E PA/600/A-92/204
USE OF ECOREGIONS IN BIOLOGICAL MONITORING
Robert M. Hughes. ManTech Environmental Technology, Incorporated. U.S. EPA Environmental Research
Laboratory. 200 SW 35th Street. Corvallis, OR. 97333.
Steven A. Heiskary. Nonpoint Source Section. Minnesota Pollution Control Agency. 520 Lafayette Road.
Saint Paul, MN. 55155-3898.
William J. Matthews. Biological Station. University of Oklahoma. Star Route B. Kingston, OK. 73439.
Chris O. Yoder. Ecological Assessment Section. Ohio Environmental Protection Agency. 1800 WaterMark
Drive. Columbus, OH. 43266-0149.
In S.L. Loeb (ed.) Biological Monitoring of Freshwater Ecosystems. Lewis Publishers. Chelsea, Ml.
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INTRODUCTION
In order to better manage populations of lakes and streams it is useful to have some form of lake
and stream classification. Such classifications may be based on site-specific data or on some form of
regionalization generated from those or other data. The goal of any classification is to stratify variance,
and the greater the variance that a classification accounts for, the more useful it is. The process of
classification is iterative; as we learn more about aquatic ecosystems through site-specific monitoring and
theoretical advances, we can use that knowledge to improve our classification and thereby the quality of
our science and management.
in biological monitoring programs, particularly at the state, regional, or national level, an
appropriate geographic framework is useful for developing estimates of organisms likely to be collected
and conditions likely to be encountered. Such a framework is also useful for setting biological criteria,
for interpreting the relative health of the site, and for extrapolating the results of collections or samples to
a population of water bodies. State agencies, in particular, need a method to break a large complex set
of systems into rational units for management and for predicting the results of management actions.
Traditionally, aquatic biologists have used river basins to determine these frameworks.
As assemblage and water quality data bases and statistical software have become available, they
have been used to frame regions. When mapped, the ordination results often are interpreted from some
preconceived landscape level pattern, such as river basins (Hocutt and Wiley 1986), catchments
(Matthews and Robison 1988), or physiography (Pflieger 1971).
Others have compared aquatic ecosystem patterns with various environmental variables. Ross
(1963) showed a strong association between North American caddisfly species in small streams and
terrestrial biomes. Legendre and Legendre (1984) found climatic, geomorphic, and vegetation patterns
more useful than river basins for explaining fish distribution patterns in Quebec. Minshall et al. (1985)
concluded that regional patterns in climate, geology, and land use were necessary for appropriately
applying the river continuum concept across regional scales. Jackson and Harvey (1989), in a study of
available data from 286 lakes in the northern Great Lakes area of Ontario, found that fish faunas were
significantly correlated with geographical proximity, but not with lake area, maximum depth, or pH. They
proposed that the fauna! patterns were a function of differing post-glacial dispersal routes and climatic
regimes, Corkum (1989), examining benthic invertebrate data from 100 river sites in northwestern North
America, determined that drainage basin, physiographic region, and bedrock geology were more useful
for classifying the fauna than were environmental variables measured at the sites. In a study of five sites
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along each of three rivers in eastern Ontario, she concluded that macroinvertebrate assemblages
corresponded more with land use than with season, site location along the rivers, or drainage (Corkum
1990).
Recently, aquatic ecoregions, developed from a combination of landscape characteristics, have
been proposed as a framework for assisting water body managers (Omernik 1987, Hughes and Larsen
1988). Ecoregions are defined as mapped regions of relative homogeneity in land surface form, soil,
potential natural vegetation, and general land use. Ecoregions group water bodies that would be naturally
similar in the absence of permanent human settlements and thereby they stratify variability; such regions
are substantially less diverse than an entire nation or state. They have been shown to correspond to
statewide differences in fish and water quality in Ohio streams (Larsen et al. 1986, 1988); fish, water
quality, and physical habitat in Arkansas streams (Rohm et al. 1987); fish, macroinvertebrates, physical
habitat, and water quality in Oregon streams (Hughes et al. 1987, Whittier et al. 1988); water quality in
Minnesota lakes (Heiskary et al. 1987); and fish in Wisconsin streams (Lyons 1989).
The purpose of this paper is to (1) compare fish faunal regions and ecoregions, (2) summarize
the experiences of two states that use ecoregions as management units, and (3) summarize the concerns
of workshop participants about the use of ecoregions.
CORRESPONDENCE BETWEEN FISH FAUNAL REGIONS AND ECOREGIONS
Pflieger (1971) and Pflieger et al. (1981), using fish assemblage data from over 1600 localities,
described three fish faunal regions and a large river fauna for Missouri. Except for northwest Missouri,
their regions and Omernik's show considerable correspondence (Figure 1), possibly because both
frameworks are partly based on physiographic patterns.
Analyzing data from 410 stream sites, Hawkes et al. (1986) distinguished six major fish regions
delineated mostly by drainage in Kansas. These bear no resemblance to the six regions Omernik mapped
for the state (Figure 2). Hawkes et al. observe, however, that the Walnut Creek drainage (which is split
by an Omernik ecoregion) divides into two fish regions.
Using discriminant analysis of fish data from 350 stream sites, Bazata (1991) found that five fish
faunal regions were more appropriate than the seven ecoregions of Omernik. However, the reduced
number of faunal regions were obtained by combining two small portions of Omernik ecoregions with two
larger ecoregions (Figure 3).
2.
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Hughes et al. (1987) used available data from 9100 collections in 85 catchments to evaluate the
ability ot ecoregions, drainage basins, and physiographic regions to form ichthyogeographic regions.
They found that 2 of 10 physiographic provinces, 5 of 18 river basins, and 4 of 8 aquatic ecoregions could
serve as fish faunal regions in Oregon (Figure 4). This indicated that, statewide, ecoregions offer the
single most suitable system to classify fish assemblages, but that they alone are insufficient,
Rohm et al, (1987) and Matthews and Robison (1988) analyzed the fish fauna of Arkansas through
use of an ecoregion and a data base/drainage units approach, respectively. Rohm et al. used collections
from 22 streams in the 6 ecoregions of Omernik, whereas Matthews and Robison described 5
discontinuous fish faunal regions from over 2000 collections, but mapped the regions as individual
drainage units. In order to make comparisons at a similar scale for this paper, their 101 drainages were
coded and plotted by the 5 major river basins and 6 ecoregions of Arkansas (Figure 5). Both Rohm et
al. and Matthews and Robison distinguished two lowland regions and an Ozark region. However,
Matthews and Robison's Ouachita-Ozark border region included Omernik's Ouachita and Boston
Mountains regions, and part of his Ozark region. Matthews and Robison did not delineate a separate
Arkansas River Valley region. The actual ordinations in both papers showed considerable differences
between lowland and Ozark regions, but a gradual transition among the other regions.
These examples illustrate two inadequacies with river basins and Omernik's ecoregions as
frameworks for fish monitoring. (1) Pflieger and Matthews and Robison described a large river fauna that
ecoregions and basins may miss. (2) Available fish data offer more detailed information about fish
presence and absence than ecoregions, and, consequently, should be examined while developing
regional expectations for fish assemblages.
On the other hand, a focus on available data (fish or other assemblages) presents different
problems. Single assemblage analyses are appropriate only for that assemblage or data base. It is
unrealistic to expect state and federal agencies to develop individual regions for algae, benthos, fish, water
quality, and physical habitat. Agencies must manage lakes and streams as aquatic ecosystems. It is
theoretically possible to simultaneously ordinate a number of assemblages and physical and chemical
habitat variables, but to our knowledge this has not been demonstrated.
Regardless of whether available water body data are used to draw ecological regions or whether
Omernik's ecoregion map is used, there is a need for a hierarchical set of regions. Many state and federal
monitoring agencies lack the resources to monitor and interpret data at a site-specific level, except at a
small number of sites. Consequently, agencies tend to make screening assessments at a regional level.
Regions at the scale of Omernik's ecoregions or Pflieger*s fish faunal regions are appropriate for such
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purposes. Scientists concerned with cause and effect and compliance monitoring require less
heterogeneous regions, perhaps at the habitat type scale. We are a long way from delineating such
classifications at the state or national level. Intermediate regions at the scale of drainage units (Matthews
and Robison 1988) or subregions (Clarke et al. 1991, Gallant et. al. 1989) offer greater precision than
regions at far less expense than habitat classification, but their usefulness is untested.
The research described above also reveals the wisdom of considering both drainages and
landscape characteristics when delineating regions, regardless of scale. Clearly, the distributions of fishes
and nonflying macroinvertebrates are restricted to historical and present water bodies. Additionally, it is
clear that considerable heterogeneity exists within drainages. For example, Hughes and Gammon (1987)
found distinctly different fish assemblages in four reaches of the mainstem Willamette River, Oregon.
Omernik and Griffith (1991) were better able to stratify the heterogeneity of dissolved oxygen in Arkansas
streams and the fish assemblages in the Calapooia River, Oregon, through the use of ecoregions than
through drainages (Figure 6). Hawkes et al. (1986) indicated a substantial difference in Walnut Creek,
Kansas, which is divided into two ecoregions (Figure 1). Finally, Smith et al. (1981) observed that fishes
of the Raisin River, Michigan, were distributed in a nonrandom pattern; distributions of some species
change near ecoregion boundaries (Figure 7).
Despite being classified by drainage unit, the results of Matthews and Robison reveal that
ecoregions may better classify fish regions than do river basins, at least among lowlands. All the big
rivers of Arkansas share a similar fauna. Within basins, there are regional differences as one moves
across ecoregions; however, there are no obvious basin differences within ecoregions. Although neither
basins nor ecoregions classified fish assemblages accurately, ecoregions were consistently more accurate
than basins (Figure 5, Table 1). It seems wise, then, to consider both ecoregions and drainage units in
delineating fish faunal regions, regardless of the scale of interest.
MANAGEMENT APPLICATIONS OF ECOREGIONS
Although ecoregions and some other forms of water body classification are useful to researchers
interested in large scale patterns, their greatest proponents are agency scientists charged with monitoring
and assessing many waters across a large area. Two states, Minnesota and Ohio, have made extensive
use of ecoregions, as well as of existing data.
In Minnesota, Moyle (1956) recognized regional patterns in lake productivity as a result of
differences in geology, hydrology, vegetation, and land use. More recently, the Minnesota Pollution
Control Agency (MPCA) has used Omernik's map to assess patterns in lake trophic state and
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morphometry and apply the results to lake management. Heiskary and his colleagues (Heiskary et al.
1987, Heiskary 1989, Heiskary and Wilson 1989) used trophic state variables from a 1400-lake MPCA data
base, existing fish data, and a data base from 90 minimally disturbed reference lakes to evaluate four lake-
rich ecoregions. Marked ecoregional differences occurred for total phosphorus (Figure 8) and fish
assemblages (Table 2). Heiskary and Wilson also found ecoregional differences in user perceptions about
conditions suitable for swimming and for what constitutes a nuisance algal bloom. Persons in regions
where lakes are typically clearer required lakes to be twice as clear as did people in regions characterized
by more turbid lakes (Figure 9). Information such as this has been very useful for a staff of 2 to 3
limnologists in planning, goal setting, and communicating with citizens about the 12,000 lakes in the state.
Ecoregions facilitated quantitative regional estimates of reasonable trophic state values and variability, and
improved model predictions of trophic state variables and data interpretation among neighboring states.
Ohio, like Minnesota, was graced by early regional analyses conducted by an ichthyologist.
Trautman (1957) found physiographic regions useful frameworks for fish faunas and he reviewed
Omernik's draft Ohio ecoregion map. The Ohio Environmental Protection Agency (OEPA) used Omernik's
ecoregions and a fish and macroinvertebrate data base from over 300 minimally disturbed reference sites
to develop biological criteria for the 45,000 miles of streams and rivers in Ohio (OEPA 1987, 1988,
1989a,b, Yoder 1989). The reference site data base was used to calibrate the index of well-being
(Gammon et al. 1981), index of biotic integrity (Karr 1981, Karr etal. 1986), and an invertebrate community
index (OEPA 1987). Index values determined from the regional reference sites were used to set regional
criteria for ambient biological assemblages. Values for each index were plotted by ecoregion and
warmwater criteria were set at the 25th percentile for streams of three size ranges (headwater, wading,
boat) in each region (Yoder 1989, Figure 10). Criteria for exceptional and physically modified sites were
also developed. The ecoregional reference sites are systematically remonitored to adjust calibration
curves and biological criteria and to evaluate background changes in biological integrity. Biological
criteria are used by OEPA to demonstrate temporal and spatial trends (Yoder 1989, Figure 11), detect
impairment of aquatic life uses (Yoder 1991), provide biennial water resource summaries (OEPA 1990),
and diagnose types of stressors. Quantitative biocriteria are not only a major improvement over chemical
criteria, they also provide a more accurate measure of water resource quality than the more commonly
used narrative criteria. In a study of over 400 sites, OEPA found 61% of the sites attaining and 9% not
attaining narrative biological criteria based on professional judgement. When numerical biological criteria
based on macroinvertebrate assemblage scores at regional reference sites were applied to the same sites,
34% attained and 44% did not attain the criteria (Yoder 1991).
Use of regional reference lakes or stream reaches (Hughes et al. 1986) to develop water resource
criteria is hindered by ecoregion heterogeneity. Regional reference sites are inappropriate benchmarks
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for sites that naturally differ from them, to a considerable degree. For example, sites with substantial
natural difference in gradient, substrate, or water quality in the same ecoregion should not have the same
set of reference sites. If such sites occur in a distinct geographic pattern, the ecoregion should be
subregionalized (Gallant et al. 1989). If there is no pattern to the differences, reference sites for each type
of natural gradient, substrate, or water quality should be selected.
Reference sites in extensively disturbed regions may be extremely difficult to locate and may
represent unacceptable levels of degradation. But use of least degraded or desirable sites in such areas
offers a realistic goal for improvement. Lake sediment cores may offer alternative references for
assemblages preserved therein (Charles et al. this volume); however, criteria based on presettlement
conditions are unrealistic without major changes in land use. Minimally disturbed catchments or sites can
serve as references of the best we can expect, given current land use patterns, and they are certainly in
better than average condition. Reference site selection involves both objective and subjective standards
(Table 3) and many sites are necessary where regions are heterogeneous or where numerous water body
types occur in a region. Many of these issues will require additional federal and multi-state research and
analysis to resolve.
CONCERNS ABOUT THE USE OF ECOREGIONS
Is ecosystem health a value concept and consequently not determinable scientifically? Ecosystem
health certainly involves values; however, Karr (this volume) and Karrand Dudley (1981) offered a solution.
They defined ecosystem health, or biological integrity as "a balanced, integrated, adaptive community of
organisms having a species composition, diversity, and functional organization comparable to that of
natural habitat of the region." Ecoregions offer a regional framework for classifying natural habitat and
for stratifying entire communities, as opposed to an individual assemblage such as fish or
macroinvertebrates. Ecoregional reference sites represent comparable natural habitat against which the
integrity of other sites in the ecoregion can be compared. Moyle (this volume) emphasized that there is
not one healthy community, but several. The set of ecoregional reference sites used by Ohio EPA and
Minnesota PCA provide examples of such communities. Contrary to the implications of Conquest et al.
(this volume), we should not require only pristine systems as references. Doing so usually restricts us to
no benchmarks for evaluating restoration results or deterioration. Also, many of our most pristine arctic
and mountain waters are impacted by atmospheric deposition. Even if they were not, they would be
inappropriate references for waters in other regions. Regional reference sites would certainly offer Stewart
and Loar (this volume) and others benchmarks for evaluating assemblages in streams with highly
perturbed headwaters. Of course, such sites must be monitored regularly to evaluate the degree to which
they change as a result of natural and anthropogenic modifications.
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Is any geographic framework ready for immediate adoption by state and federal management
agencies? Additional tests of ecoregions, basins, and other frameworks are needed in areas other than
those already studied. Such tests should involve multiple variables to examine ecosystem or community,
as well as assemblage, differences, and similarities, because we cannot afford to develop many issue- or
variable-specific regions for large areas. Even if we could develop many variable-specific regional maps,
state and federal management agencies would find them difficult to use. The research would be even
more useful if done at more than one scale. Existing lake chemistry and fish and macroinvertebrate data
bases are promising sources of information for such analyses, particularly the fish data bases residing in
many museurns.
Can we base ecoregions on geology or individual chemical, hydrological. and topographic
variables? Omernik's ecoregion map actually integrates these variables by using maps of landform, soil,
and vegetation, in addition to other mapped information. These maps, in turn, were drawn from
considerable site specific chemical and physical data.
Do the 76 ecoregions of the U.S. incorporate too much heterogeneity? The answer to this
question depends on their use. They are too detailed for some uses and users and not detailed enough
for others. This is why a hierarchical set of regions would be appropriate. Omemik is now working with
individual states, focusing on ecoregions that are particularly troublesome or important to managers. The
Science Advisory Board of the U.S. Environmental Protection Agency (1991) recommended that the
Agency fund subregionalization, along with further tests of ecoregions, but this has not occurred.
Must we deal with individual lakes or stream reaches? If our research is limited only to the system
that we study, that leaves an enormous number of unstudied systems about which we are ignorant. It is
very useful to study individual water bodies and be able to extrapolate the results to others. Ecoregions
provide a useful framework for bounding our extrapolations. It is unwise to assume that structures and
functions characteristic of a small northern mountain lake or stream typify all lakes and streams, or even
all mountain waters. Water resource managers do not have the luxury of such research. Whether they
take action or accept the status quo, they must extrapolate their knowledge of a relatively small proportion
of waters. If we ever hope to understand and manage all lakes or streams, we must begin to assess and
regulate them as populations, as well as individuals. Then we can use population-based information to
help us make decisions about individual water bodies. Ecoregions simply are a way to classify
landscapes and their watersheds so that we can generalize, much in the same manner that we use
taxonomic classifications to generalize in biology.
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Might we be just as well, or better, off with a coarse classification of vegetation (say agriculture,
grassland, deciduous forest, and coniferous forest) it we are interested in process or function rather than
composition? This is an interesting point because most of our examples involve species composition.
Minshall et at. (1985) stated that climate, geology, and land use may explain a great deal of the process
differences found across the northern U.S. However, ecoregions can be easily aggregated by color on
Omernik's map, which will offer a biome level classification, and the map of Omernik and Gallant (1990)
is at the biome scale of resolution. Note also that many ecoregions, such as those in Minnesota,
subsume these major vegetation breaks and provide a useful framework for stratifying lake processes.
As we learn more about stream processes and monitoring data become more available from more places,
we may want greater detail than that provided by biomes. Presumably, we will also continue to be
interested in species and guilds, for which greater regional detail is useful.
Can we use river basins as the classification tool as is done in Britain? We do use basins in this
way in the U.S., but they are problematic. Basins frequently cross ecoregions that are drastically different
(mountains, plains). Therefore, river basins and hydrologic units frequently do not correspond with
patterns in aquatic variables, as this paper, Omernik and Griffith (1991), Hughes and Gammon (1987), and
Smith et al. (1981) demonstrate. It is appropriate to evaluate both basins and ecoregions, especially for
fishes.
Is it possible to regionalize by stressor (such as acid rain) and lake or watershed size? This is
an effective approach where there is a single very important issue. Omernik and his colleagues developed
alkalinity maps (Omernik and Griffith 1986, Omernik and Powers 1983) that were used to frame regions
of sensitivity to acidification for EPA's National Surface Water Survey and produced nutrient maps for
evaluating patterns in eutrophication (Omernik 1977, Omernik et al. 1988). However, where agencies are
concerned with multiple problems and multiple indicators, a general ecoregion map is more appropriate.
The map need not and cannot be optimal for all purposes and users; it should be adequate, useful,
logical, and able to explain much of the observed variance.
When will the mapping of ecoregions be complete? It is important to realize that there are two
national ecoregion maps developed by EPA to date (Omernik 1987, Omernik and Gallant 1990). Work
is continuing at the subregion scale through cooperative work with a handful of states, but it receives no
research funds from EPA at present. The entire ecoregion project has been an evolving process
leapfrogging among monitoring, research, and regulation. The lack of a national ecoregion research and
mapping program to assist states in developing biological criteria means that some states will be
inadequately mapped and that inconsistent maps may be produced by the states.
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What are the dangers of using ecoregions blindly? As with any new idea, especially one that has -
an entire country as its subject, it is likely that ecoregions will be misused. They are presently being
applied to develop biocriteria. We would be concerned if states ignore basin differences where they exist,
overlook subregion differences where they are great,-disregard different stream or lake types and sizes
in the same region, assess too few reference sites to obtain a meaningful estimate of variability, or use
ecoregions where they are obviously inadequate or for purposes for which they were not intended. On
the other hand, we would be concerned if academic researchers fail to use ecoregions to bound their lake
or stream study areas or to examine regional patterns in other lakes or streams of that type.
Given the resource shortages of state agencies and university researchers, why not involve more
academies in ecological monitoring? This is something that Societas Internationalis Limnologiae and other
professional associations focusing on water issues could try to foster. It would be possible only for
academics that have the time to conduct considerable monitoring for months at a time and through the
use of standard, quality controlled methods. Agencies need funding mechanisms that allow easy transfer
of research funds, as opposed to hiring staff. Both parties would require equal access to the data and
it should be in easily accessible data bases, along with historical data. As the Environmental Monitoring
and Assessment Program (EMAP, Paulsen, this volume) is implemented, there is likely to be considerable
demand for academic biologists to conduct much of the field work and taxonomic identifications. EMAP
and ecoregion researchers must also continue to seek and evaluate existing data bases and consult with
state and local experts.
CONCLUSIONS
Study and management of anything as complex as lake and stream ecosystems requires
recognition of local, regional, and historical factors or filters (Ricklefs 1987, Tonn 1990). An ecoregion
focus can be damaging if we ignore the local scale, but more frequently we tend to focus on the local
factors and fail to see the broader picture.
We can also be misled by available museum data. Although greater use of such data is
warranted, that use must be tempered by knowledge of how thoroughly the data were collected at the site,
the quality of the proportionate abundance estimates, and the spatial intensity of the collections, both
regionally and by water body type and size. Nonetheless, museum data, especially if compiled nationally
or across a multi-state region, could be valuable for estimating species pools, for calibrating indices such
as the index of biotic integrity (Karr 1981, Karr et al. 1986), and for determining locations where sub-
ecoregions require delineating.
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Fish faunal regions generated from museum data, together with ecoregions, should facilitate
federal and interstate cooperation in biological monitoring by providing common biogeographic
frameworks. Of course, this will still require much more federal leadership than currently exists to avoid
generating inadequate, redundant, and conflicting state and federal biological monitoring programs.
We should be encouraged by renewed interest in biological monitoring and criteria evidenced by
this workshop and others (McKenzie In Press, USEPA 1987, Yount and Niemi 1990), by the EPA's
requirement for states to develop biological criteria (USEPA 1990), by large national biological monitoring
programs (Gurtz this volume, Paulsen this volume), and by the growing number of states that are
increasing their biological monitoring. However, much remains to be done, A very small part of state and
federal budgets are spent on monitoring the biological resources that citizens assume we are protecting
and little of that monitoring information is used in making management decisions. This is particularly
discouraging as the resources we love and study disappear to human overpopulation and
overconsumption before we even get to know them very well (Hughes and Noss 1992).
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ACKNOWLEDGMENTS
This paper was, in part, derived from a panel discussion held at a workshop, Biological Monitoring of.
Freshwater Ecosystems, held at Purdue University, West Lafayette, Indiana, December 1990. We thank
Stan Loeb for inviting us to participate and the Environmental Monitoring and Assessment Program-
Surface Waters Group of the U.S. EPA for travel expenses. An earlier draft of this manuscript was
improved through reviews by Susan Christie, Deborah Coffey, John Giese, Phil Larsen, Stan Loeb, Terry
Maret, Jim Omernik, and Bill Platts. The research was partially funded by the U.S. Environmental
Protection Agency through contract 68-C8-0006 to ManTech Environmental Technology, Incorporated.
This chapter was partially prepared at the EPA Environmental Research Laboratory in Corvallis, Oregon,
and subjected to Agency peer and administrative review and approved for publication.
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Canadian Journal of Fisheries and Aquatic Sciences 41:1781-1802.
Lyons, J. 1989. Correspondence between the distribution offish assemblages in Wisconsin streams and
Omernik's ecoregions. American Midland Naturalist 122:163-182.
Matthews, W.J. and H.W. Robison. 1988. The distribution of the fishes of Arkansas: a multivariate analysis.
Copeia 1988:358-374.
McKenzie, D. (ed) In Press. Ecological indicators. Elsevier. Essex. England
Minshall, G.W., K.W. Cummins, R.C. Petersen, C.E. Cushing, D.A. Bruns, J.R. Sedell, and R.L. Vannote.
1985. Developments in stream ecosystem theory. Canadian Journal of Fisheries and Aquatic Sciences
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Moyle, J.B. 1956. Relationships between the chemistry of Minnesota surface waters and wildlife
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13
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Moyle, P.B. This Volume.
OEPA. 1987. Biological criteria for the protection of aquatic life: Vol II: user's manual for biological field
assessment of Ohio surface waters. Ohio Environmental Protection Agency. Columbus, OH.
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Environmental Protection Agency. Columbus, OH. — •
. 1990. Ohio water resource inventory. Ohio Environmental Protection Agency. Columbus, OH.
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If
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Omernik, J.M., D.P. Larsen, C.M. Rohm, and S.E. Clarke. 1988. Summer total phosphorus in lakes: a map
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U.S. Environmental Protection Agency. 1987. Report of the national workshop on instream biological
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Washington, DC. -
Yount, D.J. and G.J. Niemi (eds). 1990. Recovery of lotic communities and ecosystems following
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Table 1. Percent misclassifications* of Arkansas fish faunal regions by ecoregion and river basin.
% Misclassifications
Faunal Region Ecoregion River Basin
1 34 64
2 61 74
3 67 71
4 46 83
*Misclassification is defined as a fish assemblage other than that predominating in that ecoregion or basin.
17
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Table 2. Ecological classification of all lakes greater than 60 hectares (approximately 1800 lakes) within
4 Minnesota ecoregions (from Borchert et al. 1970 and Heiskary et al. 1987).
Lake Class
Lake trout
Walleye
Bass-panfish-walleye
Builhead-panfish
Winterkill-roughfish
No data/other
NLF
2
20
48
4
13
13
CHF
37
6
34
18
Ecoreqion (%)
WCP
13
14
65
8
NGP
7
4
66
23
NLF (northern lakes and forests), CHF (central hardwoods forest), WCP (western cornbelt plains), NGP
(northern great plains).
IS
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Table 3. Steps in ecoregional reference site selection.
1. Define area(s) of interest on maps
Delineate ecoregions and subregions on 1:250,000 scale maps
Delineate river basins and subbasins supporting different faunas
Combine regions and basins to produce potential natural regions
2. Define water body types, sizes, and classes of interest
Evaluate their number and importance in the region
3. Delineate candidate reference watersheds through use of maps, available data, air photos, and local
experts
Eliminate disturbed areas
Point sources (atmospheric, aquatic)
Hazardous waste sites, landfills
Mines, oil fields
Feedlots, poultry farms, hatcheries
Urban, industrial, commercial, residential
Channelization, dams
Transportation and utility corridors
Logged or burned forests
Intensively grazed or cropped lands
Seek minimally disturbed, typical areas or potential natural landscapes
Agricultural or range oases
Old growth forests, woodlots
Roadless areas
Preserves, refuges, exclosures
4. Conduct field reconnaissance to locate potential natural sites
Aerial observation, remote sensing
Site inspection
Extensive, old riparian vegetation
Complex channel morphology
Variable substrate, with large resistant objects and minimal sedimentation
Considerable cover (overhanging vegetation, undercut banks, large woody debris, deep pools,
large turbulent riffles, macrophytes)
n
-------
High v.'ater quality (clear, odorless)
_ Vertebrates and macroinvertebrates present
Minimal evidence of humans, livestock, and human activity
5. Determine number of ecoregional reference sites needed
Balance regional variability, resources, and study duration
6. Monitor sites and evaluate their chemical, physical, and biological integrity. At least two assemblages
should be evaluated.
SLC
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UST OF FIGURES
Figure 1. Comparison of Pflieger et al. (1981) fish faunal regions (dotted lines) and Omernik's (1987)
ecoregions (solid lines) in Missouri.
Figure 2. Comparison of Hawkes et al. (1986) fish faunal regions (dotted lines) and Omernik's (1987)
ecoregions (solid lines) of Kansas.
Figure 3. Fish faunal regions (dotted lines) of Bazata (1991) and ecoregions (solid lines) of Omernik (1987)
for Nebraska.
Figure 4. Fish assemblages relative to the 8 aquatic ecoregions (solid lines, letters) and 19 river basins
(dotted lines, circled numbers) of Oregon (from Hughes et al. 1987). Uncircled numbers are from a cluster
analysis. ...
Figure 5. Fish assemblages relative to the six aquatic ecoregions (solid lines, letters) and five river basins
(dotted lines, circled numbers) of Arkansas (from Matthews and Robison 1988). Uncircled numbers are
from a detrended correspondence analysis.
Figure 6. Fish assemblages of the Calapooia River, Oregon, relative to aquatic ecoregions (from Omernik
and Griffith 1991). Letters are from a reciprocal averaging ordination.
Figure 7. Three fish species distributions relative to ecoregions in the Raisin River basin, Michigan (from
Smith etal. 1981). Southern Michigan/northern Indiana till plains (SMNI), eastern corn belt plains (ECBP),
Huron/Erie lake plain (HELP).
Figure 8. Box plots of total phosphorus concentrations by ecoregion-northem lakes and forests (NLF),
central hardwoods forest (CHF), western cornbelt plains (WCP), northern great plains (NGP) (from
Heiskary et al. 1987). Box width reflects number of lakes, CI is 95% confidence interval of the median;
open circle is the reference lake median (from Heiskary 1989).
Figure 9. User perceptions of (a) recreational suitability (no swimming) and (b) physical appearance
classes (high or severe algae). Ecoregions as in Figure 8 (from Heiskary and Wilson 1989).
-------
Figure 10. Box plots of Ohio reference sites for wading streams by ecoregion-Huron Erie lake plain
(HELP), interior plateau (IP), Erie Ontario lake plain (EOLP), western Allegheny plateau (WAP), eastern
corn belt plain (ECBP) (from Yoder 1989). Box notch represents 95% confidence interval of the median;
the number above the acronym is the number of reference sites per region.
Figure 11. Longitudinal trend in the index of biotic integrity (IBI) between 1979 and 1987 for the Scioto
River near Columbus, Ohio. Flow is from left to right, vertical arrows indicate major pollution sources, IBI
of 40 equals biological criterion for warmwater habitat, 50 is the criterion for exceptional warmwater habitat
(from Yoder 1989).
<22
-------
f: ><
-------
I
N
F i ^ f
at
-------
50
•>»
U> '
(S
-i
!
-------
100
BO
OREGON
Willamette
Vol ley
Willamefre
Volley Plains
Plains
40
20
Foothills
20 40 60 80 100
Western
Cascades
FISH ASSEMBLAGES
6 Willamette Volley Ploins
B Willamette Volley Foothills
C Brush Creek
D Western Cascades
E Western Cascades Headwaters
AC
-------
O lowo Dorter
• Mottled Sculpin
a Silverjow Minnow
MICHIGAN
HELP
f/3?
Legend
Percentile A 454
A 449
(ftg/L)
NLF CHF WCP NGP
Ecoregion
<37
JET* * SP
3
-------
c NLF
-0) 1 ® - i
o
- - ¦
CP
0
T
1
CHF
o
o
^ WCP
- \ 1
i l i l i 1 i 1 i 1 i
0 04 0.8 1.2 1.6 2.0 2.4
Secchi Depth (m)
c NLF
o
CP
^ CHF
o
o
U WCP
b)
f- ' 0 - 1
-
I
© 1
Percentile
isk®^em
0
1
j
i i
25 50 75
1 , 1 i 1
0 0.4 0.8 1.2 1.6 2.0
Secchi Depth (m)
2.4
IBI
60
50
40
30
20
10
0
I Percentile
t J75
>-
-------
CSO WWTP WWTP
EWH
„ * WWH
W/////?//////////W
1979
Min IBI -12
CSO WWTP WWTP
WWH
_ 1987
MinIBI=12
Flow
_i i i_
_L
135 130 125 120 115 110 105 100
River Mile
F,
A"?
-------
ERL-COR- /"/-7SJD
TECHNICAL REPORT DATA
(Hcste ma Imttructiom on tht rtvtnr befarr compter
N
i. report no.
EPA/600/A-92/204
a.
PBy -
-10 6/JO
J
4, TITLE *NO SUIT IT Li
Use of Ecoregions in Biological
S. REPORT DATI
Monitoring
S. PiRPORMINO ORGANIZATION COSE
7. AUTHORISI
R.M. Hughes, S. A. Heiskary,
W.J. Matthews, C.O. Yoder
S. PERFORMING ORGANIZATION REPORT NO.
». PERFORMINQ OROANIZATION NAME AND ADDRESS
METI, Corvallis, OR
10. PROQRAM ELEMENT NO. —
MN Poiiu. contr. Agy. , bt. Paul, mm
U. of 0, Kingston, OK
Ohio EPA, Columbus, OH
% I. C6^TAaCT/CHanT k6.
12. SPONSORING AGENCY NAME AND ADDRESS
US Environmental Protection Agency
Environmental Research Laboratory
200 SW 35th Street
Corvallis, OR 97333
13. TYPE OF REPORT AND PERIOD COVERED
Symposium Paper
14, SPONSORING AGENCY CODE
EPA/600/02
IS, SUPPLEMENTARY NOTES
1991. In: Symposium on: Biological Monitoring of Freshwater
Ecosystems, Purdue Univ., West Lafayette, IN Nov. 29 - Dec. 1, 1990
IS. ABSTRACT
^.In order to better manage populations of lakes and streams it is useful
to have some form of lake and stream classification. In biological
monitoring programs, an appropriate geographic framework is useful for
developing estimates of organisms likely to be collected and conditions
likely to be encountered. As assemblage and water quality data bases
and statistical software have become available, they have been used to
frame regions. Others have compared aquatic ecosystem patterns with
various environmental variables. The purpose of thi-s' paper is to
compare fish faunal regions and ecoregions, summarize the-experience of
two states that use ecoregions as management units, and summarize the
concerns of workshop participants about the use of ecoregions• ?»
KB* WORDS AND DOCUMENT ANALYSIS
i. descriptors
b. IDENTIFIERS/OPEN iNDED TERMS
c. COSATi FieW/Gtoup
Ecoregions, river basins,
fish faunal regions, biomonitoring,
biocriteria
t«. DISTRIBUTION STATEMENT
IS. SiCfJRIT*Cj,ASS (Thu Htport)
Unclassified
3i.NO. Of PASES
30
Release to Public
70 SECURITY CLASS (ThUftgtJ
Unclassified
aa. price
CPA Fum U>M (t-fS)
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