Tree seed popu-
lations at the treeline in Riviere aux Feuilles area,
northern Quebec, Canada. Arct. and Alpine Res.
14(3):215-221.
, L. Gauthier, and I. Grenier. 1986. Dating ice-
wedge growth in subarctic peatlands following defor-
estation. Nature 322:724-727.
Peek, J.M., D.L. Urich, and R.J. Mackie. 1976. Moose
habitat selection and relationships to forest manage-
ment in northeastern Minnesota. Wildl. Monogr.
48:1-65.
Pelton, M.R. 1982. Black bear. Pages 504-514 in J.A.
Chapman and G.A. Feldhamer, eds. Wild mammals
of North American: biology, management, and eco-
nomics. Johns Hopkins Univ. Press, Baltimore and
London.
Perry, H.R., Jr. 1982. Muskrats. Pages 282-325 in J.A.
Chapman and G.A. Feldhamer, eds. Wild mammals
of North American: biology, management, and eco-
nomics. Johns Hopkins Univ. Press, Baltimore and
London.
Petzold, D.E. 1981. The radiation balance of melting
snow in open boreal forest. Arct. and Alpine Res.
13(3):287-293.
Pewe, T.L. 1975. Quaternary geology of Alaska. U.S.
Geol. Surv. Prof. Pap. 835. 145pp. + maps.
. 1982. Geologic hazards of the Fairbanks area,
Alaska. Alaska Div. Geol. Geophys. Surv. Spec. Rep.
15. 109pp.
Ping, C.L. 1987. Soil temperatures profiles of two Alas-
kan soils. Soil Sci. Soc. Am. J. 51(4):1010-1018.
, J.P. Moore, and M.H. Clark. 1992. Wetland prop-
erties of permafrost soils in Alaska. Pages 198-205 in
J.M. Kimble, ed. Characterization, classification, and
utilization of wet soils. [Proc. Eighth Int. Soil Corre-
lation Meeting (VIIIISCOM)] U.S. Soil Conserv.
Serv. Natl. Soil Survey Center, Lincoln, Nebr.
Pomeroy, J.W. 1985. An identification of environmental
disturbances from road developments in subarctic
muskeg. Arctic 38(2):104-111.
Post, R.A. 1976. An ecological study of northern Tug Hill
coyotes. M.S. Thesis, SUNY Coll. Environ. Sci. For.,
Syracuse, N.Y. 93pp.
Prentki, R.T., M.C. Miller, R.J. Barsdate, V. Alexander, J.
Kelley, and P. Coyne. 1980. Chemistry. Pages 76-178
146
-------
Literature Cited
in J.E. Hobbie, ed. Limnology of tundra ponds, Bar-
row, Alaska. Academic Press.
Prevost, Y.H., J.E. Laing, and V.F. Haavisto. 1988. Sea-
sonal damage by insects and squirrels to female re-
productive structures of black spruce, Picea mariana
(Mill.) B.S.P. Can. Entomol. 120:1113-1121.
Pruitt, W.O., Jr. 1978. Boreal ecology. Inst. of Biol., Stud.
in Biol. No. 91. Edward Arnold (Publ.) Ltd., London.
73pp.
. 1984. Snow and living things. Pages 51-77 in R.
Olson, R. Hastings, and F. Geddes, eds. Northern
ecology and resource management. Univ. Alberta
Press, Edmonton.
Putkisto, K. 1980. Site preparation techniques for refores-
tation. Pages 43-48 in M. Murray and R.M. Van
Veldhuizen, eds. Forest regeneration at high latitudes.
[Proc. int. workshop, Fairbanks, Alas., 1979] U.S.
For. Serv. Pac. Northwest For. Range Exp. Stn. Gen.
Tech. Rep. PNW-107.
Pylypec, B., and R.E. Redmann. 1984. Acid-buffering ca-
pacity of foliage from boreal forest species. Can. J.
Bot. 62:2650-2653.
Racine, C.H., and G.M. Ahlstrand. 1991. Thaw response
of tussock-shrub tundra to experimental all-terrain
vehicle disturbances in south-central Alaska. Arctic
44(l):31-37.
, and J.C. Walters. 1991. Groundwater-discharge
wetlands in the Tanana Flats, interior Alaska. U.S.
Army Cold Reg. Res. Eng. Lab. Rep. 91-14. 10pp.
Raine, R.M. 1987. Winter food habits and foraging behav-
ior of fishers (Martes pennanti) and martens (Maries
americana) in southeastern Manitoba. Can. J. Zool.
65:745-747. [Abstr. in Magoun and Johnson 1991]
Rawlinson, S.E. 1986. Peat-resource and surficial-geo-
logic map of the South Kenai Peninsula, Alaska.
Alaska Div. Geol. Geophys. Surv. Rep. Invest. 86-15.
1 sheet.
, and S.B. Hardy. 1982. Peat resource map of
Alaska. Alaska Div. Geol. Geophys. Surv. Alaska
Open File Rep. AOF-152. 1 plate + suppl. + adden-
dum.
Reader, R.J. 1980. Effects of nitrogen fertilizer, shade, and
the removal of new growth on longevity of overwin-
tering bog ericad leaves. Can. J. Bot. 58:1737-1743.
Reed, P.B., Jr. 1988. National list of plant species that
occur in wetlands: Alaska (Region A). U.S. Fish
Wildl. Serv. Biol. Rep. 88(26.11). 86pp.
Remrb'd, J. 1980. Experiences and practices related to
forest regeneration in northern Sweden. Pages 35-41
in M. Murray and R.M. Van Veldhuizen, eds. Forest
regeneration at high latitudes. [Proc. int. workshop,
Fairbanks, Alas., 1979] U.S. For. Serv. Pac. North-
west For. Range Exp. Stn. Gen. Tech. Rep. PNW-
107.
Richardson, C.J. 1979. Primary productivity values in
fresh water wetlands. Pages 131-145 in P.E. Greeson,
J.R. Clark, and J.E. Clark, eds. Wetland functions and
values: the state of our understanding. [Proc. natl.
symp. on wetlands, Lake Buena Vista, Fla., 1978]
Am. Water Resour. Assoc., Minneapolis, Minn.
Reich, L.M. 1981. Microtus pennsylvanicus. Mamm. Spe-
cies 159:1-8.
Rieger, S., J.A. Dement, and D. Sanders. 1963. Soil sur-
vey of Fairbanks area, Alaska. U.S. Soil Conserv.
Serv. Ser. 1959, No. 25. 41pp. + 24 maps.
Riseborough, D.W., and C.R. Burn. 1988. Influence of an
organic mat on the active layer. Pages 633-638 in K.
Senneset, ed. Int. Conference on Permafrost (Fifth),
Trondheim, Norway, 1988. [Proc. Vol. 1] Tapir Publ.,
Trondheim.
Ritchie, J.C., L.C. Cwynar, and R.W. Spear. 1983. Evi-
dence from north-west Canada for an early Holocene
Milankovitch thermal maximum. Nature 305:126-
128.
Roberts, J.L., and N. Bowman. 1986. Diet and ecology of
short-eared owls Asia flammeus breeding on heather
moor. Bird Stud. 33:12-17.
Rothwell, R.L., and V.J. Lieffers. 1987. Preliminary as-
sessment of air temperatures near the ground on a
drained and undrained peatland in central Alberta.
Pages 195-201 in C.D.A. Rubec and R.P. Overend,
compilers. Proc. Symposium '87 Wetlands/Peatlands,
Edmonton, Alta., 1987.
Roulet, N.T. 1991. Stormflow production in a headwater
basin swamp. Nordic Hydrol. 22:161-174.
. 1987. The influence of wetlands on the hydrology
of permafrost drainage basins. Pages 333-339 in
C.D.A. Rubec and R.P. Overend, compilers. Proc.
Symposium '87 Wetlands/Peatlands, Edmonton,
Alta., 1987.
, A. Jano, C.A. Kelly, L.F. Klinger, T.R. Moore, R.
Protz, J.A. Ritter, and W.R. Rouse. 1994. Role of the
Hudson Bay lowland as a source of atmospheric
methane. J. Geophys. Res. 99(D1): 1439-1454.
Rowe, C.L., W.J. Sadinski, and W.A. Dunson. 1992. Ef-
fects of acute and chronic acidification on three lar-
val amphibians that breed in temporary ponds. Arch.
Environ. Contain. Toxicol. 23:339-350.
Rowe, J.S. 1984. Lichen woodland in northern Canada.
Pages 225-237 in R. Olson, R. Hastings, and F.
Geddes, eds. Northern ecology and resource manage-
ment. Univ. Alberta Press, Edmonton.
Rundquist, L.A, N.E. Bradley, J.E. Baldrige, P.D. Hamp-
ton, T.R. Jennings, and M.R. Joyce. 1986. Best man-
agement practices for placer mining. Technical
report. Prepared by Entrix, Inc. for Alaska Dep. Fish
and Game, Habitat Div., Juneau, Alas. 250pp.
Russell, D.E., and A.M. Martell. 1984. Winter range ecol-
747
-------
Functional Profile of Black Spruce Wetlands in Alaska
ogy of caribou (Rangifertarandus). Pages 117-144 in
R. Olson, R. Hastings, and F. Geddes, eds. Northern
ecology and resource management. Univ. Alberta
Press, Edmonton.
Ruuhijarvi, R. 1983. The Finnish mire types and their re-
gional distribution. Pages 47-67 in A.J.P. Gore, ed.
4B. Mires: swamp, bog, fen and moor - regional stud-
ies. Elsevier Sci. Publ. Co., Amsterdam.
Salonius, P.O. 1983. Effects of organic-mineral soil mix-
tures and increasing temperature on the respiration of
coniferous raw humus material. Can. J. For. Res.
13:102-107.
Samuel, D.E., and B.B. Nelson. 1982. Foxes. Pages 475-
490 in J.A. Chapman and G.A. Feldhamer, eds. Wild
mammals of North American: biology, management,
and economics. Johns Hopkins Univ. Press, Balti-
more and London.
Santelmann, M.V., and E. Gorham. 1988. The influence of
airborne road dust on the chemistry of Sphagnum
mosses. J.Ecol. 76:1219-1231.
Sanville, W. 1988. Response of an Alaskan wetland to nu-
trient enrichment. Aquatic Bot. 30:231-243.
Saperstein, L.B. 1993. Winter forage selection by barren-
ground caribou: effects of fire and snow. M.S. The-
sis, Univ. Alaska, Fairbanks. 79pp.
Sather, J.H., and R.D. Smith. 1984. An overview of ma-
jor wetland functions. U.S. Fish Wildl. Serv. FWS/
OBS-84/18. 68pp.
Savikko, H., and T. Page. 1990. 1989 preliminary Alaska
commercial fisheries harvests and values. Alaska
Dep. Fish Game Div. Commer. Fish. Reg. Inf. Rep.
No. 5J90-07. 102pp.
Schaefer, J.A., and W.O. Pruitt, Jr. 1991. Fire and wood-
land caribou in southeastern Manitoba. Wildl.
Monogr. 116:1-39.
Schell, D.M. 1983. Carbon-13 and carbon-14 abundances
in Alaskan aquatic organism: delayed production
from peat in arctic food webs. Science 219:1068-
1071.
, and P.J. Ziemann. 1983. Accumulation of peat
carbon in the Alaska Arctic Coastal Plain and its role
in biological productivity. Pages 1105-1110 in Int.
Conference on Permafrost (Fourth), Fairbanks, Alas.,
1983. [Proc.] Natl. Acad. Press, Washington, D.C.
Schlentner, R.E., and K. Van Cleve. 1985. Relationships
between CO2 evolution from soil, substrate tempera-
ture, and substrate moisture in four mature forest
types in interior Alaska. Can. J. For. Res. 15:97-106.
Schwartz, C.C., and A.W. Franzmann. 1991. Interrelation-
ship of black bears to moose and forest succession in
the northern coniferous forest. Wildl. Monogr. 113:1-
58.
Scotter, G.W. 1967. The winter diet of barren-ground cari-
bou in northern Canada. Can. Field-Nat. 81:33-39.
Scale, D.B. 1982. Physical factors influencing oviposition
by the woodfrog, Rana sylvatica, in Pennsylvania.
Copeia 1982:(3):627-635.
Senyk, J.P., and E.T. Oswald. 1983. Ecological relation-
ships within the discontinuous permafrost zone of
southern Yukon Territory. Pages 1121-1126 in Int.
Conference on Permafrost (Fourth), Fairbanks, Alas.,
1983. [Proc.] Natl. Acad. Press, Washington, D.C.
Seppala, M. 1982. An experimental study of the formation
of palsas. Pages 36-42 in H.M. French, ed. Can. Per-
mafrost Conf. (Fourth), Calgary, Alia., 1981. [Proc.]
Natl. Res. Counc. Can., Ottawa.
Servos, M.C. 1987. Summer habitat use by great gray
owls in southeastern Manitoba. Pages 108-114 in
R.W. Nero, R.J. Clark, R.J. Knapton, and R.H.
Hamre, eds. Biology and conservation of northern
forest owls: symposium proceedings, Winnipeg,
Manit., 1987. U.S. For. Serv. Rocky Mt. For. Range
Exp. Stn. Gen. Tech. Rep. RM-142.
Sharratt, B.S. 1992. Growing season trends in the Alaskan
climate record. Arctic 45(2): 124-127.
Sheffield, S.R., and C. M. King. 1994. Mustela nivalis.
Mamm. Species 454:1-10.
Siegel, D.I. 1983. Ground water and the evolution of pat-
terned mires, Glacial Lake Agassiz Peatlands, north-
ern Minnesota. J. Ecol. 71(3):913-921.
, and P.H. Glaser. 1987. Groundwater flow in a bog-
fen complex, Lost River peatland, northern Minne-
sota. J. Ecol. 75:743-754.
, A.S. Reeve, P.H. Glaser, and E.A. Romanowicz.
1995. Climate-driven flushing of pore water in
peatlands. Nature 374:531-533.
Sikora, L.J., and D.R. Keeney. 1983. Further aspects of
soil chemistry under anaerobic conditions. Pages
247-256 in A.J.P. Gore, ed. 4A. Mires: swamp, bog,
fen, and moor - general studies. Elsevier Sci. Publ.
Co., Amsterdam.
Silversides, C.R. 1983. Energy from forest biomass for re-
mote communities. Pages 418-426 in R.W. Wein,
R.R. Riewe, and I.R. Methven, eds. Resources and
dynamics of the Boreal Zone. [Proc. conf., Thunder
Bay, Ontario, 1982] Assoc. Can. Univ. North. Stud.
Sims, R.A., and J.M. Stewart. 1981. Aerial biomass dis-
tribution in an undisturbed and disturbed subarctic
bog. Can. J. Bot. 59:782-786.
Sirois, L., and S. Payette. 1991. Reduced postfire tree re-
generation along a boreal forest-forest-tundra transect
in northern Quebec. Ecology 72(2):619-627.
Sjors, H. 1950. On the relation between vegetation and
electrolytes in north Swedish mire waters. Oikos
2(2):241-258.
. 1963. Bogs and fens in the Hudson Bay lowlands.
Arctic 12:3-19.
. 1983. Mires of Sweden. Pages 69-94 in A.J.P.
148
-------
Literature Cited
Gore, ed. 4B. Mires: swamp, bog, fen and moor -
regional studies. Elsevier Sci. Publ. Co., Amsterdam.
Skeel, M.A. 1983. Nesting success, density, philopatry,
and nest-site selection of the whimbrel (Numenius
phaeopus) in different habitats. Can. J. Zool.
61(l):218-225.
Skoog, R.O. 1968. Ecology of the caribou (Rangifer
tarandus grantf) in Alaska. Ph.D. Thesis, Univ. Cali-
fornia, Berkeley. 699pp.
Skousen, J., and J. Sencindiver. 1988. The latest word on
wetlands. Green Lands 18(2):25-27.
Skre, O., and W.C. Oechel. 1979. Moss production in a
black spruce Picea mariana forest with permafrost
near Fairbanks, Alaska, as compared with two per-
mafrost-free stands. Holarct. Ecol. 2:249-254.
, and . 1981. Moss functioning in different
taiga ecosystems in interior Alaska. I. Seasonal, phe-
notypic, and drought effects on photosynthesis and
response patterns. Oecologia 48:50-59.
, , and P.M. Miller. 1983a. Patterns of trans-
location of carbon in four common moss species in a
black spruce (Picea mariana) dominated forest in
interior Alaska. Can. J. For. Res. 13:869-878.
, , and P.M. Miller. 1983/7. Moss leaf water
content and solar radiation at the moss surface in a
mature black spruce forest in central Alaska. Can. J.
For. Res. 13:860-868.
Slack, N.G., D.H. Vitt, and D.G. Horton. 1980. Vegetation
gradients of minerotrophically rich fens in western
Alberta. Can. J. Bot. 58:330-350.
Slaughter, C.W. 1983. Summer short-wave radiation at a
subarctic forest site. Can. J. For. Res. 13:740-746.
, and J.W. Aldrich, compilers. 1989. Annotated bib-
liography on soil erosion and erosion control in sub-
arctic and high-latitude regions of North America.
U.S. For. Serv. Pac. Northwest Res. Stn. Gen. Tech.
Rep. PNW-GTR-253. 234pp.
, and C.S. Benson. 1986. Seasonal snow and aufeis
in Alaska's taiga. Pages 101-109 in D.L. Kane, ed.
Proc. of the Symposium: Cold Regions Hydrology,
University of Alaska-Fairbanks. Am. Water Resour.
Assoc., Bethesda, Md.
, and D.L. Kane. 1979. Hydrologic role of shallow
organic soils in cold climates. Pages 380-389 in Ca-
nadian Hydrology Symposium: 79. [Proc.] Natl. Res.
Counc. Can., Ottawa.
, and L.A. Viereck. 1986. Climatic characteristics of
the taiga in interior Alaska. Pages 9-21 in K. Van
Cleve, F.S. Chapin, III, P.W. Flanagan, L.A. Viereck,
and C.T. Dyrness, eds. Forest ecosystems in the Alas-
kan taiga. Springer-Verlag, New York.
Smolen, M.J., and B.L. Keller. 1987. Microtus
longicaudus. Mamm. Species 271:1-7.
Snyder, J.E., and J.A. Bissonette. 1987. Marten use of
clear-cuttings and residual forest stands in western
Newfoundland. Can. J. Zool. 65:169-174.
Soil Survey Staff. 1994. Keys to soil taxonomy. Sixth ed.
U.S. Gov. Printing Off. 300-124/00122. 306pp.
Sparrow, S.D., C.V. Davenport, and R.C. Gordon. 1978.
Response of microorganisms to hot crude oil spills on
a subarctic taiga soil. Arctic 31(3):324-338.
, and E.B. Sparrow. 1988. Microbial biomass and
activity in a subarctic soil ten years after crude oil
spills. J. Environ. Qual. 17(2):304-309.
Speight, M.C.D., and R.E. Blackith. 1983. The animals.
Pages 349-365 in A.J.P. Gore, ed. 4A. Mires: swamp,
bog, fen, and moor - general studies. Elsevier Sci.
Publ. Co., Amsterdam.
Spindler, M.A. 1976. Ecological survey of the birds,
mammals and vegetation of Fairbanks Wildlife Man-
agement Area. M.S. Thesis, Univ. Alaska, Fairbanks.
258pp.
, and B. Kessel. 1980. Avian populations and habi-
tat use in interior Alaska taiga. Syesis 13:61-104.
Spreyer, M.F. 1987. A floristic analysis of great gray owl
habitat in Aitkin County, Minnesota. Pages 96-100 in
R.W. Nero, R.J. Clark, R.J. Knapton, and R.H.
Hamre, eds. Biology and conservation of northern
forest owls: symposium proceedings, Winnipeg,
Manit., 1987. U.S. For. Serv. Rocky Mt. For. Range
Exp. Stn. Gen. Tech. Rep. RM-142.
Stark, J.R., and R.G. Brown. 1988. Hydrology and water
quality of a wetland used to receive wastewater efflu-
ent, St. Joseph, Minnesota. Pages 197-204 in J.A.
Kusler and G. Brooks, eds. Proc. of the National
Wetland Symposium: Wetland Hydrology, Chicago,
111., 1987. Assoc. State Wetland Managers Tech. Rep.
6, Berne, N.Y.
Stephenson, R.O. 1984. The relationship of fire history to
furbearer populations and harvest. Alaska Dep. Fish
Game Final Rep, Fed. Aid Wildl. Restor. Proj. W-22-
2, Job 7.13R. 86pp.
Steventon, J.D., and J.T. Major. 1982. Marten use of habi-
tat in a commercially clear-cut forest. J. Wildl. Man-
age. 46(1):175-182.
Storey, K.B., and J.M. Storey. 1984. Biochemical
adaption for freezing tolerance in the wood frog,
Rana sylvatica. J. Comp. Physiol. B 155:29-36.
Strahler, A.N. 1963. The earth sciences. Harper & Row,
Publ., New York. 681pp.
Strang, R.M., and A.H. Johnson. 1981. Fire and climax
spruce forests in central Yukon. Arctic 34(1):60-61.
Strickland, M.A., C.W. Douglas, M. Novak, and N.P.
Hunziger. 1982. Marten. Pages 599-612 in J.A.
Chapman and G.A. Feldhamer, eds. Wild mammals
of North American: biology, management, and eco-
nomics. Johns Hopkins Univ. Press, Baltimore and
London.
149
-------
Functional Profile of Black Spruce Wetlands in Alaska
Stuen, O.H., and T.K. Spids0. 1988. Invertebrate abun-
dance in different forest habitats as animal food avail-
able to capercaillie Tetrao urogallus chicks. Scand. J.
For. Res. 3(4):527-532.
Summerbell, R.C. 1989. Microfungi associated with the
mycorrhizal mantle and adjacent microhabitats
within the rhizosphere of black spruce. Can. J. Bot.
67:1085-1095.
Svendsen, G.E. 1982. Weasels. Pages 613-628 in J.A.
Chapman and G.A. Feldhamer, eds. Wild mammals
of North American: biology, management, and eco-
nomics. Johns Hopkins Univ. Press, Baltimore and
London.
Svensson, B.H., and T. Rosswall. 1984. In situ methane
production from acid peat in plant communities with
different moisture regimes in a subarctic mire. Oikos
43:341-350.
Swanson, O.K., and D.F. Grigal. 1989. Vegetation indica-
tors of organic soil properties in Minnesota. Soil Sci.
Soc. Am. J. 53(2):491-495.
, and . 1991. Biomass, structure, and trophic
environment of peatland vegetation in Minnesota.
Wetlands 11(2):279-302.
Swanson, L.E., and R.L. Rothwell. 1986. Thawing of
ground frost on a drained and undrained boreal wet-
land site. Pages 231-236 in D.L. Kane, ed. Proc. of
the Symposium: Cold Regions Hydrology, Univer-
sity of Alaska-Fairbanks. Am. Water Resour. Assoc.,
Bethesda, Md.
Swanson, S.A. 1996. Small mammal populations in post-
fire black spruce (Picea mariana) serai communities
in the upper Kobuk River valley, Alaska. Unpubl.
Draft Final Rep. U.S. Natl. Park Serv. Tech. Bull, [in
prep.].
Talbot, S.S., M.D. Fleming, and CJ. Markon. 1986. Inter-
mediate-scale vegetation mapping of Kanuti National
Wildlife Refuge, Alaska using Landsat MSS digital
data. Pages 392-406 in 1986 ASPRS-ACSM Fall
Convention, Anchorage, Alas. Am. Soc. Photogram-
metry Remote Sensing ASPRS Tech. Pap., Falls
Church, Va.
Tallis, J.H. 1983. Changes in wetland communities. Pages
311-347 in A.J.P. Gore, ed. 4A. Mires: swamp, bog,
fen, and moor - general studies. Elsevier Sci. Publ.
Co., Amsterdam.
Taylor, J.A. 1983. The peatlands of Great Britain and Ire-
land. Pages 1-46 in A.J.P. Gore, ed. 4B. Mires:
swamp, bog, fen and moor regional studies.
Elsevier Sci. Publ. Co., Amsterdam.
Telfer, E.S. 1984. Circumpolar distribution and habitat re-
quirements of moose (Alces alces). Pages 145-182 in
R. Olson, R. Hastings, and F. Geddes, eds. Northern
ecology and resource management. Univ. Alberta
Press, Edmonton.
Thie, J. 1974. Distribution and thawing of permafrost in
the southern part of the discontinuous permafrost
zone in Manitoba. Arctic 27:189-200.
Thorson, R.M., and R.D. Guthrie. 1992. Stratigraphy of
the Colorado Creek mammoth locality, Alaska. Qua-
ternary Res. 37:214-228.
Tilton, D.L. 1977. Seasonal growth and foliar nutrients of
Larix laricina in three wetland ecosystems. Can. J.
Bot. 55:1291-1298.
. 1978. Comparative growth and foliar element con-
centrations of Larix laricina over a range of wetland
types in Minnesota. J. Ecol. 66:499-512.
Timoney, K.P., G.H. La Roi, S.C. Zoltai, and A.L.
Robinson. 1992. The high subarctic forest-tundra of
northwestern Canada: position, width, and vegetation
gradients in relation to climate. Arctic 45(l):l-9.
, and R.W. Wein. 1991. The areal pattern of burned
tree vegetation in the Subarctic Region of northwest-
ern Canada. Arctic 44(3):223-230.
Tiner, R.W. 1984. Wetlands of the United States: current
status and recent trends. U.S. Fish Wildl. Serv., Habi-
tat Resour., Newton Corner, Mass. 59pp.
1989. An update of federal wetland delineation
techniques. Pages 13-23 in D.W. Fisk, ed. Wetlands:
concerns and successes. [Proc. symp., Tampa, Fla.,
1989] Am. Water Resour. Assoc., Bethesda, Md.
Toweill, D.E., and J.E. Tabor. 1982. River otter. Pages
688-703 in J.A. Chapman and G.A. Feldhamer, eds.
Wild mammals of North American: biology, manage-
ment, and economics. Johns Hopkins Univ. Press,
Baltimore and London.
Trapp, G.R. 1962. Snowshoe hares in Alaska. II. Home
range and ecology during an early population in-
crease. M.S. Thesis, Univ. Alaska, Fairbanks. 137pp.
Troth, J.L., F.J. Deneke, and L.M. Brown. 1976. Upland
aspen/birch and black spruce stands and their litter
and soil properties in interior Alaska. For. Sci. 22:33-
44.
Tryon, PR., and F.S. Chapin III. 1983. Temperature con-
trol over root growth and root biomass in taiga forest
trees. Can. J. For. Res. 13(5):827-833.
Tumlison, R. 1987. Felis lynx. Mamm. Species 269:1-8.
Tyrrell, L.E., and R.E.J. Boerner. 1987. Larix laricina and
Picea mariana: relationships among leaf life-span,
foliar nutrient patterns, nutrient conservation, and
growth efficiency. Can. J. Bot. 65:1570-1577.
Underwood, L., and J.A. Mosher. 1982. Arctic fox. Pages
491-503 in J.A. Chapman and G.A. Feldhamer, eds.
Wild mammals of North American: biology, manage-
ment, and economics. Johns Hopkins Univ. Press,
Baltimore and London.
U.S. Fish and Wildlife Service. 1987. Kanuti National
Wildlife Refuge final comprehensive plan, wilder-
ness review and environmental impact statement
750
-------
Literature Cited
U.S. Fish Wildl. Serv., Anchorage, Alas. 326pp.
U.S. Geological Survey. 1978. Water resources data for
Alaska, Water Year 1977. U.S. Geol. Surv. Water-
Data Rep. AK-77-1. 439pp.
Urban, N.R., and S.J. Eisenreich. 1988. Nitrogen cycling
in a forested Minnesota bog. Can. J. Bot. 66(3):434-
449.
Valkenburg, P. 1976. A study of the brown bear (Ursus
arctos) in the proposed northeastern addition to
Mount McKinley National Park. M.S. Thesis, Univ.
Alaska, Fairbanks. 88pp.
Van Cleve, K., R. Barney, and R. Schlentner. 1981. Evi-
dence of temperature control of production and nutri-
ent cycling in two interior Alaska black spruce
ecosystems. Can. J. For. Res. 11:258-273.
F.S. Chapin III, C.T. Dyrness, and L.A. Viereck.
1991. Element cycling in taiga forests: state-factor
control. BioScience 41(2):78-88.
, , P.W. Flanagan, L.A. Viereck, and C.T.
Dyrness, editors. 1986. Forest ecosystems in the
Alaskan taiga. Springer-Verlag, New York. 230pp.
, and C.T. Dyrness. 1983a. Conclusions and direc-
tions for future research in taiga forest ecosystems.
Can. J. For. Res. 13:914-916.
, and . 1983i>. Effects of forest-floor distur-
bance on soil-solution nutrient composition in a black
spruce ecosystem. Can. J. For. Res. 13:894-902.
, , and L.A. Viereck. 1980. Nutrient cycling
in interior Alaska flood plains and its relationship to
regeneration and subsequent forest development.
Pages 11 -18 in M. Murray and R.M. Van Veldhuizen,
eds. Forest regeneration at high latitudes. [Proc. int.
workshop, Fairbanks, Alas., 1979] U.S. For. Serv.
Pac. Northwest For. Range Exp. Stn. Gen. Tech. Rep.
PNW-107.
, , , J. Fox, F.S. Chapin, III, and W.
Oechel. 1983. Taiga ecosystems in interior Alaska.
BioScience 33(l):39-44.
, L. Oliver, R. Schlentner, L.A. Viereck, and C.T.
Dyrness. 1983. Productivity and nutrient cycling in
taiga forest ecosystems. Can. J. For. Res. 13:747-766.
, and L.A. Viereck. 1983. A comparison of succes-
sional sequences following fire on permafrost-domi-
nated and permafrost-free sites in interior Alaska.
Pages 1286-1291 in Int. Conference on Permafrost
(Fourth), Fairbanks, Alas., 1983. [Proc.] Natl. Acad.
Press, Washington, D.C.
, , and C.T. Dyrness. 1983. Dynamics of a
black spruce ecosystem in comparison to other forest
types: a multi-disciplinary study in interior Alaska.
Pages 148-166 in R.W. Wein, R.R. Riewc, and I.R.
Methven, eds. Resources and dynamics of the Boreal
Zone. [Proc. conf., Thunder Bay, Ontario, 1982]
Assoc. Can. Univ. North. Stud.
, and J. Yarie. 1986. Interaction of temperature,
moisture, and soil chemistry in controlling nutrient
cycling and ecosystem development in the taiga of
Alaska. Pages 160-189 in K. Van Cleve, F.S. Chapin,
III, P.W. Flanagan, L.A. Viereck, and C.T. Dyrness,
eds. Forest ecosystems in the Alaskan taiga.
Springer-Verlag, New York.
van derValk, A.G., C.B. Davis, J.L. Baker, andC.E. Beer.
1979. Natural fresh water wetlands as nitrogen and
phosphorus traps for land runoff. Pages 457-467 in
P.E. Greeson, J.R. Clark, and J.E. Clark, eds. Wetland
functions and values: the state of our understanding.
[Proc. natl. symp. on wetlands, Lake Buena Vista,
Fla., 1978] Am. Water Resour. Assoc., Minneapolis,
Minn.
van Everdingen, R.O. 1988. Perennial discharge of
subpermafrost groundwater in two small drainage ba-
sins, Yukon, Canada. Pages 639-643 in K. Senneset,
ed. Int. Conference on Permafrost (Fifth),
Trondheim, Norway, 1988. [Proc. Vol. 1] Tapir Publ,
Trondheim.
van Hees, W.W.S. 1990. Boreal forested wetlands - what
and where in Alaska. For. Ecol. Manage. 33/34:425-
438.
Vasander, H. 1984. Effect of forest amelioration on diver-
sity in an ombrotrophic bog. Ann. Bot. Fenn. 21:7-
15.
Vedagiri, U., and J. Ehrenfeld. 1991. Effects of Sphagnum
moss and urban runoff on bioavailabiltiy of lead and
zinc from acidic wetlands of the New Jersey
pinelands. Environ. Pollut. 72:317-330.
Verry, E.S., and D.H. Boelter. 1979. Peatland hydrology.
Pages 389-402 in P.E. Greeson, J.R. Clark, and J.E.
Clark, eds. Wetland functions and values: the state of
our understanding. [Proc. natl. symp. on wetlands,
Lake Buena Vista, Fla., 1978] Am. Water Resour.
Assoc., Minneapolis, Minn.
, and D.R. Timmons. 1982. Waterborne nutrient
flow through an upland-peatland watershed in Min-
nesota. Ecology 63(5):1456-1467.
Viereck, L.A. 1970. Forest succession and soil develop-
ment adjacent to the Chena River in interior Alaska.
Arct. and Alpine Res. 2( 1): 1 -26.
. 1973a. Wildfire in the taiga of Alaska. Quaternary
Res. 3:465-495.
. 1973i>. Ecological effects of river flooding and
forest fires on permafrost in the taiga of Alaska.
Pages 60-67 in Int. Conference on Permafrost (Sec-
ond), Yakutsk, U.S.S.R., 1973. [North Am. Contrib.]
Natl. Acad. Sci., Washington, D.C.
. 1975. Forest ecology of the Alaska taiga. Pages I-
1 to 1-22 in Proc. Circumpolar Conference on North-
ern Ecology, Ottawa, 1975.
. 1979. Characteristics of treeline plant communi-
757
-------
Functional Profile of Black Spruce Wetlands in Alaska
ties in Alaska. Holarct. Ecol. 2:228-238.
. 1982. Effects of fire and firelines on active layer
thickness and soil temperatures in interior Alaska.
Pages 123-135 in H.M. French, ed. Can. Permafrost
Conf. (Fourth), Calgary, Alta., 1981. [Proc.] Natl.
Res. Counc. Can., Ottawa.
. 1983. The effects of fire in black spruce ecosys-
tems of Alaska and northern Canada. Pages 201-220
in R.W. Wein and D.A. MacLean, eds. The role of
fire in northern circumpolar ecosystems. John Wiley
& Sons Ltd.
, and C.T. Dyrness, tech. eds. 1979. Ecological ef-
fects of the Wickersham Dome fire near Fairbanks,
Alaska. U.S. For. Serv. Pac. Northwest For. Range
Exp. Stn. Gen. Tech. Rep. PNW-90. 71pp.
, and 1980. A preliminary classification sys-
tem for vegetation of Alaska. U.S. For. Serv. Pac.
Northwest For. Range Exp. Stn. Gen. Tech. Rep.
PNW-106. 38pp.
, , A.R. Batten, and KJ. Wenzlick. 1992. The
Alaska vegetation classification. U.S. For. Serv. Pac.
Northwest Res. Stn. Gen. Tech. Rep. PNW-GTR-
286. 278pp.
_, , K. Van Cleve, and M.J. Foote. 1983. Veg-
etation, soils, and forest productivity in selected for-
est types in interior Alaska. Can. J. For. Res.
13:703-720.
, and M.J. Foote. 1979a. Vegetation analysis. Pages
25-34 in L.A. Viereck and C.T. Dyrness, tech. eds.
Ecological effects of the Wickersham Dome fire near
Fairbanks, Alaska. U.S. For. Serv. Pac. Northwest
For. Range Exp. Stn. Gen. Tech. Rep. PNW-90.
, and . 19796. Permafrost. Pages 17-21 in
L.A. Viereck and C.T. Dyrness, tech. eds. Ecological
effects of the Wickersham Dome fire near Fairbanks,
Alaska. U.S. For. Serv. Pac. Northwest For. Range
Exp. Stn. Gen. Tech. Rep. PNW-90.
, , C.T. Dyrness, K. Van Cleve, D. Kane, and
R. Seifert. 1979. Preliminary results of experimental
fires in the black spruce type of interior Alaska. U.S.
For. Serv. Pac. Northwest For. Range Exp. Stn. Res.
Note PNW-332. 27pp.
, and E.L Little, Jr. 1972. Alaska trees and shrubs.
U.S. For. Serv. Agric. Handb. No. 410. 265pp.
, and L.A. Schandelmeier. 1980. Effects of fire in
Alaska and adjacent Canada a literature review.
U.S. Bur. Land Manage. Alaska Tech. Rep. 6 (ELM/
AK/TR-80/06). 124pp.
, and K. Van Cleve. 1984. Some aspects of vegeta-
tion and temperature relationships in the Alaska taiga.
Pages 129-142 in J.H. McBeath, ed. The potential
effects of carbon dioxide-induced climatic changes in
Alaska. [Proc. conf.] Univ. Alaska-Fairbanks School
of Agric. and Land Resour. Manag. Misc. Pub. 83-1.
, , and C.T. Dyrness. 1986. Forest ecosystem
distribution in the taiga environment. Pages 22-43 in
K. Van Cleve, F.S. Chapin, III, P.W. Flanagan, L.A.
Viereck, and C.T. Dyrness, eds. Forest ecosystems in
the Alaskan taiga. Springer-Verlag, New York.
Village, A. 1987. Numbers, territory-size and turnover of
short-eared owls Asia flammeus in relation to vole
abundance. Ornis Scand. 18:198-204.
Vitousek, P.M., PA. Matson, and K. Van Cleve. 1989. Ni-
trogen availability and nitrification during succes-
sion: primary, secondary, and old-field seres. Plant
and Soil 115:229-239.
Vitt, D.H., J.E. Marsh, and R.B. Bovey. 1988. A photo-
graphic field guide to the mosses, lichens and ferns of
northwest North America. Lone Pine Publishing,
Edmonton, Alta. 296pp.
, and N.G. Slack. 1975. An analysis of the vegeta-
tion of Sphagnum-dominated kettle-hole bogs in re-
lation to environmental gradients. Can. J. Bot.
53:332-359.
Wahrhaftig, C. 1965. Physiographic divisions of Alaska.
U.S. Geol. Surv. Prof. Pap. 482. 52pp.
Waldman, B. 1982. Adaptive significance of communal
oviposition in wood frogs (Rana sylvatica). Behav.
Ecol. Sociobiol. 10:169-174.
Walker, D.A., P.J. Webber, E.F. Binnian, K.R. Everett,
N.D. Lederer, E.A. Nordstrand, and M.D. Walker.
1987. Cumulative impacts of oil fields on northern
Alaskan landscapes. Science 238:757-761.
Walker, L.R. 1989. Soil nitrogen changes during primary
succession on a floodplain in Alaska, U.S.A. Arct.
and Alpine Res. 21(4):341-349.
, J.C. Zasada, and F.S. Chapin, III. 1986. The role
of life history processes in primary succession on an
Alaskan floodplain. Ecology 67(5): 1243-1253.
Wallace, R.E. 1948. Cave-in lakes in the Nabesna,
Chisana, and Tanana River valleys, eastern Alaska. J.
Geol. 56:171-181.
Walley, W.J. 1989. Breeding blackpoll warblers,
Dendroica striata, in Duck Mountain Provincial
Park, Manitoba. Can. Field-Nat. 103(3):396-397.
Wang, E.I.C., T. Mueller, and M.M. Micko. 1985. Drain-
age effect on growth and wood quality of some bog
grown trees in Alberta. For. Chron. 61(6):489-493.
Wang, X.-C, and M.-A. Geurts. 1991. Post-glacial veg-
etation history of the Ittlemit Lake basin, southwest
Yukon Territory. Arctic 44(1):23-30.
Warner, B.C., and H.J. Kubiw. 1987. Origin of sphagnum
kettle bogs, southwestern Ontario. Pages 543-550 in
C.D.A. Rubec and R.P. Overend, compilers. Proc.
Symposium '87 Wetlands/Peatlands, Edmonton,
Alta., 1987.
Washburn, A.L. 1973. Thermokarst. Pages 232-239 in
A.L. Washburn. Periglacial processes and environ-
752
-------
Literature Cited
ments. St. Martin's Press, New York.
Watson, D. 1977. The hen harrier. T. & A.D. Poyser Ltd.,
Berkhamsted, U.K. 307pp.
Waughman, G.J., and D.J. Bellamy. 1980. Nitrogen fixa-
tion and the nitrogen balance in peatland ecosystems.
Ecology 61(5):1185-1198.
Weber, M.G. 1982. Nitrogen dynamics through the forest
floor of two interior Alaska black spruce ecosystems.
Ph.D. Thesis. Univ. Alaska, Fairbanks. 139pp.
, and K. Van Cleve. 1981. Nitrogen dynamics in the
forest floor of interior Alaska black spruce ecosys-
tems. Can. J. For. Res. 11:743-751.
, and . 1984. Nitrogen transformations in
feather moss and forest floor layers of interior Alaska
black spruce ecosystems. Can. J. For. Res. 14:278-
290.
Weedon, R.B., and L.N. Ellison. 1968. Upland game birds
of forest and tundra. Alaska Dep. Fish Game Wildl.
Booklet Ser. No. 3. 44pp.
Wegener, J.W.M., M.J.M. van Schaik, and H. Aiking.
1992. Active biomonitoring of polycyclic aromatic
hydrocarbons by means of mosses. Environ. Pollut.
76:15-18.
Wein, R.W., and J.M. Moore. 1977. Fire history and rota-
tions in the New Brunswick Acadian Forest. Can. J.
For. Res. 7:285-294.
Weller, M.W. 1979. Wetland habitats (theme paper).
Pages 210-234 in P.E. Greeson, J.R. Clark, and J.E.
Clark, eds. Wetland functions and values: the state of
our understanding. [Proc. natl. symp. on wetlands,
Lake Buena Vista, Fla., 1978] Am. Water Resour.
Assoc., Minneapolis, Minn.
Wells, E.D., and H.E. Hirvonen. 1988. Wetlands of Atlan-
tic Canada. Pages 249-303 in Natl. Wetlands Work-
ing Group. Wetlands of Canada. Ecol. Land
Classification Ser., No. 24. Sustainable Dev. Branch,
Environ. Can., Ottawa and Polyscience Publ. Inc.,
Montreal.
Wells-Gosling, N., and L.R. Heaney. 1984. Glaucomys
sabrinus. Mamm. Species 229:1-8.
Werner, R.A. 1983. Biomass, density, and nutrient content
of plant arthropods in the taiga of Alaska. Can. J. For.
Res. 13:729-739.
West, G.C., and B.B. DeWolfe. 1974. Populations and en-
ergetics of taiga birds near Fairbanks, Alaska. Auk
91(4):757-775.
West, S.D. 1977. Midwinter aggregation in the northern
red-backed vole, Clethrionomys rutilus. Can. J. Zool.
55:1404-1409.
. 1982. Dynamics of colonization and abundance in
central Alaskan populations of the northern red-
backed vole, Clethrionomys rutilus. J. Mammal.
63(1):128-143.
Wetzel, R.G. Limnology. Second ed. Saunders College
Publ., Harcourt Brace Johanovich College Publ.,
New York. 767pp. + refs. + appendices.
Whalen, S.C., and W.S. Reeburgh. 1992. Interannual
variations in tundra methane emission: a 4-year time
series at fixed sites. Global Biogeochem. Cycles
6(2): 139-159.
, , and K.S. Kizer. 1991. Methane consump-
tion and emission by taiga. Global Biogeochem.
Cycles 5(3):261-273.
Whigham, D.F., and S.E. Bayley. 1979. Nutrient dynam-
ics in fresh water wetlands. Pages 468-478 in P.E.
Greeson, J.R. Clark, and J.E. Clark, eds. Wetland
functions and values: the state of our understanding.
[Proc. natl. symp. on wetlands, Lake Buena Vista,
Fla., 1978] Am. Water Resour. Assoc., Minneapolis,
Minn.
Whitaker, J.O., Jr. 1972. Zapus hudsonius. Mamm. Spe-
cies 11:1-7.
White, C.M. 1982. Food and other habits in relation to the
evolution of the peregrine falcon in Alaska. Pages
174-186 in W.N. Ladd and P.P. Schempf, eds. Proc.
of a symposium and workshop on raptor manage-
ment and biology in Alaska and western Canada.
U.S. Fish Wildl. Serv., Alaska Reg. Off., FWS/AK7
PROC-82.
, and J.R. Haugh. 1969. Recent data on summer
birds of the upper Yukon River, Alaska, and adjacent
part of the Yukon Territory, Canada. Can. Field-Nat.
83:257-271.
White, R.G., B.R. Thomson, T. Skogland, S.J. Person,
D.E. Russell, D.F. Holleman, and J.R. Luick. 1975.
Ecology of caribou at Prudhoe Bay, Alaska. Pages
150-201 in J. Brown, ed. Ecological investigations of
the tundra biome in the Prudhoe Bay Region, Alaska.
Biol. Pap. Univ. Alaska Spec. Rep. No. 2, Fairbanks.
Whitney, P., and D. Feist. 1984. Abundance and survival
of Clethrionomys rutilus in relation to snow cover in
a forested habitat near College, Alaska. Pages 113-
119 in J.F. Merritt, ed. Winter ecology of small mam-
mals. Spec. Publ. Carnegie Mus. Nat. Hist. No. 10.
Pittsburgh, Pa.
Wieder, R.K. 1990. Metal cation binding to Sphagnum
peat and sawdust: relation to wetland treatment of
metal-polluted waters. Water, Air, and Soil Pollut.
53:391-400.
Wiegers, J. 1990. Forested wetlands in western Europe.
Pages 407-436 in A.E. Lugo, S. Brown, and M.
Brinson, eds. 15. Forested wetlands. Elsevier Sci.
Publ. Co., Amsterdam.
Wilk, R.J. 1993. Observations on sympatric tundra, Cyg-
nus columbianus, and trumpeter swans, C. buccina-
tor, in north-central Alaska, 1989-1991. Can.
Field-Nat. 107(l):64-68.
Williams, J.R., and R.M. Waller. 1963. Ground water oc-
755
-------
Functional Profile of Black Spruce Wetlands in Alaska
currence in permafrost regions of Alaska. Pages 159-
164 in Int. Conference on Permafrost, Lafayette, Ind.,
1963. [Proc.] Natl. Acad. Sci. Natl. Res. Counc.
Publ. No. 1287, Washington, D.C.
Willner, G.R., G.A. Feldhamer, E.E. Zucker, and J.A.
Chapman. 1980. Ondatra zibethic us. Mamm. Species
141:1-8.
Wilson, D.E. 1982. Wolverine. Pages 644-652 in J.A.
Chapman and G.A. Feldhamer, eds. Wild mammals
of North American: biology, management, and eco-
nomics. Johns Hopkins Univ. Press, Baltimore and
London.
Wolff, J. O. 1978a. Food habits of snowshoe hares in in-
terior Alaska. J. Wildl. Manage. 42(1): 148- 153.
_ . 1978ft. Burning and browsing effects on willow
growth in interior Alaska. J. Wildl. Manage.
42(1):135-140.
_ 1980. The role of habitat patchiness in the popu-
lation dynamics of snowshoe hares. Ecol. Monogr.
, C.T. Cushwa, and K.P. Burnham. 1979. Habitat
utilization by snowshoe hares in burned and un-
burned black spruce communities. Pages 57-63 in
L.A. Viereck and C.T. Dyrness, tech. eds. Ecological
effects of the Wickersham Dome fire near Fairbanks,
Alaska. U.S. For. Serv. Pac. Northwest For. Range
Exp. Stn. Gen. Tech. Rep. PNW-90.
, and W.Z. Lidicker, Jr. 1980. Population ecology of
the taiga vole, Microtus xanthognathus, in interior
Alaska. Can. J. Zool. 58:1800-1812.
, and _ . 1981. Communal winter nesting and
food sharing in taiga voles. Behav. Ecol. Sociobiol.
9:237-240.
Woo, M.K. 1986. Permafrost hydrology in North
America. Atmos.-Ocean 24(3):201-234.
1988. Wetland runoff regime in northern Canada.
Pages 644-649 in K. Senneset, ed. Int. Conference on
Permafrost (Fifth), Trondheim, Norway, 1988. [Proc.
Vol. 1] Tapir Publ., Trondheim.
, and J. Valverde. 1981. Summer streamflow and
water level in a midlatitude forested swamp. For. Sci.
27(1):177-189.
Wood, T.J. 1967. Ecology and population dynamics of the
red squirrel (Tamiasciurus hudsonicus) in Wood Buf-
falo National Park. M.A. Thesis, Univ.
Saskatchewan, Saskatoon. 97pp.
Woods, C.A. 1973. Erethizon dorsatum. Mamm. Species
29:1-6.
Wright, R.K. 1979. Preliminary results of a study on ac-
tive layer hydrology in the discontinuous zone at
Schefferville, Nouveau-Quebec. Geogr. phys. Quat.
33(3-4):359-368.
Wrigley, R.E., I.E. Dubois, and H.W.R. Copland. 1979.
Habitat, abundance, and distribution of six species of
shrews in Manitoba. J. Mammal. 60(3):505-520.
Yarie, J. 1983. Environmental and successional relation-
ships of the forest communities of the Porcupine
River drainage, interior Alaska. Can. J. For. Res.
13(5):721-728.
Youngman, P.M. 1975. Mammals of the Yukon Territory.
Natl. Mus. Nat. Sci. Publ. Zool. No. 10., Natl. Mus.
Can., Ottawa. 192pp.
Zachel, C.R. 1985. Food habits, hunting activity, and post-
fledging behavior of northern goshawks (Accipiter
gentilis) in interior Alaska. M.S. Thesis. Univ.
Alaska, Fairbanks. 81pp.
Zasada, J. 1976. Ecological and silvicultural consider-
ations: Alaska's interior forests. J. For. 74(6):334-
337.
. 1986. Natural regeneration of trees and tall shrubs
on forest sites in interior Alaska. Pages 44-73 in K.
Van Cleve, F.S. Chapin, III, P.W. Flanagan, L.A.
Viereck, and C.T. Dyrness, eds. Forest ecosystems in
the Alaskan taiga. Springer-Verlag, New York.
, R.A. Norum, R.M. Van Veldhuizen, and C.E.
Teutsch. 1983. Artificial regeneration of trees and tall
shrubs in experimentally burned upland black spruce/
feather moss stands in Alaska. Can. J. For. Res.
13:903-913.
Zenone, C. 1976. Geohydrology of the lowland lakes
area, Anchorage, Alaska. U.S. Geol. Surv. Water
Resour. Invest. WRI 76-22. 2 sheets.
Zoladeski, C.A., and P.P. Maycock. 1990. Dynamics of
the boreal forest in northwestern Ontario. Am. Mid-
land Nat. 124(2):289-300.
Zoltai, S.C. 1972. Palsas and peat plateaus in central
Manitoba and Saskatchewan. Can. J. For. Res. 2:291-
302.
. 1973. The range of tamarack (Larix laricina (Du
Roi) K. Koch) in northern Yukon Territory. Can. J.
For. Res. 3:461-464.
. 1975. Tree ring record of soil movements on per-
mafrost. Arct. and Alpine Res. 7(4):331-340.
. 1988. Wetland environments and classification.
Pages 1-26 in Natl. Wetlands Working Group. Wet-
lands of Canada. Ecol. Land Classification Sen, No.
24. Sustainable Dev. Branch, Environ. Can., Ottawa
and Polyscience Publ. Inc., Montreal.
. 1993. Cyclic development of permafrost in the
peatlands of northwestern Alberta, Canada. Arct. and
Alpine Res. 25(3):240-246.
, and J.D. Johnson. 1987. Relationships between
nutrients and vegetation in peatlands of the prairie
provinces. Pages 535-542 in C.D.A. Rubec and R.P.
Overend, compilers. Proc. Symposium '87 Wetlands/
Peatlands, Edmonton, Alta., 1987.
, and F.C. Pollett. 1983. Wetlands in Canada: their
classification, distribution, and use. Pages 245-268 in
154
-------
Literature Cited
A.J.P. Gore, ed. 4B. Mires: swamp, bog, fen and
moor regional studies. Elsevier Sci. Publ. Co.,
Amsterdam.
, and C. Tarnocai. 1975. Perennially frozen
peatlands in the western Arctic and Subarctic of
Canada. Can. J. Earth Sci. 12(l):28-43.
_, , G.F. Mills, and H. Veldhuis. 1988. Wet-
lands of subarctic Canada. Pages 55-96 in Natl. Wet-
lands Working Group. Wetlands of Canada. Ecol.
Land Classification Ser., No. 24. Sustainable Dev.
Branch, Environ. Can., Ottawa and Polyscience Publ.
Inc., Montreal.
, S. Taylor, J.K. Jeglum, G.F. Mills, and J.D.
Johnson. 1988. Wetlands of boreal Canada. Pages 97-
154 in Natl. Wetlands Working Group. Wetlands of
Canada. Ecol. Land Classification Ser, No. 24. Sus-
tainable Dev. Branch, Environ. Can., Ottawa and
Polyscience Publ. Inc., Montreal.
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Functional Profile of Black Spruce Wetlands in Alaska
APPENDIX A
WETLAND CLASSIFICATION
Circumboreal mire vegetation is similar, espe-
cially in bogs (Sjors 1963 in Moore and Bellamy
1974:181, Sorenson 1948 in Moore and Bellamy
1974:181), as is mire morphology. For example,
Sphagnum magellanicum and 5. papillosum charac-
terize nutrient-poor mires in the Amur River valley
(Botch and Masing 1983); both species also occur in
North American wetlands (Vitt et al. 1988:53). Aapa
mires (patterned mires) and palsa mires (wetlands
containing ice-cored mounds) occur in Fennoscandia
(Moore and Bellamy 1974:12-30, Sjors 1983, Eurola
et al. 1984), Siberia (Botch and Masing 1983), and
North America (Moore and Bellamy 1974:44,182).
Pleistocene glaciation influenced formation of many
taiga wetlands, as well (Strahler 1963:532-533,
Zoltai and Pollett 1983, Masing 1984, Hollis and
Jones 1991).
Despite widespread similarities of peatland veg-
etation and morphology, many methods of classifi-
cation have been described, often on a
country-by-country basis (e.g., Cowardin et al. 1979,
Ruuhijarvi 1983, Sjors 1983, Zoltai and Pollett 1983,
Moore 1984). Two broad-based wetland classifica-
tion systems apply to boreal regions of North
America: the U.S. Fish and Wildlife Service system
(Cowardin et al. 1979) and the Canadian system
(Natl. Wetlands Working Group 1988).
U.S. FISH AND WILDLIFE
SERVICE SYSTEM
The National Wetlands Inventory of the U.S. Fish
and Wildlife Service classifies and maps wetlands in
the United States using the hierarchical system of
Cowardin et al. (1979). The classification is divided
into five systems at its broadest level: Marine, Estua-
rine, Riverine, Lacustrine, and Palustrine. Sub-
systems, classes, subclasses, and dominance types
are successively narrower classification divisions.
This report addresses selected wetlands in the
Palustrine System.
Vegetated (>30% cover of trees, shrubs, persis-
tent emergents, emergent mosses, or lichens), fresh-
water (<0.5%o ocean-derived salts) wetlands
generally form the Palustrine System. Small (<8 ha),
shallow (<2 m), sparsely-vegetated freshwater wet-
lands lacking wave-formed or bedrock shorelines
also are palustrine. No subsystems are used to clas-
sify palustrine habitats. Eight classes based on domi-
nant life form occur within the Palustrine System,
three of which are relevant to BSWs: Emergent
Wetland, Scrub-Shrub Wetland, and Forested Wet-
land.
Forested Wetland must have >30% areal cover of
tall >6 m) woody vegetation. Areas with <30% cover
by woody vegetation >6 m in height, but with >30%
total cover by woody vegetation are Scrub-Shrub
Wetland. Needle-leaved Evergreen, Broad-leaved
Evergreen and Broad-leaved Deciduous are sub-
classes of Forested Wetland and Scrub-Shrub Wet-
land.
Rooted herbaceous vegetation standing above the
surface of periodically wet soil or water forms the
Emergent Wetland Class. Mosses and lichens form a
separate stratum and are not included in this class.
Subclasses of Emergent Wetland are Persistent and
Nonpersistent based on whether or not the plants
remain standing between growing seasons.
CANADIAN SYSTEM
The Canadian system of wetland classification
uses three hierarchical levels: class, form, and type
(Natl. Wetlands Working Group 1988:416). Bog,
756
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Appendix A
fen, swamp, marsh, and shallow open water are the
five wetland classes used in the Canadian system.
This system subdivides bogs into 18 wetland forms,
fens into 17 forms, swamps into 7 forms, marshes
into 15 forms, and shallow water into 13 forms
(Zoltai 1988). The third hierarchical level of the sys-
tem uses eight general physiognomic types of veg-
etation (treed, shrub, forb, graminoid, moss, lichen,
aquatic, and nonvegetated) as descriptors of wetland
forms. Specific types (e.g., "coniferous treed," "tall
shrub," or "sedge") occur within several of the gen-
eral types (Natl. Wetlands Working Group
1988:426).
Wetland scientists divide Canada into wetland re-
gions and subregions (Natl. Wetlands Working
Group 1986). Two of these regions, the Subarctic
and Boreal, encompass the taiga and thus much of
the distribution of black spruce. Within the Subarc-
tic and Boreal wetland regions of Canada, bogs and
fens are the wetland classes supporting black spruce
or closely associated with BSWs.
757
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Functional Profile of Black Spruce Wetlands in Alaska
APPENDIX B
SUBARCTIC AND BOREAL BOGS AND FENS
IN THE CANADIAN CLASSIFICATION SYSTEM
The following text quotes physical descriptions
of subarctic and boreal bog and fen characteristics
from the National Wetlands Working Group
(1988:417-420) and summarizes descriptions of veg-
etation from Zoltai, Tarnocai et al. (1988) and Zoltai,
Taylor et al. (1988). Black spruce wetlands of Alaska
presumably share some of the characteristics of
comparable wetlands described for Canada.
BOGS
Basin Bog - A bog situated in a basin that has an es-
sentially closed drainage, receiving water from
precipitation and from runoff from the immedi-
ate surroundings. The surface of the bog is flat,
but the peat is generally deepest at the centre.
Basin bogs occur in the Boreal Wetland Region.
Vegetation may include black spruce, Labrador-
tea, leatherleaf, bog kalmia, cotton grass,
Smilacina trifolia, cloudberry, Sphagnum
fuscum, S. magellanicum, and S. fallax.
Collapse Scar Bog - A circular or oval-shaped wet
depression in a perennially frozen peatland. The
collapse scar bog was once part of the perenni-
ally frozen peatland, but the permafrost thawed,
causing the surface to subside. The depression is
poor in nutrients, as it is not connected to the
minerotrophic fens in which the palsa or peat
plateau occurs.
Domed Bog - A large (usually more than 500 m in di-
ameter) bog with a convex surface, rising sev-
eral metres above the surrounding terrain. The
centre is usually draining in all directions. Small
crescentic pools often form around the highest
point. If the highest point is in the centre, the
pools form a concentric pattern, or eccentric if
the pattern is off-centre. Peat development is
usually in excess of 3 m. Vegetation of domed
bogs, which occur in the southeastern portion of
the Boreal Wetland Region, include black spruce
and tamarack, at least on portions of the dome,
with leatherleaf, Labrador-tea, and bog kalmia in
the shrub layer. Sphagnum nemoreum, S.
fuscum, and Pleurozium schreberi may be
present as ground cover.
Flat Bog - A bog having a flat, featureless surface. It
occurs in broad, poorly defined depressions. The
depth of peat is generally uniform. Flat bogs oc-
cur in the northern (High) portion of the Boreal
Wetland Region. Vegetation may include black
spruce, leatherleaf, bog kalmia, Labrador-tea,
cloudberry, Smilacina trifolia, Sphagnum
fuscum, S. fallax, S. ang'ustifolium, and occa-
sionally lichens (Cladina spp.) on elevated peat
surfaces.
Northern Plateau Bog - A raised bog elevated 0.5-1
m above the surrounding fen. The surface is gen-
erally even, characterized only by small wet
depressions. The plateau bog is usually teardrop-
shaped, with the pointed end oriented in the
down-slope direction. Northern plateau bogs
form in the Continental High Boreal Wetland
Region. Vegetation may include black spruce,
Labrador-tea, leatherleaf, Kalmia angustifolia,
cloudberry, mountain-cranberry, bog cranberry,
Sphagnum fuscum, and lichens.
Palsa Bog A bog composed of individual or coa-
lesced palsas, occurring in an unfrozen peatland.
Palsas are mounds of perennially frozen peat
and mineral soil, up to 5 m high, with a maxi-
mum diameter of 100 m. The surface is highly
uneven, often containing collapse scar bogs.
Palsa bogs occur in the Subarctic and Boreal
158
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Appendix B
wetland regions. Vegetation may include sparse
black spruce, narrow-leaf Labrador-tea (Ledum
decumbens), and cloudberry, but lichens such as
Cetraria spp. and Cladina spp. dominate the
ground surface.
Peat Plateau Bog - A bog composed of perennially
frozen peat, rising abruptly about 1 m from the
surrounding unfrozen fen. The surface is rela-
tively flat and even, and often covers very large
areas. The peat was originally deposited in a
nonpermafrost environment and is often associ-
ated with collapse scar bogs or fens. Peat plateau
bogs occur in the Subarctic and Boreal wetland
regions. Vegetation may include black spruce,
narrow-leaf Labrador-tea, Labrador-tea, bog-
rosemary, resin birch, mountain-cranberry,
cloudberry, and lichen ground cover (Cladina
spp., Cladonia amaurocraed). Sphagnum spp.
sometimes are present in newly forming mats
adjacent to existing peat plateaus or in collapse
scars on bog surfaces. Additional species such as
willow, paper birch, leatherleaf, cotton grass,
sedge, feathermosses, and Sphagnum spp. occur
on peat plateaus in the Boreal Wetland Region.
Polygonal Peat Plateau Bog - A perennially frozen
bog, rising about 1 m above the surrounding fen.
The surface is relatively flat, scored by a polygo-
nal pattern of trenches that developed over ice
wedges. The permafrost and ice wedges devel-
oped in peat originally deposited in a
nonpermafrost environment. Polygonal peat pla-
teau bogs, similar to peat plateau bogs, are found
in the Subarctic Wetland Region. As in the latter
wetlands, lichens (Cladina spp., Cetraria spp.,
andAlectoria sp.) dominate the ground cover of
these elevated surfaces. Vegetation may also in-
clude resin birch, Labrador-tea, and krummholz
forms of black spruce; wet polygon trenches
may support Sphagnum fuscum.
Veneer Bog - A bog occurring on gently sloping ter-
rain underlain by generally discontinuous per-
mafrost. Although drainage is predominantly
below the surface, overland flow occurs in
poorly defined drainage-ways during peak run-
off. Peat thickness is usually less than 1,5 m.
Veneer bogs develop in the Low Subarctic and
High Boreal wetland regions. Larger, more di-
verse vegetation in runnels on the veneer bog
surface may include black spruce, tamarack,
paper birch, resin birch, Alnus rugosa, American
green alder, sedges, and mosses. In contrast,
black spruce, Labrador-tea, narrow-leaf Labra-
dor-tea, cloudberry, leatherleaf, feathermosses
(Pleurozium schreberi, Hylocomium splendens),
and Sphagnum fuscum hummocks characterize
vegetation in interrunnel areas. Lichens
(Cladina spp.) occur in the ground cover.
FENS
Basin Fen A fen occupying a topographically de-
fined basin. However, the basins do not receive
drainage from upstream and the fens are thus
influenced mainly by local hydrologic condi-
tions. The depth of peat increases towards the
centre. Basin fens occur in the Boreal Wetland
Region of Canada. Vegetation on the surface of
these fens may include tamarack, Betula pumila,
Carex aquatilis, Sphagnum angustifolium, C.
lasiocarpa, Drepanocladus exannulatus, D.
revolvens, Campylium stellatum, Calliergon
giganteum, and C. richardsonii; but bulrush,
cattail, willow, and bluejoint (Calamagrostis
canadensis) occur at fen margins.
Channel Fen - A fen occurring in a topographically
well-defined channel which at present does not
contain a continuously flowing stream. The
depth of peat is usually uniform. Channel fens
are found in the Subarctic Wetland Region. Veg-
etation may include tamarack, resin birch, wil-
low, Scirpus hudsonianus, Scheuchzeria
palustris, Rhynchospora alba, Carex limosa,
Sphagnum fuscum, Tomenthypnum nitens, and
Pleurozium schreberi.
Collapse Scar Fen A fen with circular or oval de-
pressions, up to 100 m in diameter, occurring in
larger fens, marking the subsidence of thawed
permafrost peatlands. Dead trees, remnants of
the subsided vegetation of permafrost peatlands,
are often evident.Collapse scar fens occur in the
Subarctic and Boreal wetland regions. Vegeta-
tion may include stunted black spruce, willow,
leatherleaf, resin birch, Vaccinium myrtilloides,
sedges, Sphagnum spp., feathermosses, and
Drepanocladus spp. at the periphery with
sedges, wild calla (Calla palustris), and mosses
(Drepanocladus spp., Calliergon cordifolium) in
the wetter center.
Feather Fen - A fen situated on a long, narrow ridge
159
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m
Functional Profile of Black Spruce Wetlands in Alaska
of mineral soil. The centre of the ridge is occu-
pied by a bog, but many narrow, subparallel
drainage-ways originate from the ridge and are
occupied by a feather fen. Water from the fen
drainage-ways is usually collected by a stream
running parallel to the ridge. The average depth
of peat is 1.5 m. Feather fens are found in the
Boreal Wetland Region. Although black spruce,
leatherleaf, and Sphagnum spp. may be present
in the closely associated ridgetop bogs, vegeta-
tion of the feather fens may include tamarack, a
number of sedge species, and Sphagnum
warnstorfii. Black spruce swamps may occur
along streams between feather fen ridges.
Horizontal Fen A fen with a very gently sloping
featureless surface. This fen occupies broad, of-
ten ill-defined depressions, and may be intercon-
nected with other fens. Peat accumulation is
generally uniform. Horizontal fens occur in the
Boreal Wetland Region. Bog formations can be
present as black spruce "islands" within the fen.
Fen vegetation may include tamarack, Betula
pumila, buckthorn, bulrushes, swamp horsetail,
sweetgale, sedges, cotton grass, Habenaria
dilatata, buckbean, and mosses (Sphagnum
teres, S. warnstorfii, S. fallax, Campylium
stellatum, Drepanocladus revolvens, and
Scorpidium scorpiodes).
Northern Ribbed Fen - A fen with parallel, low peat
ridges ("strings") alternating with wet hollows
or shallow pools, oriented across the major slope
at right angles to water movement. The depth of
peat exceeds 1 m. Northern ribbed fens are
found in the Subarctic and Boreal wetland re-
gions. Vegetation of flarks may include sedges,
buckbean, Utricularia spp., arrow grass, cotton
grass and mosses (Scorpidium scorpioides,
Drepanocladus revolvens, Meesia triquetra,
Pohlia sp. and Cinclidium stygium); Sphagnum
balticum and S. compactum form "lawns"
around flarks. Vegetation on low, wet strings
may include resin birch, Betula pumila, willows,
bog-rosemary, sedges, and mosses
(Tomenthypnum nitens, Campylium stellatum,
and Sphagnum warnstorfii). Tamarack, Betula
pumila, Labrador-tea, narrow-leaf Labrador-tea,
bog kalmia, leatherleaf, bog-rosemary, Sphag-
num warnstorfii, S.fuscum, and Tomenthypnum
nitens may occur on strings of intermediate
height. The highest ridges support black spruce,
tamarack, Betula pumila, Labrador-tea, leather-
leaf, Carex disperma, Sphagnum fuscum, S.
magellanicum, Pleurozium schreberi, Dicranum
undulatum, and lichens (Cladina spp.). Strings
may form peat plateau bogs if sufficiently el-
evated by permafrost to become ombrotrophic.
Spring Fen - A fen nourished by a continuous dis-
charge of groundwater. The surface is marked by
pools, drainage tracks, and, occasionally, some-
what elevated "islands." The nutrient level of
water is highly variable between locations.
Spring fens develop in the Boreal Wetland Re-
gion. Vegetation may include Carex lasiocarpa,
C. interior, C. limosa, Scirpus caespitosus,
Eleocharis quinqueflora, Scorpidium
scorpioides, Drepanocladus revolvens, and
Campylium stellatum. Treed "islands," poten-
tially supporting black spruce, occur in less
minerotrophic areas of spring fens.
Palsa Fen - A fen with mounds of perennially frozen
peat (sedge and brown moss peat) and mineral
soil, up to 5 m high and 100 m in diameter al-
though they can be much smaller. Palsa fens
generally occur in unfrozen peatlands and are
frequently associated with collapse scar fens.
760
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APPENDIX C
PHYSICAL DESCRIPTIONS OF REPRESENTATIVE
BLACK SPRUCE COMMUNITY TYPES OF ALASKA
The following physical descriptions of black
spruce community types are quoted from Foote
(1983:29-48).
PICEA MARIANA/SPHAGNUM SPR-
CLADINA SPP. COMMUNITY TYPE
Stands typifying this community type occur on
valley bottoms or on north-facing slopes where ice-
rich permafrost is present and a perched water table
is common. A surface horizon of organic material
0.3 m to over 1 m thick overlies loess or valley allu-
vium. Soils on these sites are cool and moist. Surface
soils melt to a depth of 30 cm by late June and 60 cm
by August. Excess water from melting frozen soil
and precipitation collects in low depressions and
thaw ponds or is absorbed by the mounds of Sphag-
num spp. which have very high water-holding ca-
pacities. The permafrost layer prevents the
downward movement of water.
PICEA MARIANA/VACCINIUM
ULIGINOSUM-LEDUM GROENLANDICUM/
PLEUROZIUM SCHREBERI COMMUNITY
TYPE
Stands typifying this community type may be
found on all mesic black spruce sites; i.e., on both
slopes and valley bottoms whenever the soil is not
too wet. Usually a 5- to 25-cm-thick surface horizon
of organic material overlies a layer of loess, stony re-
sidual soil, or valley alluvium. Ice-rich permafrost is
generally present. The surface soil is kept cool and
moist by the permafrost below and the moss insula-
tion above. Surface soil temperatures increase
throughout the summer; the soil thaws to a depth of
30 cm by late June and to 50 cm by August.
PICEA MARIANA-BETULA PAPYRIFERA/
VACCINIUM ULIGINOSUM-LEDUM
GROENLANDICUM COMMUNITY TYPE
Stands typifying this community type can be
found wherever mesic black spruce sites occur; i.e.,
on slopes of all aspects or on valley bottoms where
a modest amount of drainage occurs. Permafrost
may or may not be present. By July the ground
thaws to a maximum depth of 50 cm. These sites,
therefore, may have slightly cooler soil temperatures
than sites where the Populus tremuloides-Picea
mariana/Cornus canadensis community type oc-
curs.
PICEA MAK/AM4/FEATHERMOSS-LICHEN
COMMUNITY TYPE
Stands typifying this community type occur
wherever black spruce sites are found; i.e., on slopes
of all aspects and gradients and on valley bottoms. A
surface horizon of organic material overlies loess,
weathered bedrock, or valley alluvium. The depth of
the organic layer varies from 5 cm in the lichen-
dominated openings to 20 cm in the moss and tree-
dominated areas. Permafrost may or may not be
present.
PICEA MARIANA-PICEA GL\UCA/BETUL\
GLANDULOSA/LICHEN COMMUNITY
TYPE
Stands typifying this community type occur on
east- or west-facing slopes above 700 m or near tim-
berline. These slopes are cool and dry to mesic. A
thin surface layer of organic material 0-3 cm thick
overlies stony soils and shallow bedrock.
161
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Functional Profile of Black Spruce Wetlands in Alaska
POPULUS TREMULOIDES-PICEA layer is shallow, about 12 cm, and overlies loess,
MARIANA/CORNUS CANADENSIS COMMU- bedrock, or river alluvium. By late June the seasonal
NITY TYPE soil frost melts to a depth of 50-60 cm, and by Au-
Stands typifying this community type occur on gust, when the seasonal frost is gone, pockets of
warm, well-drained black spruce sites; i.e., on slopes permafrost may occur 65 cm or more below the sur-
with southerly exposures or on slightly raised, better face.
drained areas on upland valley floors. The organic
762
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APPENDIX D
INTERPRETATION OF AVIAN SURVEYS
WITH RESPECT TO BLACK SPRUCE WETLAND HABITATS
Studies of bird distribution and abundance are
not always keyed to specific habitats or may be
keyed to habitat classification systems that do not
include BSWs. The following discussion and tables
present evidence for interpreting specific studies as
applying to BSWs. I also include studies of low/
medium shrub thicket habitats (tall shrub excluded)
because BSWs often include significant shrub com-
ponents in their understories, particularly when
sparsely treed. For conservatism, I interpret
"muskeg" as sparse "black spruce" without refer-
ence to wetland status. Common usage of this term
in the Interior usually connotes wetland, however.
ALASKA
Avian surveys that provide sufficient information
to draw inferences about bird use of BSWs in Alaska
include Spindler and Kessel (1980) in the eastern In-
terior (Table D-1), Cooper et al. (1991:279-280) near
Tok and Gulkana (Table D-2), Martin et al. (1995)
near Fairbanks (Table D-3), Spindler (1976) near
Fairbanks (Table D-4), and Kessel et al. (1982) near
the Susitna River at the boundary between the
Southern and Interior regions (Table D-5.).
Less specifically, Hogan and Tande (1983) sur-
veyed Anchorage mires, but data are not specific to
vegetation communities within mire complexes. I in-
terpret bird use of these areas as occurring in
"mires." West and DeWolfe (1974) and Kron (1975),
recorded bird observations on several trails through
a variety of taiga habitats near Fairbanks, and Coo-
per et al. (1991:284-290) observed birds (not associ-
ated with specific habitats) during spring and fall
migrations. I interpret bird observations on the trails
near Fairbanks and during migration in the eastern
Interior as occurring in a "mixed taiga landscape."
Heglund (1988, 1992) studied bird use of
waterbodies in the Yukon Flats. I interpret bird use
of waterbodies surrounded, or influenced, by BSWs
as showing a habitat relationship to those wetlands.
CANADA
Avian surveys in the taiga of northern Canada
that provide habitat-specific information include
Carbyn (1971) in the Northwest Territories (Table D-
6), Gillespie and Kendeigh (1982) in Manitoba
(Table D-7), and Erskine (1977) for all Canadian
boreal habitats (Table D-8). Larsen (1982:271) pro-
vides a table of breeding bird species for northern
bogs, defined as in this profile, which I interpret as
black spruce mires.
LOWER 48 STATES
An avian survey of Michigan "bogs," Ewert
(1982), applies to BSWs (Table D-9). Gibbs et al.
(1991) also provide habitat preferences of birds us-
ing Maine "bogs."
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Functional Profile of Black Spruce Wetlands in Alaska
Table D-l. Interpretation ofavian surveys by Spindler and Kessel (1980) in eastern interior Alaska with
respect to black spruce wetlands.
Plot or
Transect
Identifier
Black Spruce
"Bog" (two
plots)
Coniferous
Forest
(several plots)
Low and
Medium
Shrub Thicket
(<2.4 m in
height, three
plots)
Community Description
Black spruce with
Sphagnum mat or cotton
grass tussocks for ground
cover
Black spruce, tamarack
with Labrador-tea, bog
blueberry, Sphagnum in
lowland plots
Willows, shrub birches,
bog blueberry, leatherleaf,
Labrador-tea, cotton grass
tussocks
Wetland Indicators
Apparently on
permafrost, tamarack
(FACW) on one plot
Black spruce (FACW)
and tamarack
(FACW)
Wetland vegetation,
one plot was sedge
meadow
Comments
Trees <5 m in
height, cotton grass
site probably
minerotrophic
Both upland
(probably
nonwetland) and
lowland (probably
wetland) plots
Apparently
minerotrophic
wetlands
Name in
Black
Spruce
Profile
Black
Spruce
Wetland
Black
Spruce
Forest
Shrub
Thicket
Table D-2. Interpretation of breeding bird surveys by Cooper et al. (1991:279-280) near Tok and
Gulkana, Alaska, with respect to black spruce wetlands.
Plot or Transect
Identifier
Black Spruce
(several plots)
Medium-Low
Shrub Thicket (all
<4 m, presumably
most <2.4 m)
Community
Description
Black spruce with
ericaceous shrubs,
mosses, lichens, and
cotton grass tussocks
Willows, shrub birch,
cotton grass
Wetland Indicators
Boggy, poorly drained
soils, wetland
vegetation, numerous
pools of standing water
in one plot
Moist to wet meadow
Comments
High
probability of
being wetland
At least
partially
wetland
Name in Black
Spruce Profile
Black Spruce
Wetland
Shrub Thicket
164
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Appendix D
Table D-3. Interpretation of breeding bird surveys by Martin et al. (1995) in the Badger Slough watershed
near Fairbanks, Alaska, with respect to black spruce wetlands.
Plot or Transect
Identifier
Coniferous Forest
(multiple sample
points)
Intermediate/ Low
Shrub Thicket (<2.4
m in height, multiple
sample points)
• Community
Description
Tamarack,
black spruce,
white spruce
Not described,
presumably
willows and
shrub birch
Wetland
Indicators
Tamarack
(FACW), black
spruce (FACW),
discontinuous
permafrost
Study area mainly
wetland
Comments
Probably most black
spruce-tamarack plots
are wetland and plots
with white spruce are
nonwetland
Same vegetation
classification as
Spindler and Kessel
(1980)
Name in
Black Spruce
Profile
Black Spruce
Forest
Shrub Thicket
Table D-4. Interpretation of avion habitat studies by Spindler (1976) on the Fairbanks Wildlife Manage-
ment Area with respect to black spruce wetlands.
Plot or
Transect
Identifier
Black
Spruce
Tussock-
Low
Shrub
"Bog"
(actual
heights not
given)
Community Description
Black spruce, tamarack, white
spruce, resin birch, willows,
thinleaf alder (Alnus tenuifolia).
bog cranberry, mountain
cranberry, bog blueberry,
Labrador-tea, cloudberry,
bluejoint, Sphagnum, lichens
Paper birch (sparse), thinleaf alder
(sparse), black spruce (sparse),
willows, dwarf arctic birch,
mountain cranberry, bog
blueberry, Labrador-tea, bluejoint.
cotton grass, cloudberry,
Sphagnum, lichens
Wetland
Indicators
Mean depth to
permafrost <0.5 m.
saturated above
permafrost table,
fibric peat soil to
>1 m, marshy areas
present
Mean depth to
permafrost <0.5 m,
ice-wedge
polygons, peaty
soil >1 m, one pit
entirely sapric peat
Comments
Sample plot
predominantly
wetland
Gradient from cotton
grass to Sphagnum
and ericaceous
shrubs, sparse black
spruce in some
communities;
predominantly
wetland
Name in
Black
Spruce
Profile
Black
Spruce
Mire
Shrub
Mire
Table D-5. Interpretation ofavian surveys by Kessel et al. (1982) near the Susitna River. Alaska, with
respect to black spruce wetlands.
Plot or
Transect
Identifier
Black
Spruce
Dwarf
Forest
Community Description
Black spruce, bog blueberry,
mountain cranberry, crowberry
(Empetrum nigrum), Labrador-
tea, shrub birches, moss
Wetland Indicators
Water seepage through
plot, some hummocky
ground, stunted trees (2.9
m high at 80 yr)
Comments
Highly
probable
wetland
Name in
Black
Spruce
Profile
Black Spruce
Wetland
765
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Functional Profile of Black Spruce Wetlands in Alaska
Table D-6. Interpretation ofavian survey plots used by Carbyn (1971) in Northwest Territories, Canada,
with respect to black spruce wetlands.
Plot or
Transect
Identifier
Plot 2
PlotS
Plot 4
PlotS
Community
Description
Black spruce/
feathermoss
surrounding a "sedge
marsh"
Black spruce/ lichen,
buffaloberry, Potentilla
fruticosa, resin birch,
Labrador-tea
Similar to Plot 2
Open black
spmct/Sphagnum bog
with hummocks
Wetland Indicators
Tamarack (FACW),
black spruce
(FACW), several
shrub species (FAC)
Mossy depressions
Similar to Plot 2
Predominantly
FACW and FAC
shrub layer
Comments
Moisture gradient
between marsh and white
spruce on high ground
within plot
Nonwetland
Wetland status uncertain
Clearly a wetland
Name in Black
Spruce Profile
Black Spruce
Forest
Black Spruce
Forest
Black Spruce
Forest
Black Spruce
Mire
Table D-7. Interpretation ofavian surveys by Gillespie and Kendeigh (1982) in Manitoba, Canada, with
respect to black spruce wetlands.
Plot or
Transect
Identifier
Herriot
Creek Forest
Plot
Herriot
Creek
Forest-Edge
Plot
Gillam
Forest-Edge
Plot
Community
Description
Black spruce, white
spruce, tamarack, resin
birch, willow, alder
Alder, willow, shrub
birch
Black spruce scrub with
scattered tamarack,
willow, alder, Labrador-
tea, cloudberry, sedges
Wetland
Indicators
"Bog" meadows,
open water,
Sphagnum
hummocks
Riparian strip with
sedges and
sweetgale
Peat mounds,
water-filled
depressions, no
upland species
Comments
Site appears
predominantly wetland
with drier areas
Dense shrubs <2.3 m in
height, adjacent to spruce-
tamarack stand
Clearly wetland
Name in
Black
Spruce
Profile
Black
Spruce
Wetland
Shrub
Thicket
Black
Spruce
Wetland
766
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Appendix D
Table D-8. Interpretation of descriptions by Erskine (1977) of avion habitat use in boreal Canada.
Plot or
Transect
Identifier
Spruces
Bog Forest
Fen
Bogs
Community Description
Predominantly black
spruce with white spruce
and balsam fir (eastern
boreal forest)
Predominantly tamarack
with black spruce and
alder
None given
Black spruce, tamarack,
ericaceous shrubs, shrub
birches, willows, sedges,
sweet gale, peatmosses
Wetland Indicators
None
Dominants (FACW)
occurring on wet ground,
often around depressions
and in swales
Water table at surface
Wet sites, may include
open water
Comments
Nonwetland
Probably
wetland
Minerotrophic
wetland
structurally
similar to open
bog
Ombrotrophic
to weakly
minerotrophic
wetland
Name in Black
Spruce Profile
Black Spruce
Forest
Black Spruce
Wetland
Fen (Mire)
Black Spruce
Mire or Shrub
Mire (depending
on vegetation)
Table D-9. Interpretation ofavian surveys by Ewert (1982) in Michigan "bogs" with respect to black
spruce wetlands.
Plot or
Transect
Identifier
Black
Spruce-
Tamarack
"Bog"
Open
"Bog" (two
sites)
Community Description
Black spruce, tamarack,
Andromeda glaucophylla,
leatherleaf, bog kalmia,
Vaccinium sp., Labrador- tea,
Sphagnum, cotton grass
Leatherleaf, Andromeda
glaucophylla, bog kalmia,
Vaccinium sp., Sphagnum,
cotton grass
Wetland Indicators
Hummocks, small pools
(<1 m diameter) of
standing water,
surrounded by open peat
mat
Hummocks, small pools
(<1 m diameter) of
standing water
Comments
Wetland, trees
<8 m in height
Wetland, high
coverage by low
ericaceous
shrubs
Name in
Black
Spruce
Profile
Black
Spruce
Mire
Shrub Mire
767
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Functional Profile of Black Spruce Wetlands in Alaska
GLOSSARY
Acrotelm: The highly permeable, aerobic, partly liv-
ing upper organic layer of mires (Ingram 1983).
Active Layer: "The layer of ground above the per-
mafrost which thaws and freezes annually"
(Gabriel and Talbot 1984:7).
Api: Taiga snow characterized by little within-year
variability in thickness in a given region but
great between-year variability in thickness
(Pruitt 1978:12-14). Taiga snow usually has low
density and hardness except in exposed areas
like frozen lakes (Pruitt 1984).
Aufeis: "Sheets of ice formed by the freezing of
overflow water"; see naled (Gabriel and Talbot
1984:12).
Black Spruce Wetland (BSW): For purposes of this
report, a wetland containing black spruce of any
size or stand density.
Bog: A mire exclusively supplied by precipitation,
which typically has a low nutrient content (i.e.,
water that is oligotrophic), also known as an
ombrotrophic mire (Gore 1983, Gabriel and
Talbot 1984:77, Damman 1987).
Catotelm: Highly decomposed, anaerobic peat of
low hydraulic conductivity that underlies the
acrotelm (Ingram 1983).
Depression Storage: Water storage provided by to-
pographic depressions up to the depth at which
overflow occurs (i.e., depression storage must be
satisfied before runoff is initiated) (Woo 1986).
Detention Storage: Short-term water storage pro-
vided by topographic depressions filled to a
depth greater than the elevation of the surface
outlet (i.e., that portion of the stored water that
subsequently leaves the depression by surface
flow) (Woo 1986).
Ectothermic: Refers to organisms whose internal
temperatures largely are controlled by their en-
vironments.
Fen: A mire at least partly supplied by water that
contains moderate to high concentrations of nu-
trients (i.e., water that is mesotrophic or
eutrophic) from contact with mineral soil, also
known as a minerotrophic mire (Boelter and
Verry 1977, Gore 1983, Gabriel and Talbot
1984:71).
Fibric Peat: Undecomposed peat consisting of eas-
ily-identified plant parts.
Flarh: Wet depression oriented transverse to the di-
rection of flow and located between peat ridges
in a patterned peatland such as a northern ribbed
fen (Natl. Wetlands Working Group 1988:435).
Forest-Tundra: The transition zone between taiga
and tundra (Pruitt 1978:33) "characterized by a
mosaic of forest communities, krummholz, tree
islands, or trees growing along river and lake
shores or in sheltered positions, and a tundra
vegetation on exposed ridges between the rivers
and in xeric habitats" (Gabriel and Talbot
1984:47).
Histosol: "Soil that has organic materials in more
than half of the upper 32 in (80 cm) or of any
thickness if overlying bedrock" (Natl. Res.
Counc. 1995:286).
Hydric Soil: "A soil that is saturated, flooded, or
ponded long enough during the growing season
to develop anaerobic conditions in the upper
part" (Natl. Tech. Comm. Hydric Soils 1991:1).
Hydrophytes: "Macrophytic plant life growing in
water, soil, or on a substrate that is a[t] least pe-
riodically deficient in oxygen as a result of ex-
cessive water content" (Tiner 1989:17).
Ice Wedge: Massive structure ranging from 0.01 to
168
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Glossary
3 m in width and 1 to 10 m in height when
viewed in transverse section (i.e., end-on view)
and up to 15 m in length when viewed in longi-
tudinal section (i.e., face-on view) (Pewe
1975:49).
Krummholz: Stunted, scrubby, twisted growth forms
of species genetically capable of tree growth
(Gabriel and Talbot 1984:63).
Layering: Vegetative reproduction by rooting of
lower branches and growth of new individuals to
form a clone (Zasada 1986).
Microbivores: Organisms that feed on microbial
algae, bacteria, or fungi (MacLean 1980).
Minerotrophic: See fen.
Mire: A peat-forming ecosystem having >0.4 m peat
thickness, generally separated into bog and/en
based on vegetation, water source, and water
chemistry, all of which are related variables
(Boelter and Verry 1977, Gore 1983, Gabriel
and Talbot 1984:71-72, Zoltai 1988, Swanson
andGrigal 1989).
Muck: In common Alaska usage, a mixture of well-
decomposed organic material and mineral soil
(Gabriel and Talbot 1984:73).
Naled: "stream icing"; see aufeis (Gabriel and Tal-
bot 1984:75).
Ombrotrophic: See bog.
Palsa: Peat-covered mound or hummock from -0.1
to 10 m in height and from ~3 to 100 m in diam-
eter that contains a core of segregated ice and is
found in peatlands (Brown and Pewe 1973,
Pewe 1975:66, Kershaw and Gill 1979, Seppala
1982, Natl. Wetlands Working Group 1988:417-
420).
Paludification: The process of bog expansion over
forest, grassland, or bare rock that occurs as peat
accumulation impedes drainage (Gore 1983,
Nat]. Wetlands Working Group 1988:438).
Patterned Ground: The expression of an underlying
polygonal pattern of ice wedges on the surface
of the ground (Brown and Pewe 1973). Pat-
terned ground may also occur through intense
seasonal frost processes in nonpermafrost areas
with severely maritime climates and low mean
annual temperatures (Henderson 1968).
Peat Plateau: A raised permafrost feature with an in-
ternal structure similar to a palsa but having a
flat surface that may cover several square kilo-
meters (Kershaw and Gill 1979).
Peatland: See mire.
Permafrost: Soil, rock, or other substrates that con-
tinuously remain at temperatures below 0°C for
>2 yr (Brown and Pewe 1973).
Pingo: Large mound or hill ranging from 30 to 1,000
m in diameter and from 3 to 70 m in height and
containing massive ice heaved above the sur-
rounding landscape by artesian or hydrostatic
pressure (Holmes et al. 1963, Brown and Pewe
1973, Pewe 1975:56, Ferrians 1988).
Primary Mires: Those mires that occur with the
growth of peat-forming vegetation directly on
wet mineral soils (Sjors 1983).
Pukak: Depth hoar crystals that grow in a columnar
structure at the base of the snowpack and form
a subnivean space that provides a favorable mi-
croclimate for overwintering plants and animals
(Pruitt 1984).
Redoximorphic Features: Patterns of color related
to chemical reduction or oxidation of iron or
manganese (J. Bouma, Rep. of Int. Comm. on
Aquic Soil Moisture Regimes, Circular 10).
Redox Potential: Potentiometric measure of the oxi-
dizing or reducing intensity of a solution (Wetzel
1983:298).
Sapric Peat: Highly-decomposed peat (muck) in
which individual plant fibers are not visible.
Saprovores: Organisms that directly consume de-
caying organic matter.
Semiserotinous Cones: Cones that disseminate seed
over several years or longer after seed matura-
tion (Gabriel and Talbot 1984, Zasada 1986).
String: Peat ridge oriented transverse to the direction
of flow in a patterned wetland such as a northern
ribbed fen (Natl. Wetlands Working Group
1988:441).
Subpermafrost Groundwater: Water that is con-
fined beneath a layer of permafrost.
Suprapermafrost Groundwater: Water that occu-
pies the saturated portion of the active layer
above the permafrost table.
Taiga: "The wooded vegetation of boreal-subarctic
latitudes that occupies the subarctic climatic
zone adjacent to the treeless tundra" (Gabriel
and Talbot 1984:112).
Talik: Thawed zone within, or extending through,
permafrost, often beneath a waterbody, that can
connect suprapermafrost groundwater and
subpermafrost groundwater (Gabriel and Tal-
769
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Functional Profile of Black Spruce Wetlands in Alaska
hot 1984:112, Woo 1986).
Terrestrialization: The process whereby aquatic en-
vironments infill with peat (Sjors 1983).
Thaw Lake: Cave-in lake on flat or gently sloping
terrain underlain by fine-grained sediments that
forms when water ponds in a thermokarst de-
pression and promotes radial thaw and bank cav-
ing, which may continue for long periods of
time with eventual coalescence of thaw ponds
into larger lakes (Wallace 1948, Hopkins et al.
1955:140, Hopkins and Kidd 1988).
Thermokarst: The landscape features that result
when permafrost thaws and "creates an uneven
topography which consists of mounds, sink-
holes, tunnels, caverns, short ravines, lake ba-
sins, and circular lowlands caused by melting of
ground ice" (Pewe 1975:65).
Wetland Function: A physical, chemical, or biologi-
cal process occurring in a wetland. Examples
include storage of water, denitrification, and
photosynthesis.
*U.S. GOVERNMENT PRINTING OFFICE: 1996-793-933
770
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