S.O.L.E.O.
1994 State of the Lakes Ecosystem
Conference
Background Paper
Aquatic Habitat and Wetlands
of the Great Lakes
August 1995
Environment Canada
United States Environmental Protection Agency
EPA 905-R-95-014
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State of the Great Lakes Ecosystem Conference
Background Paper
AQUATIC HABITAT AND
WETLANDS
OF THE GREAT LAKES
Doug Dodge
Ontario Ministry of Natural Resources
Maple, Ontario
Robert Kavetsky
U.S. Fish and Wildlife Service
East Lansing, Michigan
August 1995
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CONTENTS
EXECUTIVE SUMMARY v
1.0 Introduction , 1
2.0 Habitat Types in the Great Lakes 3
2.1 Open-Lake , 3
2.2 Coastal Wetlands 4
2.3 Shoreline 6
2.4 Tributaries . 7
2.5 Connecting Channels 7
2.6 Inland Habitats 8
3,0 Ecological Significance of Habitat Types 9
3.1 What's Important: Indicators of Significance 9
3.1.1 Role in nutrient cycling 9
3.1.2 Productivity 10
3.1.3 Influence on water quality and quantity 13
3.1.4 Essential Habitats 14
3.1.5 Biodiversity 15
3.1.6 Indicator species 17
3.2 The Unique Role of Coastal Shore/Coastal Wetlands 17
4.0 State of the Habitats 19
4.1 Overall Quantity and Quality by Habitat Type 19
4.2 Lake Superior 25
4.3 Lake Michigan 26
4.4 Lake Huron 27
4.5 Lake Erie 28
4.6 Lake Ontario 30
4.7 Connecting Channels 32
5.0 Types of Impact on Habitat 37
5.1 Chemical Changes 37
5.2 Hydrological Changes 39
5.3 Physical Process Changes 41
5.4 Physical Alteration 42
5.5 Changes to Community Structure 43
5.6 Impact Analysis 44
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6.0 Existing Initiatives 45
6.1 Research and Information Gathering 45
6.2 Habitat Protection 46
6.3 Restoration 49
6.4 Authorities 51
7.0 Management Implications 57
8.0 References 61
8.1 Other Sources Used 65
8.2 Acknowledgements 66
9.0 Postconference Addendum 67
NOTICE TO READER
These Background Papers are intended to provide a concise overview of the status of
conditions in the Great Lakes, The information they present has been selected as
representative of the much greater volume of data. They therefore do not present all research
or monitoring information available. The Papers were prepared with input from many
individuals representing diverse sectors of society.
The Background Papers were first released as Working Papers to provide the basis for
discussions at the first State of the Lakes Ecosystem Conference (SOLEC) in October, 1994,
Information provided by SOLEC discussants was incorporated into the these final SOLEC
background papers. SOLEC was intended to provide key information required by managers
to make better environmental decisions.
IV
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EXECUTIVE SUMMARY
Aquatic habitat loss and degradation is insufficiently documented. Data that would shed light
on the larger picture and its repercussions are almost non-existent. Instead, there are numerous
local studies, split by watersheds, jurisdictions and disciplines. The assessment of the state of
the habitats remains almost entirely anecdotal. However, the sheer number of anecdotes and their
basic agreement allow only one conclusion: that habitat loss and degradation in the Great Lakes
basin have been very high, especially in the highly productive and diverse inshore zone and the
connecting channels.
By and large, the open Lakes are recovering from the eutrophication of the last decades.
However, many species associated with them remain threatened because the inshore, shoreline
and tributary habitats which they also require have been lost or impaired. The dependence of the
lakes and the species that are associated with them on healthy shoreline, inland and tributary
habitats has been largely neglected. As a result, the impoverishment of these habitats has hardly
registered as a Great Lakes issue.
Most habitat losses to physical changes (e.g. filling, bulkheading, etc.) are likely irreversible,
while losses caused by biological and chemical changes have the potential to be reversed.
Accordingly, it makes sense to focus on stopping the ongoing pattern of loss and impairment.
Present losses are rarely the large-scale conversion of habitat to other uses; degradation is more
common, in a variety of subtle guises that truly require an ecosystem approach to understand and
reverse.
In recognition of the interrelated nature of living systems and their habitats, there is a growing
realization of the need not only to protect the species that are in imminent danger of extinction,
but to consider the entire picture and anticipate threats of extinction long before they become
acute. To do this it is necessary to consider entire ecosystems, not just artificially separated
fragments of them. Consideration of habitat is an essential component of this approach.
Clearly the health of habitat and wetlands is a major concern in the Great Lakes Basin. A
number of programs, laws and policies already exist to enhance habitats in the Great Lakes
Basin. What is needed to better protect and restore wetlands and other aquatic habitats is
probably not more laws, but rather stronger will to conserve habitats, and implementation and
enforcement of existing laws, regulations and policies. Coupled with this need for improved
implementation and policy is the need for a strategic approach to habitat protection and
restoration, making full use of all levels of partnerships.
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1.0 Introduction
Concern about habitat and especially wetland loss in the Great Lakes Basin has grown in recent
years. Protecting and restoring Great Lakes habitats requires an understanding of the importance
of healthy habitat in sustaining human and all other life. This understanding is necessary both
at the level of the whole basin, and for the individual habitats within the basin. If the habitats
of the Great Lakes are like a great life-supporting net, we need to know where the holes and
weak spots are so that we may give them our attention first. Because the Lakes are part of such
a vast ecosystem, and action to protect, preserve and restore it is needed in so many areas, it is
critical to take bearings, and to understand the linkages in order to inform and guide this work.
For the purposes of this paper habitat means that space that is or can be successfully occupied
(inhabited) by a species or biotic community or some broader (taxonomic or phylogenetic) entity.
Habitat is simply the place where an organism or group of closely related organisms live. The
goal of habitat preservation can only be described in terms of those biotic entities. This paper
provides the basis for discussion of the habitat values of the Great Lakes by addressing the
following questions:
1. What habitat types are there and how are they linked?
2. By what criteria can the significance of a habitat be judged?
3. How significant are each of the habitat types?
4. Which habitats are most threatened by which human actions?
5. How adequate are current efforts to preserve and restore habitat?
6. Where do current actions and future initiatives need to focus in order to ensure a healthy
web of habitats capable of supporting a diversity of life of the basin?
The answers to these questions remain incomplete.
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2.0 Habitat Types in the Great Lakes
For the purposes of this paper, habitats of the Great Lakes have been divided into the following
types:
Open-lake
Coastal wetlands
Shoreline
Tributaries
Connecting channels
Inland habitats
Numerous classification systems exist, and their diversity speaks to the fundamental problem that
plagues such systems - habitats that belong together are often classified separately and others,
quite distinct, are clustered together. The scheme chosen for this paper is a hybrid of other
systems based on spatial distinctions. The reality of gradients and close linkages should not be
confused with the usefulness of a model as a basis for organizing discussion.
The habitat classification used here differs from the distinctions recently proposed by the Nature
Conservancy (1994), and highlights the differences between tributaries and connecting channels,
and includes inshore areas other than wetlands. The number of inland and shoreline habitat
categories has been reduced to allow a greater focus on the lakes themselves.
Other classification systems have been created for a variety of purposes: a brief discussion of the
opportunities and obstacles created by numerous systems is found in Section 6.1 below.
Each of these broad habitat categories includes a range of habitat types. In general, the natural
distribution of habitat types within the Great Lakes depends on lake bed and shore topography,
geology and climate.
2.1 Open-Lake
The open lake includes both the inshore and offshore waters of the lakes. The inshore waters
begin at the offshore edge of the coastal wetlands and extend lakeward to the point where vertical
thermal stratification can be measured in summer. This point, where the thermocline intersects
with the lake bed, is usually taken as the boundary between the inshore and offshore waters.
This boundary is dynamic and moves progressively farther offshore and into deeper water as the
summer progresses. Minor differences in water depth and distance from shore at the boundary
location can occur between lakes and in response to local hydrologic conditions within each lake
and at any point in time. At the end of summer the thermocline may be as deep as 30 meters
in Lake Michigan.
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Fish are the dominant fauna of the open lake. During the summer, coldwater fishes including
trout, salmon, and whitefish occupy the deeper, colder offshore waters, while cool- and
warmwater fishes inhabit the shallower, warmer, inshore waters, Phytoplankton occupy the upper
layers of the open lake and benthic algae colonize the shallower portions of the lake bed where
sunlight is sufficient to support photosynthesis. Light penetration may extend only a meter or
less in some areas and to more than 60 meters in others. Zooplankton colonize the open lake
from the surface of the water to the lake bed, and productive and diverse benthic invertebrate
communities occupy the lake bed wherever it has not been degraded.
Most inputs of energy, nutrients, and pollutants to the open lake are made directly to the inshore
waters. These additions may cycle in the inshore waters, but eventually most find their way into
the offshore waters, where they may be cycled less frequently or simply stored in bottom deposits
in deep water. Smaller amounts of these energy and materials resources, when incorporated into
fish, find their way back into coastal wetland, tributary, connecting channel, and terrestrial
habitats as fish migrate inshore to spawn or as avian predators and humans ingest fish from the
open lake.
2.2 Coastal Wetlands
In shallower water, a range of phenomena occur that are not possible in deeper water. Sunlight
penetrating to the bottom makes possible the growth of rooted plants; and wave and wind energy
are transformed by the lake bottom and shore, depositing sediments and causing erosion.
Tributary flows change chemical and sediment concentrations and temperatures. The critical
parameters determining the type of habitat are water depth, seasonal and long-term water level
fluctuation, degree of exposure to wind and waves, substrate, and chemical and temperature
regime. As a result of limited mixing and the variability of critical parameters, strong gradients
exist over relatively short distances.
The boundary separating inshore from open-lake habitats lies where light ceases to penetrate
significantly to the lake bottom. The depth at which this level of light extinction occurs varies
tremendously between and within the lakes, but is usually less than 10 meters.
Of great interest within the inshore zone are wetlands, defined by the U.S. Fish and Wildlife
Service (Cowardin et al, 1979) as:
"...lands transitional between terrestrial and aquatic systems where the water table is
usually at or near the surface or the land is covered by shallow water. For the purposes
of this classification, wetlands must have one or more of the following attributes: (1) at
least periodically, the land supports [aquatic plants]; (2) the substrate is predominately
undrained hydric soil; or (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."
An alternative definition has been developed by the U.S. Army Corps of Engineers for regulatory
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purposes (U.S. Army Corps of Engineers 1987).
Great Lakes wetlands differ from other Basin wetlands in that they are shaped by large lake
processes, including waves, wind tides and especially long and short-term water level
fluctuations. The fluctuating water levels result in a constant shifting of the communities in the
wetland. Many have adapted to this constant fluctuation, and indeed require it to eliminate
stronger competitors that thrive under more stable conditions.
Accordingly, Great Lakes wetlands can be classified based on how they are influenced by Great
Lakes processes. The Lake Erie Water Level Study (International Lake Erie Regulation Study
Board, 1981), identified the following seven wetland types.
Open shoreline wetlands usually exist as a fringe of aquatic plants adjacent to the shore. That
fringe has expanded inland or lakeward in response to lake effects such as wave action and
changes in lake levels. The dominant vegetation is usually emergent, but submergent plants can
also be present and do not necessarily border on a shoreline. Examples of this wetland type are
the north shore of the Inner Long Point Bay on Lake Erie and sections of the Detroit River
shoreline in the vicinity of Fighting Island.
Unrestricted bays are characterized by a marshy fringe along a bay shoreline. These sites are
afforded some protection from such lake effects as wave action. Depending on its size and
depth, the whole bay could be vegetated. Submergent plants can be a part of those vegetative
communities. This wetland type also includes typical open shoreline areas that are sheltered by
an island or peninsula. Examples of this wetland type are the undiked section of the Ruhe Marsh
of the Detroit River, and Black River Bay on Lake Ontario.
Shallow sloping beach wetlands are areas with very gentle to flat slopes on sand substrates. Very
small variations in lake levels have had widespread effects on vegetation zones. Sand bars, if
present, provide some wave protection. The large sand spit formations of Lake Erie (Long Point,
Presque Isle, Point Pelee, and Pointe aux Pins) and Lake Michigan (such as Cecil Bay Marsh)
constitute most of this wetland type.
River deltas are low islands and shallow zones formed by sedimentary deposits at a river mouth.
The normally gentle slope allows the extensive shifting of vegetation zones when water levels
fluctuate. The only wetlands identified as this type are the large St. Clair River delta along the
northern edge of Lake St. Clair and the mouth of the Salmon River on eastern Lake Ontario.
Restricted riverine wetlands are characterized by marsh vegetation bordering a river course. The
extent of the vegetated wetland is often restricted by a steep backslope on the landward side and
the deeper water of the river channel on the other. The Grand River Marshes, the Portage River
Marshes and the Sandusky River Marshes of Lake Erie are examples of restricted riverine
wetlands.
Lake-connected inland wetlands are typified by the presence of a barrier beach or ridge that
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restricts the outlet to the lake and also provides protection from wave action and other
disturbances. Such wetlands can have a definite steep backslope or a gradual slope permitting
some shifting of vegetation zones with changes in water regime. This type of wetland will have
a connection to the lake, but a stream or groundwater discharge from its drainage basin could
also contribute to its water supply. The Big Creek/Holiday Beach Marsh and Hillman Creek
Marsh on Lake Erie, and Oshawa Second Marsh, Deer Creek Marsh and Sandy Creek Marsh on
Lake Ontario are examples of this wetland type.
Protected (or Barrier beach) wetlands are separated from the lake by an unbroken natural barrier
beach or ridge. The natural wetlands and some of the diked wetlands obtain their water from
inland groundwater discharge, streams, and, at times, from the lake, when the wetland floods
during storms. There is some seepage of water through dikes, which can be magnified by
extremes in lake levels.
The diked, managed wetlands of the eastern Lake St. Clair and western Lake Erie shorelines and
Cranberry Marsh, Port Bay, Beaver Creek and Red Creek Marshes on Lake Ontario are examples
of protected wetlands.
Other inshore habitats
Outside of wetlands, there are a range of inshore habitats characterized by being permanently
underwater. These include:
Areas sheltered from wave and wind effects of the lake such as lagoons and embayments.
Estuaries, which in addition to being sheltered from lake effects, are characterized by the
flow of nutrients, organic matter and sediments from upstream. The temperature and
chemical regime of water in estuaries also often differs from that of the lake.
Areas where the lake bed gradient and/or the substrate change abruptly such as in shoals,
reefs and trenches.
2.3 Shoreline
At the water's edge the Great Lakes provide a wide variety of habitats. Habitat type is
determined by shoreline topography, substrate and geology, and by the operative forces of erosion
and deposition in which the orientation to the prevailing wind can play a significant role.
Sand Dunes
Where onshore prevailing winds combine with the transport of sandy sediments in the lake,
freshwater dunes occur. The dunes are uniquely associated with a number of communities
including interdunal wetlands, jack pine barrens and sand beaches, and open dune communities
varying in composition from north to south and east to west.
Lakeplains
Lakeplains occur where the ancestral Great Lakes occupied a different basin than those present
today. Those former lakebeds are characterized by low topography with sandy, silty, or clay soils
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and a high water table. The major topographic features are linear sandy beach ridges that were
formed as the lakes receded in incremental stages. Around the southern Lakes, these areas
supported extensive prairies and savannas, sand barrens, and coastal plain ponds (Nature
Conservancy, 1994).
Although the lakeplains may extend some distance back from the shore, natural hydrological
cycles associated with groundwater flow and lake level fluctuations play a key role in
maintaining habitats for rare communities. They are also linked to the lakes in that they play an
important (historical) role in floodwater retention both from precipitation and high lake levels;
and function as ecological backstops during high lake levels when species and communities from
the coastal wetlands may migrate inland to survive flooding (Nature Conservancy, 1994), They
are also a significant source of fine materials that erode to the lakes in tributary floods and
contribute to the sand and clay components of littoral drift.
Other typical shoreline habitats include emergent bars and spits, and beaches of cobble, gravel,
and sand, bluffs and bedrock shores.
2.4 Tributaries
Tributaries contribute water, chemicals, organic materials and sediments, to the lakes and are
habitat for anadromous species.
The range of tributary habitats depends upon the size, slope, substrate, geology and land-use in
the drainage basin, groundwater characteristics, climate, and the nature of the terrestrial
vegetation.
2.5 Connecting Channels
Connecting channels share characteristics of both tributaries and lakes. Like tributaries, they are
flowing water habitats. Although flows in the St. Marys and St. Lawrence rivers are controlled,
the cycle of water level fluctuations corresponds, more or less, to that of the upstream lakes; the
amplitude of the fluctuations is less and high water is later in the summer than that of the
tributaries. Their trophic status and planktonic communities largely reflect surface water
conditions in the upstream lake.
The shallowness and current which characterize connecting channels result in earlier spring
warming than in lakes. The current also promotes mixing, giving a more homogenous water
quality and better oxygenation, although mixing, at least horizontally, is not always complete.
For example, the Detroit River flows by Windsor half brown and half blue. Nevertheless, the
comparatively warm, well-oxygenated currents carrying sediments and nutrients lead to significant
biochemical activity, some improvement of water quality, and high productivity in shallow waters
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and wetlands in connecting channels, generally. The channels provide a broad diversity of
habitats in close proximity to one another and include many of the habitat types found in the
Great Lakes proper (Atkinson, unpublished).
2.6 Inland Habitats
Both wet and dry inland habitats of the Great Lakes play a significant role in the chemical and
flow regime of the ground and surface water that eventually flows into the lakes. The quality
of the vegetation communities determines the rate of erosion and thus the amount of sediments
transported into the lakes. They also provide nesting sites for birds associated with lake
communities (e.g. the bald eagle).
The climate of all inland habitat types in the region is affected by the Great Lakes themselves.
Geomorphically, the most important historic factor in shaping habitat types was the glaciation.
The terrestrial habitats include a wide variety of forest types, most of which are sub-types of the
northern mixed deciduous forest. Isolated prairies, savannas and sand barrens also occur in the
Basin. The inland aquatic habitats include a wide variety of fens, as well as bogs, marshes, wet
meadows and forested swamps, and a variety of pond and lake types.
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3.0 Ecological Significance of Habitat
Types
The fundamental importance of habitats comes from the fact that they are necessary for all life.
For every species one or more specific habitats are necessary for its survival and reproduction.
In this sense, habitat is a way of regarding the ecosystem from the perspective of one or more
of the species that live in it. This section examines some of the important functions that habitats
fulfill.
3.1 What's Important: Indicators of Significance
Habitat preservation and rehabilitation must take into account habitat functions and
characteristics. Decisions about where to set priorities in habitat conservation, implicitly or
explicitly, are based on some ranking or selection of these functions and characteristics.
The following functions and characteristics are discussed in this section:
Role in nutrient cycling
Productivity
Influence on water quality and quantity
Role in life cycle of species
Biodiversity
Indicator species
3.1.1 Role in Nutrient Cycling
Several nutrient-related functions need consideration when evaluating the role of different habitat
types in the nutrient cycle. Neither the quantities of nutrients at each stage in the nutrient cycle
nor the linkages between the various habitats are well known. Table 1 summarizes values based
on professional judgement and tries to integrate both rates and area-weighted rates.
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Table 1: The Nutrient Cycle in Great Lakes Habitats—summarizing values based on
professional judgement and trying to integrate both rates and area-weighted rates.
Relative Importance: L=Low, M=Medium, H=High
Habitat types
Open -Lake
Inshore
including
wetlands
Connecting
channels
Tributaries
Shoreline
Inland
habitats
Nutrient Uptake
From mineral
substrate
L
H
M
H
L
H
Nitrogen
fixation
L
H
L
L
M
H
Nutrient Cycling
Dissolved in water
[uptake]
L
H
H
H
M
LtoH
Organic matter [rate of
decomposition]
L
H
L
M
L
H
Nutrient Transfer
to other
habitats
L
L
H
H
H
H
to sinks
H
H
L
H
M
M
Nutrient uptake
What quantity of new nutrients do each of the habitat types take up from the two primary sources
- the mineral substrate and the air? In habitats with rooted plants - all but open-lake - some
uptake of nutrients from the mineral substrate takes place. In terrestrial habitats, plant roots draw
on the in situ geological substrate, while in the aquatic habitats the major source of mineral
substrate nutrients are sediments brought by the action of water currents and waves. Sand dune
communities also draw from sediments borne by the combination of water currents and wind.
The uptake of nutrients from mineral substrate for each habitat type has not presently been
quantified. Fixation of nitrogen from the air is limited primarily to terrestrial habitats, with the
notable exception of certain algae, and rates are not known.
The transport of nutrients between habitats is not completely quantified. A major source of
movement is water transport of organic matter and dissolved nutrients. Dissolved nutrients are
taken up by phytoplankton and plants in the water. Their nutrient uptake is limited by plant
distribution and abundance which in turn is limited by the availability of light. Again,
comparative numbers are not available for the different habitat types.
The breakdown of organic matter - releasing nutrients for new life - proceeds at different rates
in different habitats. In aquatic habitats, the limit is usually the oxygen content of the water.
As a result, turbulent, well-oxygenated tributaries, connecting channels, and inshore areas exposed
to breaking waves, can sustain higher turnover of organic matter. In Great Lakes terrestrial
habitats, the turnover of organic matter is relatively slow. Definitive, comparative rates for
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different habitat types are not available, however Wetzel (1992) reported that wetlands occupy
a very small portion of the drainage basins of the upper Great Lakes with deep, open pelagic
waters. The regulatory influences of wetlands to nutrient loading and as a source of dissolved
organic matter increase in the lower Great Lakes but are relatively small in comparison to those
of smaller inland waters.
Several nutrient sinks operate in the Great Lakes basin:
Transport out of the basin (e.g., via the St. Lawrence)
Release into the air (for nitrogen)
Storage in sediments (e.g., lake bottom)
Storage in living biota
Storage in detritus and other dead matter (e.g., peat bogs)
With more information on the dynamics of the nutrient cycle in the Great Lakes it would be
possible to identify habitat types that make a major contribution to the nutrient cycle. Habitats
that can absorb extreme fluctuations - especially an abundance of dissolved nutrients and dead
organic matter - without suffering degradation (e.g. anoxic conditions in eutrophic lakes) are
clearly performing an important function for the ecosystem. On the other hand, the natural
condition, even now, in many Great Lakes habitats is usually one of nutrient limitation. Thus,
the preservation of species able to extract nutrients from the substrate and water column, cycle
nutrients rapidly or thrive under nutrient limitations, and the habitats that support them also
becomes important.
3.1.2 Productivity
The primary productivity of Great Lakes habitats varies greatly. Highest productivity is found
in the connecting channels (Atkinson, unpublished) and inshore habitat, especially in wetlands
(Edwards et al. 1989). Table 2 summarizes current knowledge of biological energy production
and transfer based on professional judgement and tries to integrate both rates and area-weighted
rates.
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Table 2: Energy Cycle in Great Lakes Habitats—summarizing values based on professional
judgement and trying to integrate both rates and area-weighted rates.
Relative Importance: L=Low, M=Medium, H=High
Habitat types
Open-Lake
Inshore
including
wetlands
Connecting
channels
Inland
habitats
Tributaries
Shoreline
Terrestrial
Primary
Productivity
LtoM
H
M
MtoH
M
M
LtoM
Output of organic
matter to other
habitats
L
MtoH
H
LtoM
H
LtoM
MtoH
Input of organic
matter from other
habitats
MtoH
MtoH
M
MtoH
MtoH
LtoM
L
Output of organic
matter to sinks (e.g.
peat bogs)
L
M
LtoM
H
LtoM
L
LtoH
Materials and energy transfer occurs primarily through detritus carried by water currents and,
within the open lake, by gravity. There is also some transfer via fish such as salmon, from open
lakes and littoral zones into tributary streams. The extent of all such transfers has not been
quantified.
Primary production is a measure of the growth of photosynthetic organisms, and represents the
forage base serving as the foundation for all other species on higher tropic levels. Wetlands
provide food for migrating birds, who use the local production to replenish their energy reserves
for the next flight stage along their migratory route.
However, the conditions that limit productivity in many habitats (nutrients, oxygen, temperature,
light) also create the niches to which species have adapted. Maximizing the productivity of all
habitats (for instance through nutrient additions to oligotrophic systems) generally comes at the
expense of overall species diversity. Recent reductions in the productivity of the lakes as a result
of reduced human nutrient loadings have raised the question of what productivity goals to
manage for (Nielsen et al, 1993). One option is to simply manage to protect the natural species
assemblage, letting them dictate the productivity goals.
From the point of view of habitat protection, highly productive habitats that serve as foraging
places for species from other adjoining habitats are "local engines of growth" and might be
considered priorities for protection. Coastal wetlands/marshes are principal examples of this.
Physical (Kinetic) Energy Conversion
Healthy habitats and their resident communities buffer, transform and use the kinetic energy of
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the elements. In this function they protect the land from excessive erosion and the subsequent
sedimentation elsewhere. Examples are trees anchoring the soil, streamside vegetation protecting
the banks of tributaries and coastal wetlands buffering the effects of waves, wind, high water
levels on the shore.
Some plant communities associated with habitat types even require these energy inputs for their
survival. For instance, coastal wetlands require water level fluctuations in a range of periodicities
to maintain their vigor and biological diversity.
The physical energy of the elements also results in the transport of sediments. Some habitat
types are characterized by their reliance on continued sediment transport. Most notable are the
coastal dunes where the primary dune communities depend on ongoing supply of new sand
delivered by a combination of coastal currents and on-shore winds. Coastal wetlands also derive
some of their nutrients and consequent vigor from sedimentation. For other habitats, such as
rocky shoals or gravel beds in tributaries, sediments degrade the habitat for spawning fish. The
continuing high levels of sedimentation as a result of human activities, would seem to put a
premium on habitats that can incorporate sediments while retaining their vitality.
Again, no comparative figures are available on the amount of energy or sediments habitat types
can absorb or deflect.
3.1.3 Influence on Water Quality and Quantity
Habitats influence water quality, water flows and levels, and ground water recharge.
The maintenance of water quality is a function of productivity and the ability of the biota to
utilize nutrients and convert organic matter in any one habitat. Not surprisingly, inshore areas,
connecting channels and especially wetlands are most effective in this role. However, their
ability in this respect has limits, and exceeding these limits leads to degradation and a reduction
in nutrient absorption capabilities. Figures on the range of capabilities and limits among habitat
types are not currently available.
The removal of non-biodegradable toxic chemicals, such as heavy metals, proceeds via the
incorporation of the toxic chemicals into organic matter and the subsequent storage or deposition
of that matter where it is no longer available for living organisms. Alternatively, toxic chemicals
may be deposited directly to lake and river bottoms with sediments. Sedimentation occurs where
water currents become slower, such as where tributaries enter lakes or among the vegetation of
wetlands. Neither of these two routes are particularly conducive to the long-term viability of the
species or habitats accumulating the toxic chemicals. Nevertheless, habitats that function as
contaminant sinks, do serve to moderate the immediate effects of toxic chemicals by removing
them at least temporarily from circulation.
The role of inland habitats in maintaining water quality is perhaps overshadowed by their
importance in regulating water flows and levels. From a basin-wide perspective, the inland
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habitats are the principal collectors of precipitation for the basin, and as such the ability of forests
and wetlands to store and release water is critical to moderating tributary and groundwater flows
to the lakes (Nature Conservancy, 1994). Inland habitats moderate tributary flows, reduce erosion
and sedimentation associated with flooding, and thus moderate the seasonal and long-term
fluctuations of lake levels.
3.1.4 Essential Habitats
Many animal species move between different habitats, with periods ranging from daily through
seasonally to once or twice in their life cycle. In this way, habitats other than the one they are
normally associated with, can play a critical role in the survival of the species, especially when
normally dispersed populations concentrate in very small areas. In such a case, this habitat
becomes far more important than what is suggested by the community of species that are more
permanent residents. Examples of several different kinds of periodic use follow.
Migration stopovers
Historically, the marshes of the Detroit River, Lake St. Clair, Long Point and Western Lake Erie
have been an important resting and feeding stop for the eastern population of canvasback duck,
which winters on the Atlantic Coast. This population declined from 400,000 birds in the early
1950s to less than 147,000 by 1960 and has not recovered to its former levels.
The canvasback duck has rigid habitat requirements and behavioral traits that limit its adjustment
to environmental change. It does not tolerate disturbance by boat traffic and depends strongly
on wild celery. Densities of wild celery tubers decreased by 72% from eutrophication,
sedimentation, carp, and pollution at two of five locations where ducks once fed between 1950
and 1985 (Schloesser and Manny, 1990; Kahl 1991).
Several authors have suggested that the decline in canvasback numbers is at least partially linked
to the reduction in forage on their migration routes (Bellrose and Crompton, 1970; Mills et al.,
1966; Trauger and Serie, 1974).
Spawning and nursery
Many of the fishes of the open lake move to the shallow waters or tributaries to spawn. In this
respect, their needs are very specific - a certain kind of substrate, a certain amount of current,
depth and temperature and within a narrow time-window. Often they return to the same places
where they hatched. In a manner similar to waterfowl, during spawning a widely-dispersed
population becomes concentrated in a habitat of relatively small size. For these populations,
these spawning habitats become far more important than their relative size would suggest.
Nesting
While bald eagles have attracted attention, mostly because of the effects of toxic chemicals on
their reproduction and development, it has also become apparent that reestablishing viable
populations of eagles in the Great Lakes requires more than clean water. Nesting adult eagles
use coniferous perches that are isolated from human disturbance (Bowerman and Giesy, 1991).
14
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A survey of all the Great Lakes found that 34% of the coast is unsuitable as eagle nesting habitat
(Bowerman, 1993). A separate study on Lake Erie found that bald eagles were already using
most of the good to excellent sites, which make up only 12% of total potential sites. In this case,
the sensitivity to disturbance and the large forage area require the protection of extensive coastal
habitat, if bald eagles are to play more than an isolated and infrequent role in the ecosystem.
These three examples illustrate that species will use habitats in ways that do not conform to a
habitat classification system, and that therefore the preservation of species such as the bald eagle
needs the protection of a variety of habitats that do not at first glance appear to be linked.
Of special importance are habitats where a large part of the population gathers periodically in a
limited area, more so when there do not appear to be alternative habitats to which these
migrations may shift if the favored habitat becomes degraded.
3.1.5 Biodiversity
The diverse forms of animals and plants associated with different habitats have received much
attention, and is a reason, along with primary productivity, given for habitat preservation (e.g.
The Nature Conservancy, 1994). For purposes of evaluating habitats in this paper, two common
measures of biological diversity have been separated for clarity's sake.
Richness
One measure of biodiversity is the number of species or unique community types found within
habitat. A greater number of species, particularly endemic species, is generally an indicator of
higher quality habitat. For example, as eutrophic and mesotrophic systems become degraded,
species numbers decrease.
However, the degradation of coldwater oligotrophic systems, for example the addition of nutrients
to Lake Superior, generally results in an increase in the total number of species (Tom Busiahn
pers. comm.). Consequently, species richness cannot be used as an absolute indicator of habitat
quality, in the same manner that higher productivity is not always a sign of higher quality habitat.
This phenomenon complicates the interpretation of trend data and comparisons among habitat
types.
Nevertheless, the comparative species richness of habitats does give some indication of their
value in combination with other information about the habitat. Unfortunately, not enough data
are available on species richness in the various habitat types to make meaningful comparisons.
Rarity
Rare and endangered species often have very specific habitat needs. The number of rare species
depending on a particular habitat type is a further indicator of habitat significance. Preserving
species and community richness at the global level requires priority protection for habitats that
host globally rare species. At other levels of priority, it also means preserving the habitat of
species that have become rare in the Great Lakes basin or in one or more of its subregions.
Aquatic Habitat and Wetlands - SOLEC Background Paper 15
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The U.S. Fish and Wildlife Service (1993) has compiled a list of 22 endangered and/or threatened
species that are potentially affected by Great Lakes water quality. Another seventy-one species
in the Great Lakes Watershed are candidates for designation as endangered or threatened species.
A list of rare and imperiled elements compiled by the Nature Conservancy (1994) is especially
useful because it shows what proportion of the rare and imperiled elements is found in each
habitat type. The Conservancy cites the network of state and provincial natural heritage programs
which have identified 131 elements within the Great Lakes basin that are critically imperiled (22),
imperiled (30), or rare (79) on a global basis. Of these globally significant elements, 31 are
natural ecological community types; the rest are individual species, subspecies or varieties
including 49 plants, 21 insects, 12 mollusks, nine fish, five birds, three reptiles and one mammal.
Additionally, 12 natural community types are recognized that, while not globally rare, form
major components of the basin's landscape and support a wealth of biological diversity that is
important to the basin's ecological integrity. The estimates of the proportion of globally rare
species and communities found in various Great Lakes habitats is shown in Figure 1 (Nature
Conservancy, 1994).
Coastal
Marsh
Coastal Shore
(28.0%)
Inland
Terrestrial
(8.0%)
Tributaries
(15.0%)
Open-like
(S.0%)
Inland
Wetland
(18.0%)
Lakeplaln
(22.0%)
Figure 1: Estimated Proportion of Great Lakes-Unique Biodiversity Elements Found in Great
Lakes Habitats
This figure shows the distribution of species and communities that are found either exclusively
or primarily in the basin, or have their best representation in the Great Lakes Basin, among the
ecological systems that support them. It confirms that the coastal systems (marshes, shores and
lakeplains) contain a disproportionate amount of the unique biodiversity of the Great Lakes. Note
that The Nature Conservancy's data tends to be weaker in wet environments compared to dry.
Thus the biodiversity (and its significance) in Great Lakes aquatic, nearshore, shoreline, and
wetland areas may actually be greater than that published in the report upon which Figure 1 was
based.
In isolation, rarity as an indicator of habitat value leads eventually to a view of preservation as
masking the value of representative species in creating and maintaining a healthy ecosystem.
Thus, rarity too, is better combined with other indicators to give a rounded view of the
comparative value of any particular habitat. Rarity, reflected in state/provincial Natural Heritage
inventories, used as one data source among several, and cast in the context of a broader analytical
16
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process, helps protect productive ecosystems rather than just rare species.
3.1.6 Indicator Species
Healthy populations of diverse native species are one of the best indicators that habitats are of
optimum quality. Accordingly, it may be simpler to monitor the health of selected indicator
species rather than trading off difficult-to-compare criteria. By choosing a suite of species that
require a broad range of high quality habitat types, it may be possible to read ecosystem health
more accurately than measuring many attributes of different habitats in order to make
comparisons that may be controversial. However, species populations are affected by other
factors such as disease, predation and harvest, that are not directly linked to habitat quality.
Thus, using a small number of species as "canaries" for the habitat needs of most or all species
will still require some level of complementary data gathering on habitat quality. Impacts limited
to subtle changes in the lower trophic levels (e.g. relative composition of zooplankton species)
while the top trophic level is relatively unaffected could be harbingers of more profound changes
later on. Programs like EPA's EMAP are trying to set up this sort of monitoring effort.
3.2 The Unique Role of Coastal Shore/Coastal Wetlands
Of all the habitat types, the coastal shore and the coastal marshes, rank most consistently high
for all indicators of ecological and biological significance. The only exception would seem to
be that it does not provide a home for a high percentage of the basin's globally rare species and
communities (Nature Conservancy, 1994).
Although relatively small, the inshore zone concentrates much of the biological productivity and
richness of the Great Lakes. The inshore zone plays a critical role in absorbing nutrients, organic
matter and sediments, and through its high productivity removes some toxic chemicals. Coastal
wetlands are uniquely adapted to and even require fluctuating water levels to maintain their
vitality. Their productivity provides forage for many species from other habitats - animals from
the land, including insects, reptiles, amphibians, mammals and migrating birds, as well as, sub-
adult fish that subsequently migrate to the open lake.
The productivity and diversity of the inshore zone stem from the interaction of the water with
land. In comparison to both the land and the open lake, the inshore zone has extra dimensions
in determining the fine gradations of habitat type. Here both the nature and topography of the
substrate, as well as the depth, flow, temperature etc., of the water determine the type of
communities that establish themselves.
Besides the incoming solar radiation available equally in all habitat types, the inshore zone
benefits from the energy inputs of water currents, wave and wind. These forces bring dissolved
nutrients, sediments and organic matter in quantities sufficient to ensure that nutrients do not
limit productivity to the same degree they do terrestrial communities. At the same time, the
combination of currents, waves and solar radiation ensure good circulation and the resulting
Aquatic Habitat and Wetlands - SOLEC Background Paper 17
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oxygenation. The greater warmth of inshore waters allows a higher metabolic rate and thus also
contributes to overall productivity. Even when water and wind destroy the vegetation, this
ultimately benefits the wetland by resetting succession and maintaining the highly productive,
herb dominated system (Nature Conservancy, 1994). To the degree that connecting channels, and
tributaries include a high proportion of shallow water inshore habitat, this discussion applies to
them as well.
Having described the habitats of the Great Lakes, as well as their ecological and biological
significance, it is now appropriate to examine their current status.
18
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4.0 State of the Habitats
More than 200 years of European settlement have reduced the size and extent of many Great
Lakes habitats and impaired the functional integrity of many that remain. The Great Lakes
contain a mosaic of types and quality of habitat: a healthy habitat type in a given Lake can
coexist with another that is not at all healthy, while the opposite situation may prevail in another
Lake. Thus, habitat area figures, even when available, do not allow accurate comparisons of
areal extent of habitat types, especially across jurisdictions. Conveying habitat status remains
largely descriptive and anecdotal. This section describes the present state of the habitats as a
whole and on a lake-by-lake basis.
4.1 Overall Quantity and Quality by Habitat Type
The ecosystem significance, quantity and quality of each habitat type has been summarized in
Table 3. Similar tables have been prepared for each lake in the sections that follow.
All the tables show the main habitat types discussed in Section 2. Wetlands are included both
under inshore, shoreline and inland habitats. The categories across the top of the table are
explained as follows:
Ecosystem function is a summary of relative role in nutrient cycling, of influence on
water quantity and quality and of importance to life cycle of species.
Productivity assesses the production by plant communities found in the habitat.
Rarity of Species and Communities gives an indication of the number of globally rare
species found in the habitat type.
Quantity is a measure of the total area currently occupied by the habitat, relative to the
average area occupied by all other habitat types.
Loss is the amount of habitat that has been lost or fundamentally altered since the
beginning of European settlement.
Quality reflects the health of the remaining habitat.
Relative Significance is the combined score of all the individual categories.
Scoring is on a five-part scale from low to high. For the overall Great Lakes score, each habitat
is simply compared to all the other habitats to arrive at its relative ranking. For the individual
lakes, each habitat is also compared with the same habitat in all the other lakes to arrive at a
composite score.
Aquatic Habitat and Wetlands - SOLEC Background Paper 19
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Given the lack of knowledge about many of the parameters on which the scores are based, the
potential for differences of opinion on individual scores is large. In other words, the scores are
very much judgement calls. However, the usefulness of the exercise is fourfold:
It gives relative overview of the status of the habitats and those which are most critical
to the ecosystem.
It provides a focus for discussion of the status and role of habitat types.
It assists in identifying knowledge gaps.
Its categories are one possible combination of criteria by which to rank habitats. As such
it can serve as the basis for a discussion on how to set habitat preservation priorities.
The discussion on setting priorities can also examine the question of relative significance. The
approach of the Nature Conservancy places greatest value on high-quality habitats supporting rare
species and communities. While this approach has its merits, a case can be made for protecting
high-quality habitats, which are still so extensive that-their species have not become rare. It is
also less difficult to protect and preserve than to replace lost habitat.
Table 3: Ecosystem Significance and Quality of Habitat in the Great Lakes—summarizing
values based on professional judgement and trying to integrate both rates and area-
weighted rates.
Habitat
Type
Open-Lake
Inshore
Shoreline
Tributaries
Connecting
Channels
Inland
Ecosystem
Functions
Moderate
High
Low
High
High
Moderate
Productivity
Low
High
Moderate
Moderate
High
Moderate
Rarity of
Species /
Communities
Low
Very low
Very high
Low
Low
Moderate
Quantity
High
Low
Low
Low
Very low
Moderate
%Loss
Low
High
Moderate
Moderate
High
High
Quality
Moderate
Low
Moderate
Low
Low
Moderate
Relative
Signifi-
cance
(n/r)
(nit)
(n/r)
(n/r)
(n/r)
(n/r)
(n/r indicates no responses from reviewers)
Open-Lake
While the open-lake habitat has remained virtually unchanged in size, its quality has been
impaired. Nutrient concentrations in the lower Lakes have been reduced from their highs of the
1960s and 1970s. As a result growth rates of nuisance algae have also been reduced. However,
agreement on ideal long-term nutrient levels has not been reached (Nielson et al., 1993). Locally,
such as in many Areas of Concern, nutrient levels are still too high, leading to oxygen depletion
and impaired fauna. ("Areas of Concern" are the 43 Great Lakes toxic "hotspots" identified by
20
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the U.S. and Canadian governments based upon the recommendations of the International Joint
Commission).
The presence of toxic chemicals in the water continues to affect the health of fish and bird
predator populations (LEP, 1994). Basin-wide data on the effect of siltation, especially as it
degrades spawning and benthic habitat in the open lake are not available.
Biological sources of degradation are overfishing and the introduction of non-native species, such
as the zebra mussel which have out-competed endemic filter feeders and altered the substrate and
water clarity especially of parts of Lake Erie. Koonce (1994) argues that stresses associated with
biological factors have, in fact, caused more severe degradation than physical and chemical
stresses in the lake ecosystems. Several of the endemic fishes — formerly dominant species —
have been eliminated, and others, such as the shortnose ciscoe and the globally rare lake
sturgeon, now have severely restricted distributions. Although portions of the lakes appear to
support high-quality benthic communities, the overall documentation of the character and quality
of invertebrate biota is still scanty. The Lakes' biotic communities also have not been
systematically described or ranked from a biodiversity standpoint. However, they would
presumably rank as globally rare to imperiled, due to restricted distribution, high level of threat,
ecological fragility, widespread damage and because they are the single largest source of
freshwater in the world (Nature Conservancy, 1994).
Inshore
Throughout the Great Lakes basin, the picture for wetlands is clear: most of the pre-settlement
wetlands, both inshore and inland, have been lost. While the rate of loss has slowed in recent
decades, there is still a net ongoing loss in the quantity and quality of wetlands habitat.
Other inshore habitats have also suffered. Quantitative losses occurred primarily through lakefill
and dredging in urban areas. Qualitative losses have been more extensive and include
sedimentation of spawning grounds, eutrophication, toxic chemicals in the water, changes in the
thermal regime and invading of exotic species. Basin-wide data are not available.
Inland and coastal wetland losses in the eight States at least partially within the Great Lakes
Basin have been disproportionately greater than in many other U.S. regions. Since the 1780s,
Great Lakes Basin States have lost an estimated 34.9 million (59.7%) acres of wetlands out of
its 58.6 million original wetland acres. This compares with an average loss of 52.8% nationwide.
There are an estimated 23.6 million acres of wetland remaining in the eight Great Lakes States,
representing more than 22% of the wetlands within the lower 48 states (Dahl, 1990). In Ontario
south of the Precambrian shield, wetlands once covered an estimated 25% of the landscape. The
total losses in southern Ontario are estimated at 80% (Patterson, 1994), Recent historic losses
of wetlands in the Great Lakes basin have been estimated to be 20,000 acres/year (Great Lakes
Basin Commission 1981). The data are insufficient to estimate the current rate of loss.
Coastal wetland loss estimates from different sources have been compiled for various sections
of the Great Lakes by Bedford (1990). She reports no estimates were found for Lakes Superior
and Huron, but 11 to 100% of the wetlands have been lost in sections of the other three Lakes
Aquatic Habitat and Wetlands - SOLEC Background Paper 21
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and Lake St. Clair.
Compilation of various reports, primarily the Lake Erie Water Level Study (International Lake
Erie Regulation Study Board 1981) and Herdendorf et al. (1981), indicate an approximate total
of 120,000 hectares of coastal wetlands along the U.S. shoreline of the Great Lakes. Table 4
gives a breakdown of U.S. wetland area on each lake, indicating that on the U.S. side, the most
wetland can be found in Lake Michigan. On the Canadian side no comparable data exist for all
the lakes, but Whillans et al (1992) report approximately 25,000 ha of shoreline wetlands on the
Canadian portion of Lake Ontario.
WETLAND %
Lake Ontario-St. Lawrence 6.9
Whitefish Bay 3.6
St. Mary's River 4.4
Lake Erie-Niagara 6.7
St. Clair-Detroit 3.2
Lake Superior 14.5
Lake Michigan 40.4
Lake Huron 20.4
Table 4. Distribution of the approximately 300,000 acres of coastal Great Lakes wetlands in the
U.S. (Sources: Herdendorf et al. 1981 and others). No comparable Canadian data exist.
Wetland degradation results from numerous human activities. Other than direct filling of
wetlands, the most frequently encountered changes are:
sedimentation which lowers penetration of sunlight and displaces some fish species;
loss of hydrological connectivity both to the lake and to tributaries/groundwater;
loss of refugia to which communities can shift during periods of high and low water
levels;
reduced lake level fluctuations will become a major future source of degradation if
management scenarios are implemented;
discharges of pollutants and contaminants which are an immediate stress on water quality
and secondly on biological functions; and
non-consumptive use disturbance which may affect sensitive species.
22
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Often wetlands are subject to numerous concurrent stresses, Herdendorf et al. (1986) note that
the loss of coastal wetlands along the Michigan side of Lake St. Clair has resulted in a loss of
wetland functions and values. For example, public drains installed to improve runoff now occupy
former creek channels, which no longer benefit from the flood water storage, sediment trapping,
and nutrient uptake afforded by the natural wetlands. Nor do the remaining wetlands along the
river mouth and shorelines which have been reduced in size, partially developed (especially on
the lakeward side) and otherwise impacted, have the fish and wildlife value they once had.
Shoreline
The encroachment on shoreline habitats results from agricultural, recreational, urban and
industrial development. Almost half the globally rare species and communities in the basin fall
into Nature Conservancy's (1994) coastal shore and lakeplain types, which correspond generally
to the shoreline category used here. For instance, sand dunes provide habitat for a range of state
and federal threatened and endangered species including piping plover, Pitcher's thistle, Lake
Huron tansy, Houghton's goldenrod, and many others (Cwikiel, pers. communication). On the
former lakeplains, the remnant wet prairies and wet meadows are themselves rare and provide
habitat to a high percentage of endangered species (Cwikiel, pers. communication).
Table 5 shows Bowerman's (1993) estimates of the quality of bald eagle nesting habitat within
1.6 km of the shore for each of the Lakes. He estimates that 34% of the coast is unsuitable
nesting habitat for bald eagles. No similar Basin-wide surveys of the quality of shoreline habitat
for other species exist. The Nature Conservancy (1994) reports that the extensive dunes on Lake
Michigan's eastern shore are largely intact, and the coasts of Lakes Superior and Huron remain
sparsely settled. Basin-wide data on the general condition of shoreline habitats are not available.
Aquatic Habitat and Wetlands - SOLEC Background Paper 23
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Table 5 Shoreline (km) by habitat classification for Bald Eagles on each Great Lake, (after
Bowerman, 1993)
Lake
Superior
Michigan
Huron
Erie
Ontario
TOTAL
Good
km
(%)
2186
(76.5)
624
(32.5)
1975
(65.0)
94
(7.0)
112
(7.8)
4991
(47.1)
Marginal
km
(%)
186
(6.5)
353
(18.4)
319
(10.5)
543
(40.4)
614
(42.8)
2015
(19.0)
Unsuitable
km
(%)
487
(17.0)
942
(49.1)
744
(24.5)
707
(52.6)
710
(49.4)
3590
(33.9)
Total
km
(%)
2859
(27.0)
1919
(18.1)
3038
(28.7)
1344
(12.7)
1436
(13.5)
10596
Tributaries
While loss of tributary habitat is mostly limited to urban areas, quality impairment has been
significant. Impacts have been felt on a wide range: channelization, dredging, damming,
sedimentation, loss of bankside vegetation, eutrophication, increased spring flooding, and toxic
contamination. Large areas of inland forests and wetlands that once served to regulate the
quantity and quality of water flowing into tributaries have been lost. As a result, tributaries pass
on their pollutant and sediment loads to the lakes and their suitability as spawning habitat has
been seriously impaired.
Connecting Channels
The connecting channels have suffered from the same pressures as the inshore habitat, only more
so. Large wetland areas have been lost to agriculture. Urban and shipping needs have led to
infilling, channelization and the building of bulkheads, and a loss of other inshore and channel
bottom habitats. Toxic contaminants have accumulated in sediments and continue to effect
species directly and indirectly. Despite the losses and impairments, some of the basin's most
extensive and productive wetlands and inshore habitats survive in the connecting channels. A
channel-by-channel description of the state of connecting channels follows below.
Inland
Inland habitats have been extensively altered, primarily through deforestation and wetland
24
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drainage for agriculture. Inland wetland losses were included in the figures cited above. Habitat
quality has been impaired by the effects of air pollution on forests, and discharge of wastes into
tributaries that flow through inland wetlands.
4.2 Lake Superior
The dominant habitat of Lake Superior is the very large, deep and oligotrophic open lake. Steep
shorelines, and the deep lake have created little room for extensive inshore shallows. However,
many of the Lake's tributaries have extended deep-water estuaries or extensive shallows off their
mouths, offering excellent shallow-water habitat (Lawrie, 1978). Nutrient input from the
tributaries is low, and so is the primary productivity of the lake (Iwachewski, 1994). Shorelines
vary from steep rock cliffs through low-lying clay and gravel bluffs, to sheltered embayments
and wetlands. The inland habitats are divided into seven ecoregions, the northern and eastern
areas dominated by fir spruce and the southern and western covered by maple, aspen and conifer
mixed forest (LSBP, 1993).
Habitat loss and impairment have resulted from industrial operations, forestry and mining
activities, sewage disposal, road and railway construction, and deposition of airborne
contaminants, much of it from outside of the basin (Busiahn, 1990). Lawrie (1978) reports that
many shallow-water benthic environments were ruinously affected by the deposition of sawdust
and other woody, allochthonous materials, because of logging in the late 19th and early 20th
centuries. The recent discovery of algal mats covering several isolated rock shoals (Edsall et al.,
1991) suggests that current human activities are continuing to have an impact on spawning
habitat. Log drives and stream channelization resulted in riverine habitat loss across the north
shore (LSBP, 1993). Hydroelectric development has resulted in habitat loss and degradation from
fluctuations in water levels and blockage of traditional migratory routes by dams on several
rivers. The Nipigon River is perhaps the worst example of this (LSBP, 1993),
Lake Superior has the highest water quality of all the Great Lakes. The trend shown over the
last 60 years of water chemistry data for Lake Superior is best described as stable, in contrast
to the recent changes in lakes Erie and Ontario. One of the major concerns is atmospheric
deposition, which accounts for about 90% of some toxic chemicals entering the Lake. In seven
Areas of Concern, water and habitat quality have been locally impaired, resulting in problems
such as a loss of wetlands, contaminated sediments, degraded benthic communities and
restrictions on fish consumption. In the four Canadian AOCs, one of the primary sources of
degradation has been pulp and paper mills (Iwachewski, 1994).
While Lake Superior as a whole is in relatively good condition, some inshore and tributary
habitats have been degraded to the point where open-lake populations have been affected. Table
6 gives an overview of the ecosystem significance and the state of the habitats for Lake Superior.
An explanation of the ranking criteria and scoring is found in Section 4.1, Overall Quantity and
Quality by Habitat Type.
Aquatic Habitat and Wetlands - SOLEC Background Paper 25
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Table 6: Ecosystem Significance and Quality of Habitat in Lake Superior-summarizing
values based on professional judgement and trying to integrate both rates and area-
weighted rates.
Habitat
Type
Open-Lake
Inshore
Shoreline
Tributaries
Inland
Ecosystem
Functions
low
high
low
high
moderate
Productivity
very low
moderate
low
moderate
low
Rarity of
Species /
Communities
moderate
moderate
moderate
moderate
moderate
Quantity
very high
low
very high
low
high
Loss
very low
moderate
low
moderate
low
Quality
very high
high
high
moderate
moderate
Relative
Signifi-
cance
(n/r)
(n/r)
(n/r)
(n/r)
(n/r)
(n/r indicates no responses from reviewers)
4.3 Lake Michigan
One of the most impressive natural shore types of the entire Great Lakes is the long expanse of
sand dunes along the eastern shore of Lake Michigan. The western and northern shores are
characterized by erodible bluffs and non-erodible rocky shores respectively.
The inshore zone contains extensive wetlands - about 40% of the total in the United States Great
Lakes (Herdendorf et al., 1981). The inshore waters of the lake are generally mesotrophic.
Given the Lake's long north-south axis, climate plays a role in determining the community
composition of the various habitats. The north-south gradation is pronounced enough that
northern Lake Michigan is often grouped with Lake Superior to the Upper Lakes, while the
southern end of the Lake has more similarities with Lakes Erie and Ontario.
This north-south gradation carries over to the impairment and loss of habitat. The south, with
its concentration of agriculture and urban areas, has generally higher levels of nutrients (over 20
ug/1 of phosphorous in some areas) and toxic chemicals than the north. Development in the south
has also led to a greater loss of inshore and shoreline habitat than in the north. In the north,
Green Bay has been impacted most seriously, with high nutrient and PCB levels, and public
health advisories against consumption of several species in addition to the lakewide advisory for
large trout and salmon. Lakewide, degradation of water quality from land use activities and
waste discharge has affected fish spawning in certain areas. Surface waters in Lake Michigan
have higher burdens of heavy metals than any of the other Great Lakes. Table 7 gives an
overview of the ecosystem significance and the state of the habitats for Lake Michigan. An
explanation of the ranking criteria and scoring is found in Section 4.1, Overall Quantity and
Quality by Habitat Type.
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Table 7: Ecosystem Significance and Quality of Habitat in Lake Michigan-summarizing
values based on professional judgement and trying to integrate both rates and area-
weighted rates.
Habitat
Type
Open-Lake
Inshore
Shoreline
Tributaries
Inland
Ecosystem
Functions
low
high
low
moderate
high
Productivity
moderate
high
low
high
moderate
Rarity of
Species /
Communities
(n/r)
(n/r)
(n/r)
(n/r)
(n/r)
Quantity
high
very high
high
moderate
high
Loss
very low
moderate
moderate
(n/r)
moderate
Quality
moderate
moderate
high
low
moderate
Relative
Signifi-
cance
(n/r)
(n/r)
(n/r)
(n/r)
(n/r)
(n/r indicates no responses From reviewers)
4.4 Lake Huron
The diverse shoreline of Lake Huron is the longest of the Great Lakes, its length extended by the
shores of its numerous islands. Rocky shores associated with the Precambrian shield cover the
northern and eastern shores, limestone dominates the shores of Manitoulin island and the northern
shore of the Bruce Peninsula, and glacial deposits of sand, gravel, and till predominate in the
western, southern, and south-eastern portions of the shore. Shoreline and inshore habitats are
correspondingly diverse.
Inshore habitat includes extensive local concentrations of wetlands primarily in sheltered bays
and river mouths, totalling about 24,400 ha on the United States side (Herdendorf et al, 1981 and
others) and, based on an incomplete survey, at least 12,000 ha on the Canadian side (Liskauskas,
1994). Saginaw Bay, the DeTour/Drummond Island/Les Cheneaux Islands areas and Severn
Sound have especially large wetland areas. Matchedash Bay is a Class 1 provincially significant
wetland. Other inshore habitat is less well-documented on a lakewide basis. The open lake is
oligo-mesotrophic, its nutrient load lying between that of Lakes Superior and Michigan
(Liskauskas, 1994).
Lake Huron has more islands than any other lake in the world, including Manitoulin Island, the
world's largest in freshwater. Manitoulin has more than 70 large lakes that can be grouped into
eight habitat types based on fish species composition.
Neither descriptions nor data on the quantity and quality of inland habitats were available. Little
information on habitat characteristics of tributaries is available. On the Canadian side, the Severn
watershed is characterized by extensive wetlands, while the lower reach of the Spanish River is
an area of deep even flow, with some abundance of aquatic plants in the estuary. Both of these
Aquatic Habitat and Wetlands - SOLEC Background Paper
27
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rivers are receiving intensive study.
Habitat loss and degradation have not been systematically documented except locally. In
Saginaw Bay, waste discharges and waste heat from power plants have reduced fish habitat.
Phosphorus concentrations exceed 20 ug per litre and are some of the highest values reported in
the Great Lakes. Eutrophication has also affected habitat in Severn Sound, Collingwood and
Spanish Harbours, In the latter two, sediment contamination and dredging have contributed to
habitat impairment. In the Spanish River, fluctuations in water levels, shoreline alterations and
deposition of bark and fibre are cited as sources of habitat degradation (Liskauskas, 1994).
In comparison to Lakes Michigan, Erie and Ontario, contaminant concentrations in Lake Huron
are low. Only Lake Superior waters are lower in heavy metal concentrations. Nevertheless,
public health advisories exist regarding the consumption of trout from the open lake and all four
Areas of Concern. Table 8 gives an overview of the ecosystem significance and the state of the
habitats for Lake Huron. An explanation of the ranking criteria and scoring is found in Section
4.1, Overall Quantity and Quality by Habitat Type.
Table 8: Ecosystem Significance and Quality of Habitat in Lake Huron-summarizing values
based on professional judgement and trying to integrate both rates and area-weighted rates.
Habitat
Type
Open-Lake
Inshore
Shoreline
Tributaries
Inland
Ecosystem
Functions
low
high
moderate
moderate
low
Productivity
low
moderate
low
moderate
moderate
Rarity of
Species /
Communities
(n/r)
(n/r)
(n/r)
(n/r)
(n/r)
Quantity
high
very high
very high
moderate
moderate
Loss
very low
moderate
low
moderate
moderate
Quality
high
high
high
moderate
moderate
Relative
Signifi-
cance
(n/r)
(n/r)
(n/r)
(n/r)
(n/r)
(n/r indicates no responses from reviewers)
4.5 Lake Erie
Lake Erie is made up of three relatively distinct basins: the shallow western basin, and the deeper
central and eastern basins which are separated by a sill. The entire depth of the western basin
is stirred by wind action, resuspending bottom sediments for filter feeders in the water column
and preventing any lengthy thermal stratification. Historically, benthos has been dominant in the
basin, feeding on the organic load delivered by the Detroit and Maumee rivers. The basin also
provides spawning shoals for fish from the other basins. The central and eastern basins have
lower flushing rates and greater thermal stratification than the western basin. Even before human
intervention, the central basin seems to have had periods of anoxia (LEP, 1994).
28
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Much of the Lake Erie shore is composed of limited beach area at the foot of bluffs that are
composed of silty-elay soils. The loss/degradation of coastal wetlands exacerbates the "stirring"
effect on the clay soils. Erosion of this material results in turbid or milky-colored inshore waters.
In contrast to the inshore conditions, the water is much more transparent offshore. In the central
and eastern basin, the offshore water transparency is typical of oligotrophic conditions. The
wind-fetch in the central basin causes strong along-shore currents and undertows that move
sediment from the bluffs along the shore, building peninsulas (Pelee, Point-aux-Pins, Long Point,
Presquile). The turbidity and shifting of unstable substrates are factors that limit primary and
secondary production in the inshore habitat. Elsewhere in the lake, primary production and
loading of detrital organic material to the littoral zone supports high levels of secondary
production by benthic insects, crustaceans, molluscs and gastropods. The peninsulas shelter
significant remaining wetlands and create bays that provide spawning and nursery habitat for
several fish species (LEP, 1994).
Lake Erie once had very extensive wetlands, especially on the U.S. side, including the 4000 km2
Black Swamp at the Maumee River which has been reduced to 100km2. Significant wetlands on
the Canadian side occur at Dunnville, Rondeau Bay, Long Point Bay and Point Pelee. While
conversion, primarily by agriculture continues, a more widespread problem for wetlands are
agricultural nutrients and sediments. High turbidity prevents the establishment of submergent
vegetation and shifts the fish community from predator to bottom feeder dominance (LEP, 1994).
There are comparatively few areas of rock littoral substrate. Virtually all such habitat has been
encrusted with zebra and quagga mussels, except for areas where waterfowl or fish predation and
ice scour limits mussels to the sheltered sides of rocks. Quagga mussels predominate in the east,
while zebra mussels predominate in the central and western basins. The filtering action of the
mussels has resulted in increased water transparency both inshore and offshore. The fecal pellets
produced by the mussels have provided detrital material to support production of amphipods and
other benthic organisms (LEP, 1994).
Rocky substrates have also been degraded by algal growth and sedimentation, both of which limit
spawning. In the Detroit River, contaminated sediments are thought to be affecting fish eggs.
On the Grand River, dams have limited the upstream migration of walleye.
Over past decades, Lake Erie has suffered from eutrophication, which decimated the benthic
communities of the western and central basins. Although phosphorus loadings have been reduced
below target levels, benthos of the western basin has not recovered, perhaps due to some
combination of oil in the sediments, pesticides and fish predation. In the central basin, the
oxygen demand of the substrate layer has not decreased despite the lower nutrient levels. The
new oligotrophic conditions have led to a decline in the productivity of percid fishes.
Table 9 gives an overview of the ecosystem significance and the state of the habitats for Lake
Erie. An explanation of the ranking criteria and scoring is found in Section 4.1, Overall Quantity
and Quality by Habitat Type.
Aquatic Habitat and Wetlands - SOLEC Background Paper 29
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Table 9: Ecosystem Significance and Quality of Habitat in Lake Erie—summarizing values
based on professional judgement and trying to integrate both rates and area-weighted rates.
Habitat
Type
Open-Lake
Inshore
Shoreline
Tributaries
Inland
Ecosystem
Functions
high
high
low
high
moderate
Productivity
high
moderate
moderate
high
moderate
Rarity of
Species /
Communities
(n/r)
(n/r)
(n/r)
(n/r)
(n/r)
Quantity
high
moderate
moderate
moderate
moderate
Loss
very low
very high
high
moderate
high
Quality
low
low
low
low
moderate
Relative
Signifi-
cance
(n/r)
(n/r)
(n/r)
(n/r)
(n/r)
(n/r indicates no responses from reviewers)
4.6 Lake Ontario
Although Lake Ontario is the smallest of the Great Lakes, it has the largest drainage basin
relative to its size of all the Great Lakes, and is second only to Lake Superior in terms of depth
relative to size. The bottom topography of the lake is relatively smooth with the exception of
a sill which separates the Kingston Basin from the remainder of the lake. This separation results
in unique water quality characteristics in the Kingston Basin (Kerr and LeTendre, 1991).
Eighty-five percent of the lake perimeter is characterized by regular (nearly linear) shorelines
sloping rapidly into deep water (Whillans, 1980). This shoreline configuration tends to lead to
a relatively low biological productivity (Ryder, 1965). Whillans et al (1992) cite a total coastal
wetland area of 32,422 ha for the lake. In the majority of the lake (excluding the Kingston
Basin) the nearshore zone (0 to 10m depth) is found in a narrow 0.5 to 1.5 km wide band. This
represents only 7% of the total surface area. The substrate of the inshore zone consists of
extensive glacial sediment and bedrock overlaid with relatively small, discrete deposits of post-
glacial sediment. Most of this zone is unsuitable for rooted aquatic plants because of exposure
to wave action and large-scale shifts in sediments during storm events (Whillans, 1980). The
notable exceptions to this are Hamilton Harbour, Toronto Waterfront, Oshawa Second Marsh,
Presqu'isle Bay/Wellers Bay, East Lake, West Lake, Ironduquiot Bay, Sodus Bay, and extensive
wetland systems on the east side of Lake Ontario which are all sheltered by barrier beaches or
islands. Lake Ontario's wetlands are not extensive, and most are either in these sheltered bays
or at other river mouths (Mathers, 1994).
In contrast, the shoreline in the Kingston Basin is highly irregular and the nearshore zone (0 to
10m depth) represents 31 per cent of the basin's surface area. The largest areas of shallow water
in the Kingston Basin include the Bay of Quinte, Chaumont Bay, Henderson Bay, and Prince
Edward Bay. The sheltered nearshore zones in all areas of the lake tend to support aquatic
rooted plants and relatively diverse warm-water aquatic communities. The substrate from
30
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Wellington to Kingston is generally bedrock (80%) with occasional deposits of fines in protected
areas (Balesic, 1979).
The shoreline substrates are similar to those of the inshore zone with occasional rock outcrops.
The eastern basin is characterized by bedrock shores. For the most part, the glacial sediments
form bluffs of various heights, interspersed with beaches. Sand dunes are present at only two
locations.
The tributaries of Lake Ontario drain glaciated sediments that were once covered with mixed
hardwood forests. With its large drainage area relative to its size, Lake Ontario's tributaries play
a greater role in transporting nutrients and sediments than they do for other lakes.
The status of the physical habitat is difficult to assess since little historical data is available.
However, several specific examples of habitat degradation are known. Areas where fractured
bedrock and glacial drift are swept clean of fine materials were historically used as spawning
sites for several offshore fish species including lake whitefish, lake herring, and lake trout
(Whillans, 1980). Much of the nearshore habitat in the Toronto area has been destroyed by
mining for construction aggregate and filling or armoring of the shoreline. This has occurred in
the rest of the lake, primarily where urbanization has occurred along the shoreline. Agricultural
land-clearing was widespread in the Lake Ontario watershed during the early nineteenth century.
This led to extensive soil erosion and siltation of stream and nearshore spawning grounds.
Several of the fish species, including lake sturgeon, Atlantic salmon and walleye, which
historically inhabited Lake Ontario migrated up streams to spawn. Numerous dams for saw and
grist mills were constructed blocking upstream migrations of fish (Bridger and Oster, 1981) and
contributed to the decline of these important fish populations.
Lakewide data on the loss of Lake Ontario wetlands are not available, but Whillans (1982)
suggested that losses could be as high as 75% in areas of intensive settlement.
Eutrophication has been one of the most obvious forms of degradation of the aquatic habitat of
Lake Ontario in the past (Christie, 1972). In particular, the water quality of most of the sheltered
nearshore zones has been strongly affected by cultural eutrophication since the 1940's and
possibly earlier. Nuisance algae blooms have resulted in decreased water clarity and reduced the
abundance of beds of rooted aquatic plants in many sheltered nearshore zones, such as the Bay
of Quinte. Consequently, there has been a decline in the abundance of piscivorous fish species
associated with weed beds such as largemouth bass and northern pike (Hurley and Christie,
1977). Despite water quality improvements in many inshore zones such as the Bay of Quinte,
clear waters, rooted aquatic plants, and a diverse fish community have not returned to most of
these areas.
The signs of eutrophication of the open lake and exposed nearshore zones are not as obvious as
in the sheltered nearshore zones. One specific example is the spawning beds in the exposed
nearshore zones which have been degraded by dense mats of Cladaphora, a nuisance algal typical
of eutrophic systems (Whillans, 1980).
Aquatic Habitat and Wetlands - SOLEC Background Paper 31
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Reduced nutrient input during the past decade seems to be shifting the lake towards a more
oligotrophic state (Anonymous, 1992). The algal community composition has changed
throughout the lake, with an 18% reduction in the annual rate of photosynthesis in the 1980's.
Zooplankton production is thought to be 50% lower. Lower production is expected to have
ramifications for the entire food chain, including predatory fish (Mathers, 1994).
Toxic chemicals have also impaired habitat quality. Public health advisories restrict the
consumption of trout and salmon from the lake. Contaminants have found their way into
sediments. In general, harbour and river mouth sediments, which are often also productive
wetlands and spawning grounds, have higher contaminant concentrations than do nearshore and
open-lake sediments. Seven sites, containing heavily contaminated sediments, have been
identified and designated as Areas of Concern.
Warm water outflows from hydroelectric generation plants, and deepwater cooling proposals
have the potential to influence the thermal regime of the lake. The physical impacts of deepwater
cooling at the scale currently proposed are thought to be small (Boyce et al., 1993). Table 10
gives an overview of the ecosystem significance and the state of the habitats for Lake Ontario.
An explanation of the ranking criteria and scoring is found in Section 4.1, Overall Quantity and
Quality by Habitat Type.
Table 10: Ecosystem Significance and Quality of Habitat in Lake Ontario—summarizing
values based on professional judgement and trying to integrate both rates and area-
weighted rates.
Habitat
Type
Open-Lake
Inshore
Shoreline
Tributaries
Inland
Ecosystem
Functions
moderate
very high
low
high
moderate
Productivity
moderate
moderate
moderate
high
moderate
Rarity of
Species /
Communities
(n/r)
(n/r)
(n/r)
(n/r)
(n/r)
Quantity
high
low
moderate
high
high
Loss
very low
high
high
high
Quality
moderate
moderate
moderate
poor
poor
Relative
Signifi-
cance
(n/r)
(n/r)
(n/r)
(n/r)
(n/r)
(n/r indicates no responses from reviewers)
4.7 Connecting Channels
In the connecting channels, the proximity of the opposing inshore zones to one another gives a
greater diversity of habitats within a given area than is generally the case in the lakes. The upper
three channels are characterized by low shorelines and gradients (see Table 11) that favor the
development of extensive wetlands. In the Niagara and St. Lawrence river wetlands are
proportionately less important. The trophic status and planktonic communities usually mirror the
32
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upstream lake, however, local habitat conditions may vary widely from conditions found in the
channels.
Table 11: Physical Characteristics of Great Lakes Connecting Channels
Channel (river)
St. Mary's
St. Clair
Detroit
Niagara
St. Lawrence
Length (km)
97
43
51
56
842
Gradient (m/km)
0.075
0.056
0.018
1.77
0.088
Average Flow (CMS)
2,100
5,300
5,400
5,700
6,700
The connecting channels are often the areas most heavily utilized by humans. It follows that
habitat in all five connecting channels has been impaired. An indication of the degree of
impairment is the designation of part or all of each connecting channel as an Area of Concern.
In addition to the impacts of agriculture, industry and urbanization which affect the lakes, the
connecting channels suffer from physical alterations for shipping, water level management and
power generation. The natural features and major impacts for each connecting channel are
summarized below.
St. Mary's River
Extensive areas of emergent marsh wetland border the lower river. Eighty-three percent of the
land within five km of the river consists of natural forest and wetland (Atkinson, 1994). An
abundance of diverse fish habitats may explain the large number of species (74) found in the
river (Liskauskas, 1994).
Major loss of fish habitat has occurred through the extensive alterations and dewatering of the
St. Mary's rapids. Further habitat loss is concentrated in the northern section of the river, by
Sault St. Marie, where extensive wetland and further fish habitat have been lost to dredging,
filling and shoreline development (Krishka, 1989). Contaminated sediments are concentrated in
the north, and disturbances from shipping negatively affect sediments and inshore habitat.
St. Clair River
The St. Clair is still characterized by its extensive wetlands, most of which lie in the largest
freshwater delta on the earth, where the river enters Lake St. Clair. A total of 4,000 hectares of
emergent aquatic plants are distributed over 15 wetlands. The area is a very important staging
area for migrating birds and fish.
The remaining wetlands represent as little as 30% of what once existed. Drainage for agriculture
has accounted for 92% of these losses (Atkinson, 1994). Extensive bulkheading and infilling
have resulted in the loss of spawning, nursery and feeding sites for fish.
Aquatic Habitat and Wetlands - SOLEC Background Paper
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Detroit River
Excellent fish and wildlife habitat in the lower river includes more than 31 wetlands covering
2000 hectares. About 90% of the original wetlands have been lost (LEP, 1994).
The river is heavily urbanized and industrialized with 86% of the U.S. shoreline occupied by
retaining walls and harbour structures. The dredging, bulkheading and or backfilling of wetlands,
inshore waters, bayous and embayments have resulted in extensive losses of spawning and
nursery areas for fish and wildlife.
Niagara River
The Niagara shoreline is composed of low banks in the upper portion of the river and a deep
gorge cut through sedimentary deposits in the lower river below the Falls. The river and its
tributaries drain wetlands covering almost 5,000 hectares (Atkinson, 1994).
Both sides of the river are intensively used for urban and agricultural purposes. Extensive filling
has occurred in the Buffalo area. Other impairments stem from erosion/sedimentation, removal
of vegetation, human intrusion, toxic materials and disruptions in flow characteristics (Atkinson,
1994).
St. Lawrence River
Initially, the St. Lawrence River flows over bedrock. Many small islands dot the upper reach.
At Cornwall, the substrate changes to clay with low shores of glacial sediments, primarily clay.
Here significant wetlands occur, for example, the two in Lake St. Francis which cover 1,500
hectares.
The single biggest impact on fish and wildlife habitat have been the five dams between Kingston
and Montreal. Below Montreal, that City's waste discharges also play a role in making the river
inhospitable for some species. Along the entire river shoreline, modifications and nutrient
enrichment affect fish spawning and nursery areas (Atkinson, 1994). Table 12 gives an overview
of the ecosystem significance and the state of the habitats of the connecting channels. An
explanation of the ranking criteria and scoring is found in Section 4.1, Overall Quantity and
Quality by Habitat Type.
Table 12: Ecosystem Significance and Quality of Habitat in the Connecting Channels--
summarizing values based on professional judgement and trying to integrate both rates and
area-weighted rates.
Habitat
Type
Open Channel
Inshore
Shoreline
Tributaries
Ecosystem
Functions
Low
Very high
low
moderate
Productivity
moderate
very high
moderate
high
Rarity of
Species /
Communities
(n/r)
high
(n/r)
(n/r)
Quantity
moderate
moderate
moderate
low
Loss
high
very high
very high
high
Quality
poor
high
poor
poor
Relative
Signifi-
cance
low
very high
low
low
-------
land
low
moderate
(n/r)
moderate
high
poor
moderate
(n/r indicates no responses from reviewers)
Summing Up
The habitat loss and degradation is insufficiently documented. Data that would shed light on the
larger picture and its repercussions are almost non-existent. Instead, there are numerous local
studies, split by watersheds, jurisdictions and disciplines. The assessment of the state of the
habitats remains almost entirely anecdotal. However, the sheer number of anecdotes and their
basic agreement allow only one conclusion, that habitat loss and degradation have been very
high, especially in the highly productive and diverse inshore zone and the connecting channels.
By and large, the open Lakes are recovering from the eutrophication of the last decades.
However, many species associated with them remain threatened because the inshore, shoreline
and tributary habitats which they also require have been lost or impaired. The dependence of the
lakes and the species that are associated with them on healthy shoreline, inland and tributary
habitats has been largely neglected. As a result, the impoverishment of these habitats has hardly
registered as a Great Lakes issue.
Most habitat losses to physical changes (e.g. filling, bulkheading, etc.) are likely irreversible.
Losses caused by biological and chemical changes have the potential to be reversed.
Accordingly, it makes sense to focus on stopping the ongoing pattern of loss and impairment in
the present. However, present losses are rarely the large-scale conversion of habitat to other uses.
Instead, degradation is more common, in a variety of subtle guises, that truly require an
ecosystem approach to understand and reverse.
Accordingly, the next section discusses the various types of impact as a basis for assessing the
adequacy of current restoration and protection initiatives.
Aquatic Habitat and Wetlands - SOLEC Background Paper
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5.0 Types of Impact on Habitat
The Nature Conservancy (1994) has grouped sixteen types of impact into five major groups. The
clarity of this system recommends it for use here. In the following section each of the impacts
will be described, and its importance as a threat to each of the habitat types is evaluated as far
as information is available.
5.1 Chemical Changes
Because life is based upon the conversion of solar energy to chemical energy and the subsequent
use of that chemical energy, changes to the chemical regime of habitats profoundly affects the
species that live there.
Table 13: Toxic Chemicals & Nutrients in the Great Lakes
Lake
Superior
Michigan
Huron
Ontario
Erie
Connecting
Channels
Public Health Advisories
Lakewide
Restriction
(none)
Trout, Salmon
Trout
Trout, Salmon
Carp, Catfish
(none)
Local Restrictions
In all AOCs*; vary
Several warmwater fish
waterfowl
Catfish, Saginaw Bay,
Lake Trout, south of MI
Thumb
several warmwater fish
spp. in certain AOCs*
Walleye
many sport fish
St. Clair, Detroit River
Contaminant
Concentrations
Lowest
Highest in heavy
metals
second lowest
Highest for organic
chemicals, mercury
Low
Reflect upstream and
downstream lakes
Trophic Status
Oligotrophic
North-Oligotrophic South-
Mesotrophic; eutrophic in
degraded areas
Oligotrophic -Mesotrophic
Moderately eutrophic
Most eutrophic of the lakes
reflect upstream lakes
* - Areas of Concern, as designated by the U.S. and Canadian federal governments on the
recommendation of the International Joint Commission
Toxic Chemicals:
Through the processes of biomagnification and bioaccumulation, the impact of toxic chemicals
has been greatest on species at the top of the food chain, such as predatory birds, fish and
mammals. The highest concentrations have been observed in top predators in Oligotrophic
systems, where predators have few prey species, and those prey species in turn feed on a limited
number of other species. Because these systems are simple, the potential for biomagnifaction is
Aquatic Habitat and Wetlands - SOLEC Background Paper
37
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greater.
The example of the bald eagle illustrates the effects of toxic chemicals on birds of prey.
Historically the bald eagle nested around the shores of the entire Great Lakes system, and is
considered an excellent indicator of clean habitat. Bald eagles were extirpated from many of the
islands and shorelines of the Great Lakes in the 1950s and early 1960s, but have recently
returned to nest and produce young there (Postupalsky 1985). The primary reason for this
localized extirpation was egg shell thinning, caused by p,p'-DDE, the aerobic metabolite of DDT
(Colborn 1991). Prior to the widespread use of DDT after World War II, however, eagle
populations were already in decline. The loss of nesting habitat, changes in fish populations, and
persecution by humans were some of the reasons for their initial decline (Colborn 1991).
Although eagles have returned to the Great Lakes islands and shorelines, they still fail to produce
young at a level considered to be associated with a healthy population. Concentrations of p,p'-
DDE and PCBs within addled eggs and plasma of nestling eagles are sufficiently great to be of
concern (Bowerman et al. 1993; Sprunt et al. 1973).
Fish health and reproduction can also be affected by contaminants. Contaminated sediments in
the Detroit River may be toxic to fish eggs spawned there. Contaminants present in fish eggs
are believed to be limiting the survival of salmonids during their early life history (egg to swim-
up fry). Coho salmon in Lake Erie exhibit thyroid conditions and various syndromes of
reproductive dysfunction, including precocious sexual maturation, loss of secondary sexual
characteristics, low reproductive hormone levels, reduced egg fertility and high incidence of
embryo deformity and mortality (LEP, 1994).
Long-term effects on plants and herbivores are not well understood. Herbicides (e.g. Atrazine)
from cropland may be interfering with aquatic plant growth. Herbicides are present in the
wetlands and bays of Lake Erie at levels high enough to alter planktonic species composition and
inhibit photosynthesis of algal and rooted plant communities. Water soluble metals from
sediment pore water can reduce primary production by ultra and pico plankton (LEP, 1994),
While levels of DDT, PCBs and their metabolites will likely continue to decline, the effect of
the continuing discharge of other persistent toxic chemicals on the quality of the chemical regime
of habitats is not well understood. Toxic bioaccumulating chemicals affect the predators of food
webs based in aquatic habitats - open-lake, the inshore zone and tributaries. Thus toxic
chemicals are of great concern as they affect the viability of aquatic habitats.
Nutrients
The productivity of the meso- and oligotrophic portions of the Great Lakes are limited by the
availability of nutrients; nutrient additions lead to greater productivity. The result of nutrient
additions is to force out species that have adapted to low nutrient levels, in favor of those able
to better utilize the increased nutrient supply. In aquatic habitats, very high nutrient additions
lead to such an increase in productivity that the subsequent decay of the algae and other plants
depletes oxygen levels to the point where the other species can no longer survive.
Oxygen depletion as a result of high nutrient levels has been a major impairment of benthic
habitats in open-lake, the inshore zone and tributaries. Because nutrient additions have declined,
38
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anoxic conditions are no longer widespread. Currently, the main impact of nutrient additions
seems to be to reduce the habitat suitable to species that have adapted to low nutrient levels.
However, the reduction in nutrient levels has not always been followed by recovery of the
affected communities. Examples include the benthic community in the western basin of Lake
Erie, and aquatic plants in the shallow waters of Lake Ontario, neither of which have recovered
as expected (LEP, 1994 and Mathers, 1994).
Acidification
Acid deposition from the long-range transport of airborne pollutants has not been seen as a threat
to Great Lakes aquatic habitats because the geological buffering capacity seemed sufficient. It
has affected inland habitats, especially those on the Precambrian shield which had no buffering
capacity. Large scale efforts in the 1980s have reduced the discharge of acid gases to the
atmosphere. The long-term effects of present loads on Great Lakes habitats are not known.
Salinity
The storage and use of road salt introduces saline peaks primarily affecting inland tributaries and
wetlands. The extent of the stress on species in these habitats is not well understood.
Most of the acute effects of ongoing alterations to the chemical regime seem to be concentrated
on bird and fish predators at the top of the aquatic food chain. Some communities have not
recovered from major historical degradations. The long-term chronic effects of changes to the
chemical regime are not well understood, particularly with respect to the accumulation of
persistent toxic chemicals in habitats.
5.2 Hydrologic Changes
The hydrological regime of a habitat affects species composition and long-term community
dynamics in numerous ways. Not only are individual species sensitive to water depth and
current, and their short-term and seasonal fluctuations, but long-term fluctuations that disrupt
community succession are also critical to the maintenance of quality habitat in some cases.
Hydrologic changes which may be most significant to coastal wetlands (besides a total drainage
or fill) are the changes occurring from modified flow regimes due to development. Most urban
coastal wetlands experience much higher peak flows during storm events and lower base flows
at other times. Also, groundwater withdrawal may eliminate groundwater seeps and springs in
wetlands, altering the hydrologic regime further and affecting the water quality component of the
wetland (Mike Koutnik, Wisconsin Department of Natural Resources, pers. comm.).
Drainage
By far the most significant hydrological change has been the drainage of wetlands, primarily for
agriculture. Wetlands in all the habitat types - inland, shoreline and inshore - have been affected.
The overall loss is estimated at about 70%, but data on the comparative losses in each of the
above categories are not available. Because drainage represents a complete loss of the habitat,
Aquatic Habitat and Wetlands - SOLEC Background Paper 39
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this type of change is treated as a physical alteration in section 5.4.
Water level management
In wetlands, individual plant species and communities of species have affinities and physiological
adaptations for certain water-depth ranges. Changes in water level add a dynamic aspect to this
species/depth relationship. Water-level dynamics result in shifting mosaics of vegetation types.
In general, high water levels kill trees, shrubs, and other emergent vegetation, and low water
levels following these highs result in seed germination and growth of a multitude of species. The
magnitude of water-level fluctuations is of obvious importance to wetland vegetation. Frequency,
timing, and duration are also important characteristics of fluctuations. Water-level changes with
a seasonal frequency are likely to have different effects than fluctuations with a frequency of a
decade or longer; infrequent, unpredictable fluctuations will result in greater diversity than
annual fluctuations. Stable water levels with little fluctuation during the growing season will
likely result in stable shoreline plant communities, while unstable summer water levels will likely
result in variability in the vegetation.
High water levels (i.e. levels above the historical long-term mean) increase fish access to
spawning and nursery habitat in emergent vegetation and increase hemi-marsh habitat (half
vegetated, half open water) preferred by waterfowl. Detrital plant materials are also colonized
by invertebrates that are fed on by fish and waterfowl. Low water levels can jeopardize fish
spawning and reduce waterfowl nesting area; yet, they provide the opportunity for regeneration
of the plant communities that are the foundation of the habitat.
The ability of the vegetation to shift with the water levels depends on the slope of the substrate
above and below the wetland. Where alterations such as dredging or diking have taken place
around the wetlands, the wetland is eliminated during periods of low lake levels. Much more
common is the opposite - shoreline development that prevents a shoreward shift of vegetation
during periods of high lake levels. When the wetland vegetation can no longer shift rapidly in
response to fluctuations, the reestablishment of vegetation takes longer and the wetland is
impaired.
The presence of extensive shoreline development, often at the expense of habitat that can buffer
lake level fluctuations, has led to intense political pressure to stabilize and control water levels.
A study of the impact of major proposed water level regulation scenarios concludes that their
implementation would generally greatly reduce wetlands diversity. The lack of a long-term cyclic
pattern of peak summertime high lake levels with intermittent low summertime highs means that
species richness of the wetlands will likely decline as competitive dominants eliminate more and
more species (Wilcox et al. 1993). However fluctuations alone will not provide for wetland
vitality without a suitable gradient for vegetation shifts.
Loss of hydrologic connectivity
The viability of communities in many inshore habitats depend on water currents and flows that
bring nutrients, sediments and organic matter, and prevent the habitat from drying out. When
these currents are altered, as they can be by structures some distance removed from the actual
inshore habitat, the habitat is impaired. The construction of groins, breakwaters or alteration of
drainage into the inshore habitat are examples of this kind of activity. The extent of the
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impairment from such activity is not understood.
The lakeward diking of wetlands, often to improve habitat for waterfowl, cuts off migration
routes for spawning, juvenile and predator fishes. Summer and winter kill of fish is frequent in
diked marshes because the fish are unable to migrate out to avoid low dissolved oxygen levels
or temperature extremes.
Amount and fluctuation of tributary flow
The alteration of the amount and fluctuation of the flow regime in tributaries impairs the habitat
for spawning of lake fish and as permanent habitat for other species. The removal of the forest
and bankside vegetation tends to increase flooding and low water periods in the summer. Floods
flush streams enough to temporarily reduce concentrations of sulphates and chlorides. The
scouring action of floods often devastates plant life in or near streams (including overhanging
trees and shrubs); epilithic plants and phytoplankton may be dramatically reduced. Seasonal
floods can affect fish spawning; for example, eggs of fall-spawning brook trout were decimated
by winter floods, and the survival rate of spring-spawned rainbow trout fry increased due to
reduced competition from young brook trout. Such changes in species composition may endure
for years (Grizell 1976).
The construction of dams may control the worst effects of flooding, but introduces new
impairments to tributary habitat, including the physical alteration of habitat, sedimentation, and
changes to depth and current velocities. Again, the extent of habitat impairment through
hydrologic changes is not understood. The construction of dams has been severely limiting to
fish migration throughout the Great Lakes basin.
5.3 Physical Process Changes
Habitats are also defined by physical process and parameters, including temperature and
sedimentation.
Temperature changes have occurred primarily in tributaries through the removal of shading
bankside vegetation. The narrow temperature requirements of many fish are relatively well
documented. Increased temperature fluctuations have restricted the habitat of fish species.
Changes to the thermal regimes of the lakes are also expected. The decrease in nutrient levels
has increased water clarity, which in turn increases the depth of the epilimnion (Mayumder and
Taylor, in press). Major impacts from warm water outflows from electrical generating plants and
other sources have not been documented. The impact of deepwater cooling at the scale proposed
for Lake Ontario is currently thought to be small (Boyce et al., 1993).
Sedimentation is a major water pollutant in the Great Lakes Basin. Suspended solids carry
pollutants and reduce photosynthesis, oxygen content in water, and the survival rate of
invertebrate and fish eggs. They seriously interfere with the food-finding activities of many
valuable predator fish, and damage spawning grounds. Tributary and inshore habitats are
especially affected.
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In other cases, communities have adapted to the regular input of a certain level of sediments and
the nutrients they bring. When the sediment-carrying currents are halted or diverted, for instance
by groins, breakwaters, dikes and dams, habitats are also degraded.
5.4 Physical Alteration
Large-scale physical alteration and destruction has been the largest source of habitat loss in the
inland, shoreline, and inshore zones of the Great Lakes. While the conversion of natural habitats
to agricultural, urban and industrial uses has decreased, it has not ended. For wetlands, the most
recent estimate is 20,000 acres lost per year in the U.S. to a variety of developments, with an
estimated 70% of all wetlands in the Basin already lost, primarily to agricultural drainage. Data
for other habitat types are not available, but certain trends are evident:
- Urban lakefilling continues to affect inshore habitats. The rate has decreased, and the
current scale is probably relatively limited.
- Dredging and channelling for boat harbours has occurred in many estuaries, especially
on the lower lakes, representing a loss of significant inshore habitat (Limno-Tech, 1993).
- Deforestation for agriculture has been the largest source of loss of inland habitats.
Temporary losses for timber harvest continue on a relatively large scale, with concerns
raised about the loss in quality where old growth forests are being removed. Removal
of woodlots and larger second-growth forests continues on the urban fringe of growing
cities.
- Development of shoreline for recreation and residential uses continues, seemingly
unchecked. The rate of loss of shoreline habitat might be expected to be similar to that
of wetlands, as waterfront living continues to be in high demand. In contrast to the
infilling of wetlands, the level of concern is low.
The effect of physical alteration on species is straightforward: the habitat is eliminated. An
example from the Niagara River illustrates the effect. Two colonies of Black-crowned Night
Herons (representing 600 nests) were extirpated from Grand Island, while heron colonies (196
nests) persisted on downstream islands above Niagara Falls. The differentiating observation was
that Grand Island has experienced urban development and habitat loss, which did not occur on
the downstream islands supporting the latter heron colonies (Limno Tech, 1993).
Non-Consumptive Use Disturbance
A number of species require habitats removed from human disturbance. Wildlife is often
sensitive to disturbance at some distance, as the following examples illustrate:
- Mature bald eagles on Michigan's lower Peninsula were found to favor coniferous
perches farther from human disturbance than the predominantly deciduous perches of
immature eagles (Bowerman and Giesy, 1991).
- Migrating canvasback ducks stopping to rest and feed in the Detroit River do not
tolerate boat traffic.
Ambient noise levels and human and pet intrusions into habitats are also known to create stress
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for wildlife.
Some vegetation communities such as dunes have very low tolerance for the effects of trampling.
In dunes, the consequences are especially large because bare spots quickly erode from wind-
action.
5.5 Changes to Community Structure
Non-native species
Habitat can be degraded by forces other than physical destruction or contamination, notably the
introduction of foreign plant and animal species. Purple loosestrife, the zebra mussel, and others
have had a significant negative impact on aquatic and wetlands habitat quality, although the scope
and magnitude of these effects are not well understood.
For example, purple loosestrife displaces other plant species, and the species that depend on those
plants in wetlands around the basin. Carp have significantly affected inshore habitats in some
areas through their resuspension of the substrate fine material in the water column. Higher
turbidity prevents the establishment of submergent vegetation and reduces the feeding efficiency
of ambush and sight feeders such as pike and bass (LEP, 1994).
Zebra mussels reduce the incubation and hatching success of lake trout and whitefish eggs (Ken
Muth pers. comm.). In controlled laboratory studies at the Sandusky Biological Station in Ohio,
egg survival and hatching of lake trout was significantly lower in test aquaria containing zebra
mussels than in aquaria without mussels. Dissolved oxygen declined and ammonia increased in
tanks with zebra mussels, but probably not to lethal levels if water temperatures were cool during
incubation. In the lake, fish deposit eggs when water temperatures are warmer, and the
metabolism of zebra mussels may increase and alter dissolved oxygen and ammonium
concentrations sufficiently to cause egg mortality. There is a possibility that zebra mussels could
negatively impact spawning success of these two coldwater fish species even though zebra
mussels have evidently caused Lake Erie to become more oligotrophic, which should favor these
two species.
In Lake Erie, colonization by zebra mussels and quagga mussels has resulted in the mass
extinction of native Unionidae clams (Schloesser and Nalepa in press). Changes in the
composition and standing crop of profundal benthos have been linked to the colonization of such
substrates by quagga mussels, and the interception of detrital material as it settles.
Further, the Lake Erie stocks of the eastern smelt, the eastern and central basin yellow perch and
white perch appear to be declining. These changes are consistent with an ecological role of zebra
and quagga mussels intercepting organic detritus that would otherwise have supported secondary
production by chironomids, mayflies and amphipods in soft littoral and profundal substrates
(LEP, 1994).
To better define the nature and magnitude of the threat posed by the ruffe in the Great Lakes,
scientists from the U.S. National Biological Survey-Great Lakes Centre (Tom Edsall pers. comm.)
Aquatic Habitat and Wetlands - SOLEC Background Paper 43
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studied the thermally suitable habitats in the Great Lakes that the ruffe might colonize and
identified fish communities that might be most affected bye the ruffe if it spreads into these
habitats.
Ruffe grew fastest in laboratory studies at 22 degrees Centigrade, which indicates that it is a
coolwater fish as are native Great Lakes percids such as walleye, sauger, and yellow perch.
Based on recent estimates of thermally suitable habitat area in the Great Lakes for walleye, 6.5
million hectares should suit the ruffe. Lake Erie, the shallowest and warmest Great Lake had
58% of the total. Lake Huron had 21%, mostly in the North Channel, Georgian Bay, and
Saginaw Bay; Lake Michigan and Green Bay had 12%; Lake Ontario, 7%; and Lake Superior,
the deepest and coldest lake, 2%.
The potential effects of large populations of ruffe on the fish communities of Lakes Erie, Huron
and Michigan are unknown. If ruffe were to become as abundant in all the thermally suitable
habitat as in the St. Louis estuary of Lake Superior, it would be a major problem for the Great
Lakes fishery. A decline in yellow perch abundance similar to that seen in the St. Louis River
estuary would seriously impact the fishery for yellow perch which is presently valued at US $101
million in Lake Erie alone.
Fish Stocking
Community structure needs to be addressed along with habitat considerations. Stocking of fish
predators may alter the predator-prey balance in pelagic communities and thus affect water
quality. The necessity for addressing the compatibility of water quality (nutrient abatement)
objectives and fishery management (predator stocking) strategies is being recognized and is being
integrated into ecosystem objectives for various lakes (Bertram and Reynoldson 1992; Superior
Work Group 1993).
Other changes to the biological structure of the habitats has resulted from over harvesting of fish
and birds which have led to shifts in species dominance and even extinction.
5.6 Impact Analysis
Given the variety and extent of impacts on habitats in the Basin, some effort to evaluate the
relative degree of stress posed by each type of impact is needed. Busch et al (1993), set out a
system for assessing the degradation of specific habitats based on measurable criteria. This
system requires a detailed measuring regime, both of the habitat being studied and nearby non-
degraded habitats. This system has not been implemented to date. In the absence of systematic
basin-wide monitoring of relative impacts, the Nature Conservancy (1994) has used a simple
ranking system based on professional judgement. Results of this evaluation showed greatest
stress on biodiversity resulting from habitat destruction, alteration of lake levels and stream flows,
and competition from non-native species. Unlike the addition of toxic chemicals and nutrients,
whose effects were given a medium score, the physical alterations were seen to be generally
irreversible. In establishing priorities to conserve and protect habitat, further analysis and
consensus on the relative threat posed by different impacts seems desirable.
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6.0 Existing Initiatives
Numerous laws and initiatives in both Canada and the U.S. are designed to protect and restore
Great Lakes habitat. The ongoing loss and impairment of habitat suggests they have not yet been
successful in reversing the trend of the last two centuries. Whether or not they have slowed the
rate of degradation cannot be ascertained as the data are not available or inadequate to accurately
determine basin wide trends.
6.1 Research and Information Gathering
Systematic inventories and assessments of habitats on a basin-wide level are not yet being carried
out. Bowerman's (1993) study of bald eagle nesting habitat stands out as an isolated exception.
Most of the habitat assessment effort to date has focused on wetlands. However, despite ranking
among the most studied wetlands in North America, the Basin's wetlands have never been
inventoried completely, and only Ducks Unlimited has routinely studied wetlands in both the
United States and Canada (Whillans et al, 1992).
Binational Initiatives
The International Tracking System standardizes reporting of wetland restoration, protection, and
other data in the U.S. and Canada. Data are available for the fiscal years 1992 and 1993
(October 1, 1991 to September 30, 1993).
Canadian Initiatives
Environment Canada, often in cooperation with other agencies and groups, is gathering habitat
related information through a number of programs. An Environmental Sensitivity Atlas for Lake
Superior's Canadian Shoreline has been complete for over a year. A draft Environmental
Sensitivity Atlas of Lake Huron's Canadian Shoreline has just been completed with the Canadian
Coast Guard. A recent Catalogue of Wetland Inventories and Databases confirmed the need for
a computerized, comprehensive, current wetland inventory at a uniform scale that could be used
to determine wetland area, measure target achievement and monitor change. Historical vegetation
community mapping is occurring in a several significant wetlands. Several programs exist to
monitor various bird populations, and a program to monitor contaminant levels and health of
several indicator species is being expanded.
U.S. Initiatives
The U.S. Environmental Protection Agency has included coastal wetlands as a resource class in
its Environmental Monitoring and Assessment Program (EMAP) for the Great Lakes. The EPA
has begun to plan pilot and demonstration studies to determine the best way to monitor the
condition of wetlands on each of the Great Lakes.
To provide a consistent national database on wetlands, the Nationals Wetlands Inventory (NWI)
is classifying and mapping all wetlands in the U.S. from aerial photographs. The information
is also being entered into three database systems that will comprise the NWI Geographic
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Information System (GIS) and allow computer access to the data. The NWI also prepares
wetland trend studies and special reports to Congress.
The digitized NWI database would facilitate ecosystem management, including environmental
impact assessment and monitoring, information retrieval, quantitative and qualitative analysis,
contaminant studies, fisheries and wildlife studies, restoration, enhancement and protection
planning and others. The North American Waterfowl Management Plan (see Section 6.2), in
particular would benefit from an NWI digital database (Santos, pers. communication).
The status (February 1994) of NWI mapping is shown in Figure 2. Mapping of some areas of
the Great Lakes is complete, but information for the entire U.S. portion of the basin is not
expected until after March 1995 (Tom Dahl, personal communication). Digitization of the NWI,
lags behind the mapping, with all of Michigan, northern Ohio, and part of New York still to be
converted. Wisconsin's wetland database may not be compatible with NWI (Santos, pers.
communication).
No comparable program to map other habitat types has been conceived in either country.
Classification Systems
One obstacle to basin-wide inventories is the lack of consensus on an ecosystem wide habitat
classification system. In the U.S., the NWI is using the system developed by Cowardin et al
(1979) for mapping wetlands. In Ontario, the Ministry of Natural Resources system of
evaluating wetlands south of the Precambrian shield based on their hydrological, social, biological
and special feature values has seen the most extensive application (Whillans et al, 1992). Data
collected under these two systems are not compatible. Busch and Sly (1992) and an international
team that included many Canadian and U.S. participants reported on the Aquatic Habitat
Classification (AHC) System to facilitate mapping of all types of aquatic habitat. The AHC uses
the NWI system and expands it to provide more detailed application to open water and tributary
habitats and should be amenable to incorporation in computer database systems (Busch et al,
1993). It is not clear whether data gathered under this system are compatible with the Canadian
system, nor has a consensus on the basin-wide use of the AHC developed.
The AHC considers upland areas only in so far as they provide habitat for wildlife populations
that rely on the lake for survival (Busch et al, 1993). Compatibility of any basin-wide system
to map aquatic habitat, with terrestrial classification systems may also require consideration.
6.2 Habitat Protection
Initiatives
The North American Waterfowl Management Plan (Plan) is a joint Canadian - U.S. - Mexican
effort and offers many opportunities for wetland protection and enhancement in the Great Lakes
basin. The Plan has among its goals to protect approximately 407,000 acres of critical aquatic
and associated upland habitat, enhance approximately 135,000 acres of wetlands, and create
approximately 19,000 acres of wetlands. Ongoing losses and alteration of habitat were the
reasons for setting these goals. Program implementation has evolved to restoring historical
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hydrology and vegetation as close as possible. In Ontario, the Plan is implemented through the
Eastern Habitat Joint Venture, a partnership of a number of organizations. The Great Lakes
ecological zone has been identified as the most significant, and initiatives are under way to
secure, preserve and restore wetlands using a broad variety of instruments.
In 1981, Canada became a signatory to the RAMSAR Convention on Wetland of International
Importance, Especially as Waterfowl Habitat, and to date thirty wetlands, including three on the
Great Lakes, have been identified and protected under legislation.
Canada and the United States have developed a Binational Program to Restore and Protect the
Lake Superior Basin. This program focuses on the Lake Superior Ecosystem including the water,
air, land and the people of the basin. Of greatest importance to habitat protection are its
programs for Special Designations and Habitat in the Basin.
United States
Within the United States, wetlands are managed through a mixture of federal, state and local
initiatives, with public input from citizens and interest groups. The federal government's primary
tool for protecting wetlands is Section 404 of the Clean Water Act. In accordance with Section
404, the U.S. Army Corps of Engineers (Corps) and the Environmental Protection Agency (EPA)
regulate the discharge of dredged or fill materials in "all waters of the United States". Under
Section 404 the Corps considers the advice of EPA, the U.S. Fish and Wildlife Service (Service),
the National Marine Fisheries Service, other agencies and the public when deciding whether to
issue or deny a permit.
One state in the Great Lakes basin (Michigan) has assumed administration of the Section 404
program. Most, but not all, wetland permit actions are handled by the Department of Natural
Resources in Michigan. The other states in the basin also have wetland management laws that
afford varying levels of protection to wetlands. Each state operates independently according to
its own laws.
Federal agencies are obliged to comply with the Federal wetlands Executive Order 11990 and
Federal Floodplains Executive Order 11988, which direct that wetland and floodplain impacts
should be avoided or minimized to the extent possible. The Order requires specific procedures
for agency activities related to: 1) acquiring, managing and disposing of federal lands and
facilities; 2) providing federally undertaken, financed or assisted construction and improvements;
and, 3) conducting federal activities related to land use.
In 1990 the U.S. Environmental Protection Agency released National Guidance on Water Quality
Standards for Wetlands (Environmental Protection Agency 1990a). In this document, EPA
regional officials and State Water Quality Managers are required to (1) include wetlands in the
definition of "State waters," (2) establish beneficial uses for wetlands, (3) adopt existing
narrative and numeric criteria for wetlands, and (4) adopt narrative biological criteria for
wetlands, and (5) apply anti-degradation policies to wetlands.
The conservation provisions of the 1985 Food Security Act (Farm Bill) and the 1990 Food,
Agriculture, Conservation and Trade Act (FACT Act) have continued to encourage the
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preservation of a vast acreage of agricultural wetlands and highly credible croplands. The
Swampbuster provision eliminates price supports for individuals who convert wetlands to produce
agricultural commodities. In addition, the eight states at least partially within the Great Lakes
basin have enrolled a total of over 4,8 million acres in the first twelve Conservation Reserve
Program (CRP) signup periods, 13.2% of the national total. Average erosion reduction achieved
in the acres signed up in the eight Great Lakes states ranged from 11.0 to 19.9 tons of topsoil
per acre over the first ten signups.
Programs and partnerships are underway by the United States Forest Service and several other
U.S. Department of Agriculture Agencies. State and local governments are active in habitat
initiatives. Within Great Lakes Basin States there are Natural Heritage programs, now also in
Canada, although they are focused on natural communities and species more than "habitat."
Notable programs in some states include Michigan's Dune Protection Act and Wisconsin's
shoreline zoning program, and local watershed councils. Private sector initiatives such as the
Nature Conservancy's, Ducks Unlimited and Trout Unlimited are vital to habitat in the Great
Lakes Basin. But these are only a partial listing of the important initiatives underway, and more
details can be found in The Nature Conservancy (1994) or by contacting the Great Lakes
Commission, or by consulting Donahue (1986).
Canada
Environment Canada recently coordinated the development of the Strategic Plan for the Wetlands
of the Great Lakes Basin, which aims to protect existing wetlands and achieve an overall increase
in the area and function of Great Lakes Wetlands by the year 2020. The priority of the first five
year Action Plan is the coastal wetlands of the lower Great Lakes. The Plan was developed with
a number of non-governmental organizations and federal and provincial agencies (Patterson,
1994).
Programs aimed at making agriculture more sustainable and compatible with the preservation of
wildlife habitat through demonstration, education and research were launched in 1992 and 1993.
Another program will provide artificial nesting habitat for bald eagle, osprey and perhaps
peregrine falcons (Patterson, 1994).
In Ontario, the most significant mechanism protecting wetlands from impacts resulting from land
development is the Planning Act. Under the Act, the Ontario Ministry of Natural Resources can
use opportunities in the municipal planning process to ensure development is consistent with its
mandate for management of natural resources. In 1992, the Wetlands Policy Statement under
Section 3 of the Planning Act was announced. The policy prohibits municipalities from
approving development in "provincially significant wetlands" (LEP, 1994).
Nevertheless, the cumulative loss of coastal wetland continues for several reasons:
- The policy statement provides only indirect protection to wetlands that are not
provincially significant (Class 4-7).
- Municipal controls under the Planning Act are only as effective as municipal intent to
enforce their implementation. This intent may not always be strong - particularly in
difficult economic times.
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- A legislative equivalent to the Fisheries Act does not exist to provide absolute protection
of wetlands. Penalties for wetland destruction are generally small and not a deterrent.
- The Planning Act cannot prohibit landowners from altering the shape of their land prior
to the planning process (e.g. a fanner filling in a wetland on his property or a developer
clearing and grading a site prior to submitting a draft plan of subdivision of a marina
development proposal).
Other Ontario acts and regulations provide the authority to control and restrict discharges and the
management of waste. Provincial policies establish that water must be satisfactory for aquatic
life.
The Fisheries Act (Canada) provides the best protection for aquatic habitat in Canada, provided
that such habitat meets the definition of "fish habitat" for the purposes of this Act. It ultimately
prevents any work, without permission, that would cause harmful alteration, disruption, or
destruction of fish habitat. This Act also can protect wetlands where fish habitat occurs. Where
permission is given to alter habitat, the proponent is required to repair, replace, mitigate and
sometimes compensate for these alterations or losses.
6.3 Restoration
Wetlands and aquatic habitat restoration is still a rather young science, with long-term rewards
unclear. A fair amount of restoration is being attempted around the Great Lakes system, and
while its overall effectiveness in terms of quality is uncertain, it holds a clear potential in terms
of offsetting historically lost or altered acreage.
Habitat loss, particularly in the case of wetlands, is in many cases a continuum - a matter of
degrees of degradation and/or function loss, rather than an "all-or-nothing" proposition. This
means that restoration of function is also not necessarily a simple "yes/no" question: restoration
can be partial or incremental as resources or conflicting uses allow. Restoration and protection
of partially degraded sites is therefore an important goal; complete re-creation of all natural
values is not the only worthwhile goal.
The Great Lakes CleanUp Fund supports habitat enhancement, rehabilitation and recreation in
Areas of Concern as well as in other significant wetlands such as the Oshawa Second Marsh, the
Dunnville Marshes, the Long Point Wetlands and the Lake St. Clair Wetlands.
A search of the 1992 and 1993 data of the International Tracking System found that 4984.27
acres had been restored and 5874.6 acres protected in U.S. counties which are at least partly in
the Great Lakes Basin. The total combined acreage for fiscal years 1992 and 1993 was therefore
10,858.87 acres. Comparing this to the previously quoted estimate of 20,000 acres lost per year
basin-wide, both countries appear to be falling well short of just keeping the wetland habitat base
they have. Data on the extent and success of Canadian habitat restoration initiatives were not
available.
The performance of Basin wetland mitigation and creation programs was addressed by several
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papers presented at the International Symposium on Wetlands of the Great Lakes (Fishbein 1990;
Jahn 1990; Prokes 1990 and others). None of the authors took a basin-wide approach, but rather
looked at case study areas ranging from a single permit to multiple-state regions (some states of
which are outside the Great Lakes basin). Since that symposium, the U.S. Fish and Wildlife
Service has implemented a number of recommendations, including changing restoration efforts
to focus more on multi-species, multi-use goals, as opposed to simply aiming for, say waterfowl
restoration.
Aquatic habitat restoration efforts have so far not been widespread on the Lakes, nor have many
results been well documented or tested, so its potential is unclear.
In a study of mitigation permits in southeast Michigan from 1984 to 1989, Prokes (1990) found
the ratio of acres lost to acres created rose from 0.44 to 1.57. While this study does show
improvements in mitigation permits, the overall role of mitigation remains limited because more
than 99% of all permits issued to degrade wetlands by the Michigan Department of Natural
Resources since it started its wetland regulatory program do not require any mitigation
whatsoever (Cwikiel, pers. communication).
Prokes (1990) found that although mitigation permits from 1985 to 1987 were generally
inconsistently prepared and exhibited high variability, permits from 1988 and 1989 showed
significant improvement with more detailed and sophisticated mitigation design and follow-up
management requirements included as permit conditions. However, because tracking was not
carried out combined with enforcement of mitigation requirements to ensure success, too many
projects remain incomplete (although the impacts have already occurred), were poorly
constructed, or were not completed in accordance with permit specifications. For example,
although a permit may have specified the creation of 3 acres of wetland, because of poor
construction design or non-adherence to the permit conditions, less wetland may actually have
been created than proposed. In addition, most mitigation projects completed in 1985 and 1986
did not appear to be developing into functionally valuable wetland habitats. Consequently,
although no net loss was theoretically achieved as calculated by the loss and creation specified
in the mitigation permits, in reality we are probably not only seeing a net loss of wetland habitat
acre for acre, but replacement with wetlands that lack the functional values of the original habitat
(Prokes, 1990).
Some habitat restoration programs use the habitat requirements of a specific species as their point
of departure. Federal and State plans have been formulated for rehabilitating the eastern
population of canvasback ducks and their habitat. The Federal plans identify pollution and
limited food resources as primary causes of dwindling migration habitat and reduced numbers
of birds (USDI 1986), particularly industrial pollution and the loss of wild celery beds in the
Detroit River (Getting 1985). The State plan predicts slow improvement of canvasback habitat
in the Detroit River, if pollution controls are continued (Martz et al. 1976). The overall strategy
of these plans is to provide adequate migration habitat across the Great Lakes states, rather than
crowding fall-migrating canvasbacks into the few pools on the upper Mississippi River where
suitable habitat is still available for them.
Jahn (1990) provides a detailed account of the mitigation process as it applied to a single project
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in Onondaga County, New York, Her conclusions provide poignant testimony to both the state
of expectations and reality in mitigating habitat loss within the Great Lakes basin:
"Costs are incurred when expectations and reality in a wetland creation project clash.
There is a cost to the environment from continued loss of habitat. At this site, nearly
three years,have passed in which the mitigation wetlands have not been present to
compensate for the 1.5 acres of wetland lost to construction. There is a cost to the
permittee from the additional work which must be undertaken to satisfy the mitigation
requirements of the permit. There is a cost to the resource agency in the form of
additional staff review that is required. Ultimately, we as society incur the total cost for
wetland creation projects which fail. These costs can be minimized by careful design
focused on hydrology, and by an increased awareness of the responsibilities of all parties
involved in the permit process, especially the permittee and the resource agencies. We
are all responsible to each other for the wise use of our resources."
6.4 Authorities
Various laws, statutes, policies and agreements are utilized to protect and conserve wetlands and
aquatic habitats (Kavetsky 1990; U.S. Department of the Interior and Environment Canada 1986).
Besides those highlighted previously in the text, numerous other authorities at the Federal,
Provincial, State and local level provide opportunities for protecting and restoring wetlands and
habitat in the Great Lakes. These opportunities are obviously not being fully used, since many
have been available for decades while the net loss of habitat has continued. A partial list
includes authorities for constructing habitat restoration, enhancement and creation projects;
planning federally funded, permitted, authorized, or managed public works or other projects;
recovery actions and consultations; and rehabilitation and management of wild animals and their
habitat.
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Authority
Legal Citation, if known
Species or target habitat
International/Binational
North American Waterfowl
Management Plan
Migratory Bird Convention
Great Lakes Water Quality
Agreement
Strategic Plan for Great
Lakes Fisheries Management
RAMSAR Convention on
Wetlands of International
Importance
Conservation of waterfowl
habitat
Migratory birds
Wetland preservation
Binational management for
fish species and their habitats
Important wetlands identified
and protected through
legislation
United States
National Wildlife Refuge
System Administration Act
Fish and Wildlife
Coordination Act
Great Lakes Fisheries Act
Endangered Species Act
Migratory Bird Treaty Act
and Migratory Bird
Conservation Act
Emergency Wetlands
Resources Act
Fish and wildlife Act of
1956, as amended
Comprehensive
Environmental Response,
Compensation and Liability
Act of 1980 (CERCLA)
Airport and Airway
Development Act
16 USC 668dd-668jj
16 USC 661-667e
16USC931-939c
16 USC 1531-1543
16 USC 701-7181
P.L. 99-645
16 USC 742a-742j
43CFR 11
49 USC 1701-1742; 84 Stat.
219
fish and wildlife on all U.S.
Fish and Wildlife Service
lands
fish and wildlife, must be a
Federal project
fish habitat, sea lamprey
control
any listed or candidate
species habitat
migratory birds
wetlands
fishery and wildlife resources
construct habitat projects to
restore or replace injured
resources
habitat
52
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Anadromous Fish
Conservation Act
16 USC 757a-757g; 79 Stat.
1125
anadromous fishery resources
Bankhead-Jones Farm Tenant
Act
7 USC 1000, 1006, 1010-
1012; 50 Stat. 522
"...land conservation and
utilization in order to correct
maladjustments in land
use-
Estuary Protection Act
16 USC 1221-1226; 82 Stat.
625
pre-acquisition study and
inventory of estuaries of the
United States, including land
and water of the Great Lakes
Federal Power Act
16 USC 791a-825r; 41 Stat.
1063
fish and wildlife resources
Lacey Act of 1900
16 USC 701, 702; 31 Stat.
187, 32 Stat. 285
fish and wildlife, also
injurious species controls
Sikes Act
USC 670a-670o; 74 Stat.
1052
fish and wildlife, esp.
military and tribal lands
Watershed Protection and
Flood Prevention Act
16 USC 1001-1009; 33 USC
70Ib; 68 Stat. 666
fish and wildlife
Federal Water Project
Recreation Act
16 USC 4601-21
facilities for fish and wildlife
at all reservoirs under the
control of the Secretary of
Interior except those within
National Wildlife Refuges
Federal Aid in Sport Fish
Restoration Act of 1950
(Dingell-Johnson) and
(Wallop-Breaux)
16 USC 777-777k
funding to States for
management of sport fish
(land acquisition, research,
development and
management projects)
Wildlife Restoration Act
(Pittman-Robertson)
16 USC 669-669i
funding to States for land or
water adaptable as feeding,
resting, or breeding places
for wildlife
Coastal Zone Management
Act
16 USC 1451-1464
assist State programs to
protect, develop and enhance
coastal resources
Federal Water Pollution
Control Act Amendments
33 USC 1251-1365,1281-
1292,1311-1328, 1342-1345,
1361-1376
water quality which provides
for protection of fish,
shellfish, and wildlife;
Bay/Estuary programs
Aquatic Habitat and Wetlands - SOLEC Background Paper
53
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Nonindigenous Aquatic
Nuisance Prevention and
Control Act of 1990
North American Wetlands
Conservation Act of 1989
Great Lakes Fish and
Wildlife Restoration Act of
1990
16 USC 4701-4741
16 USC 4401-4412
16 USC 941a-941g
unintentional introductions of
nonindigenous aquatic
species
wetland ecosystems and other
habitats for migratory birds
and other fish and wildlife
fish and wildlife resources
and their habitats of the
Great Lakes basin
Canada
Migratory Bird Convention
Act
Canada Wildlife Act
Federal Policy of Wetland
Conservation
Federal Fisheries Act
Ontario Planning Act
Ontario Public Lands Act
Ontario Lakes and Rivers
Improvement Act
Ontario Environmental
Assessment Act
Ontario Wetlands policy
statement
Protects migratory birds and
habitat
Protects fish habitat
Allows Min, of Natural
Resources input into
municipal planning
requires permit for work on
Crown Land
requires work permit if
project will affect water
movement in streams either
on public or private lands
requires environmental
assessment for government
works and selected private
proposals
Under Planning Act;
municipalities must have
regard for policy in all land
use decisions
Some solutions to the various environmental stresses that cause losses and alteration of wetlands
have to be implemented at the lowest level of government. Advice, advocacy, data, education,
funding and lobbying offered by any group to local clientele may facilitate a solution. Successful
local management ordinances are often those with: 1) an underpinning of sound technical data,
a comprehensive plan, and evenhanded administration; and 2) a partnership between the
54
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Federal/State/Province, the local community, and its citizens in developing and implementing the
ordinance.
Aquatic Habitat and Wetlands - SOLEC Background Paper 55
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7.0 Management Implications
Conservation actions aimed at protecting diversity, productivity and function of the Great Lakes
Basin must strategically address the key sources of stress. First efforts need to focus on
protecting habitats that are most important to the basin's ecosystem. They must also concentrate
on reducing key sources of stress, and do so sustainably in a variety of socioeconomic settings
that represent the diversity of challenges present in the basin. Integral to all actions is the need
to gain a better understanding of what key species and communities need to survive.
Four major types of strategic activity are recommended to protect the habitats of the basin:
1) Developing strategically-coordinated, locally-based and driven projects that collectively address
the most significant systems and stresses;
2) Improving the basic and applied science necessary for habitat conservation;
3) Increasing awareness of the basin's ecosystem and of methods to protect it;
4) Increasing the support of regional institutions, both governmental and private, for the
protection of habitats.
Among the reasons for ongoing wetland losses are varying levels of commitment to wetlands
protection, inconsistent administration of programs, and slow development of protection policy.
Despite heightened public awareness, there are still many who view a wetland as a future
agricultural field, shopping mall, or housing development. There are hopeful signs, however
(Functional Group 2 1989). Actions needed include:
1. Protection of remaining wetlands should be encouraged by restricting shoreline
development and managing for production of fish and wildlife, where this is compatible
with the wetland's historic and current functional values. "Attractive nuisances" for fish
and wildlife contamination should be avoided.
2. The restoration of wetlands where they once existed or new wetlands on sites where there
is a high likelihood of success should be encouraged in and along the Lakes,
Interconnecting channels and tributaries.
3. Boaters should be discouraged from entering areas where large numbers of migratory
waterfowl feed and rest in the spring and fall.
4. No new construction of closed dike systems that totally isolate wetlands from the lake and
reduce wetland functions.
A wide variety of management decisions have widespread, often unintended effects on wetlands
Aquatic Habitat and Wetlands - SOLEC Background Paper 57
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and coastal habitat: nutrient levels and inputs, species introductions, water level controls, etc. as
previously mentioned. What is believed to be needed to better protect and restore wetlands and
other natural habitat is probably not more laws, but rather better implementation and enforcement
of existing authorities. For example, the Great Lakes Water Quality Agreement commits the
federal governments to efforts to protect habitat and wetlands. A previous section of this chapter
lists more than 20 authorities that can serve as tools to better protect, enhance, restore and create
habitat throughout the Great Lakes basin, provided the resources are committed to this important
effort.
Use of the Great Lakes, their interconnecting channels, and tributaries for the dilution and
disposal of liquid and solid wastes is in clear conflict with the basic biological processes in these
waters, including the production of valuable fish and wildlife resources. However, many
conflicts between uses should be resolved by implementing the following recommendations.
1. Sewage treatment plants discharging into the Lakes, interconnecting channels, and their
tributaries should be upgraded to tertiary effluent level for organic matter and heavy
metals, and operated at design standards.
2. Combined sewer overflows and industrial discharges to the Lakes, interconnecting
channels, and their tributaries should be reduced and their toxic substances content should
be more adequately monitored.
3, New connections to sewers that have insufficient storm water capacity should be delayed
until combined sewer overflows are eliminated.
4. Contaminated sediments should be removed from catch basins and sewer pipes that
discharge into the Lakes, interconnecting channels and their tributaries.
5. Heavily polluted sediments should be dredged (with no overflow), decontaminated, and
disposed of in acceptably designed, managed and monitored confined disposal sites,
preferably on land.
6. Confined disposal facilities should be protected and managed for the benefit of fish and
wildlife, but only if studies show such sites are not toxic to plants and animals.
7. Adequate containment safeguards around hazardous substance storage and handling
facilities on shore should be installed and maintained to prevent oil and contaminant spills
into the Lakes, Interconnecting channels and tributaries, especially during winter.
8. A public education and involvement campaign should be launched to promote the Lakes,
interconnecting channels, and their tributaries as valuable natural resources, discourage
pollution of them, and generate support for planned pollution control efforts. The Lake
Superior Binational Program and many other efforts provide good examples of such
campaigns.
58
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The present state of knowledge about habitats, their extent and quality, and the stresses that affect
them is not adequate to set priorities for protection and restoration, nor in many cases, to decide
which action to take to best protect and restore habitat. There are many research needs, too
numerous to list here, that must be addressed.
Many initiatives to protect and restore the Great Lakes ecosystem are planned and under way.
Integrating habitat considerations into these initiatives will increase their effectiveness. Habitat
programs should be involved in developing:
Contaminated sediments remediation;
Great Lakes confined disposal facilities;
Remedial Action Plans;
Lakewide Management Plans;
Water Quality Standards;
Watershed Plans;
Risk assessment Modelling;
Spill responses;
Non-indigenous species strategies;
Landscape planning;
Educational tools on ecosystem health;
Lake Superior Binational program;
Fish community objectives; and
Fish population restoration projects.
Conclusion
Clearly the health of habitat and wetlands is a major concern in the Great Lakes Basin. A
number of programs, laws and policies already exist to enhance habitats in the Great Lakes
Basin. What is needed to better protect and restore wetlands and other aquatic habitats is
probably not more laws, but rather stronger will to conserve habitats, implementation and
enforcement of existing laws, regulations and policies. Coupled with this need for improved
implementation and policy is the need for a strategic approach to habitat protection and
restoration, making full use of all levels of partnerships.
Aquatic Habitat and Wetlands - SOLEC Background Paper 59
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8.0 References
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Atkinson, J. 1994. Contribution to the SOLEC Habitats and Wetlands Working Paper: Connecting Channels.
(unpublished).
Balesic, H. 1979. "Literature Review of the Physical Characteristics and Fishes of the Northern Nearshore Zone of
Lake Ontario," Ontario Hydro Research Division Report. No. 79-165-K. Toronto: Ontario Hydro.
Bedford, B. L. 1990. Increasing the scale of analysis: The challenge of Cumulative Impact Assessment for Great
Lakes Wetlands. Proceedings: International Symposium on Wetlands of the Great Lakes, Niagara Falls, NY pp. 186-
195.
Bellrose, F. C., and R. D. Crompton. 1970. Migrational behavior of mallards and black ducks as determined from
banding. 111. Nat. Hist. Surv. Bull. 30(3): 167-334.
Bertram, P. E. and T. B. Reynoldson. 1992, Developing ecosystem objectives for the Great Lakes: policy, progress
and public participation. Journal of Aquatic Ecosystem Health. 1:89-95.
Botts, L. and B. Krushelnicki. (1987). The Great Lakes: an Environmental Atlas and Resource Book. United States
Environmental Protection Agency and Environment Canada. 44 pp.
Bowerman, W. W., IV. 1993. Identification of potential bald eagle nesting habitat along the Great Lakes. Chapter
4 hi Regulation of bald eagle (Haliaeetus leucocephalus) productivity in the Great Lakes Basin: An ecological and
toxicological approach. PhD Dissertation, Michigan State University pp. 75-115.
Bowerman, W. W., and J. P. Geisy, Jr. 1991. Ecology of bald eagles on the Au Sable, Manistee, and Muskegon
Rivers. Final report to Consumers Power Company (WP NO. 412E322) Hydroelectric Project Environmental
Studies: Bald eagle Studies. Michigan State University Department of Fisheries and Wildlife, Pesticide Research
Centre, Institute for Environmental Toxicology, East Lansing.
Bowerman, W. W., D. A. Best, J. P. Geisy, T. J. Kubiak, and J.K. Sikarskie. 1993. The influence of environmental
contaminants on bald eagle populations in the Laurentian Great Lakes, North America. IV World Conf. on Birds of
Prey, Berlin.
Boyce, P.M., P.P. Hamilton, L.D. Harvey, W.M. Schertzer and R.C. McCrimmon. 1993. Response of the Thermal
Structure of Lake Ontario, 1750-2050. (Occasional Paper 90-8) Buffalo, N.Y.: State University of New York).
Bridger, K.C. and D.A. Oster. 1981. Lake Ontario Tactical Fisheries Plan. Ontario Ministry of Natural Resources.
Busch, W.-D., M. Lazeration, M. Smith, and M. Scharf. 1993. 1992 Inventory of Lake Ontario Aquatic Habitat
Information. U.S. Fish and Wildlife Service, Lower Great Lakes Fishery Resources Office, Amherst, New York.
Busiahn, Tom. 1994. Personal communication.
Busiahn, T.R. (ed,). 1990. Fish Community Objectives for Lake Superior. Great Lakes Fishery Commission Special
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Christie, WJ. 1972. "Lake Ontario: Effects of Exploitation, Introductions, and Eutrophication on the Salmonid
Community," Jour. Fish. Res. Board Canada. Vol. 29 No.6: 913-929.
Colborn, T. 1991, Epidemiology of Great Lakes bald eagles. J, Toxicol. Environ. Health 33:395-453.
Cowardin, L.M., V. Carter, F.C. Golet, E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of
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Wildlife Service, Washington, D.C. 21 pp.
Donahue, M. J. 1986. Institutional arrangements for Great Lakes management: past practices and future alternatives.
Doctoral dissertation, University of Michigan, Ann Arbor, Michigan. 551 pp.
Edsall, T.A., E.F. Stoermer and J.P. Kociolek. 1991. "Periphyton accumulation at Remote Reefs and Shoals in Lake
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Edwards, C. J., Hudson, P. L., Duffy, W. G., Nepszy, S, J., McNabb, C. D. , Haas, R. C., Liston, C. R., Manny, B.
A., and Busch, W. N. 1989. Hydrological, morphometrical, and biological characteristics of the connecting rivers
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Fishbein, N. 1990. Restoring Agricultural Wetlands: An Analysis of the U.S. Fish and Wildlife Service Wetland
Restoration Program. Proceedings: International Symposium on Wetlands of the Great Lakes, Niagara Falls, NY pp.
222-225.
Functional Group 2. 1989. Living with the Lakes: Challenges and Opportunities Annex B Environmental features.
Processes and Impacts: an Ecosystem perspective on the Great Lakes-St. Lawrence River System. International Joint
Commission Water Levels Reference Study. 169 pp. + Appendices
Great Lakes Basin Commission. 1981. Great Lakes Basin Plan: Wetlands Policy Plan with Final Environmental
Impact Statement. Ann Arbor, Michigan, 43 pp. In Functional Group 2, (1989).
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Headrick, M.R. 1976. Effects of Stream Channelization on Fish Populations in the Buena Vista Marsh, Portage
County, Wisconsin.
Office of Biological Services, Fish and Wildlife Service, 38 pp.
Herdendorf, C. E. and S. M. Hartley, and M. D. Barnes, eds. 1981. Fish and wildlife resources of the Great Lakes
coastal wetlands within the United States. Volume one: Overview. U. S. Fish and Wildlife Service. Washington, D.
C. FWS/OBS-81/02-vl. 469 pp.
Herdendorf, C. E., C. N. Raphael and W. G. Duffy. 1986. The Ecology of Lake St. Clair Wetlands: A Community
Profile. Fish and Wildlife Service. U. S. Dept. of the Interior, Washington, D. C.
Hurley, D.A. and WJ. Christie. 1977. "Depreciation of the Warmwater fish community in the Bay of Quinte, Lake
Ontario," Jour. Fish. Res. Board Canada. Vol. 34: 1849-1860.
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Water Quality. 74 pp.
62
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International Lake Erie Regulation Study Board. 1981. Lake Erie Water Level Study. Report to the International
Joint Commission, Windsor, Ontario, 166 pp.
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Aquatic Habitat. Ontario Ministry of Natural Resources (unpublished).
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Reality. Proceedings: International Symposium on Wetlands of the Great Lakes, Niagara Falls, NY pp. 226-230.
Kahl, R. 1991. Boating Disturbance of Canvasbacks during migration at Lake Poygan, Wisconsin. Wildl. Soc. Bull.
19:242-248
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Wetlands. Proceedings: International Symposium on Wetlands of the Great Lakes, Niagara Falls, NY pp. 292-295.
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Great Lakes Fish Commission.
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Mazumder, A. and W.D, Taylor, (in press). "Thermal Structure of Lakes in Varying Size and Water Clarity." Limno.
Oceanogr.
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Aquatic Habitat and Wetlands - SOLEC Background Paper 63
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Getting, R. B, 1985, Restoration of canvasback migration habitat in the lake states. Presented at Waterfowl in Winter
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Minn. 12 pp.
Patterson, N. 1994. SOLEC Habitats and Wetlands Working Paper: Environmental Conservation Branch Contribution.
Environment Canada, Environmental Conservation Branch (unpublished).
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Prokes, J. A. 1990. Status and Trends of Wetland Mitigation Practices in Southeastern Michigan: An Agenda for the
1990's. Proceedings: International Symposium on Wetlands of the Great Lakes, Niagara Falls, NY pp. 231-240.
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1972. Transactions of American Fisheries Society 1Q5(1):32-40.
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Santos, Kim. 1994. Personal Communication.
Schloesser, D. W. and B. A. Manny. 1990. Decline of Wildcelerv buds in the lower Detroit River. 1950-1985. J.
Wildl. Manage. 54(l):72-76.
Schloesser, D. W. and T. F. Nalepa. in press. Dramatic decline of Unionid bivalves (Bivalvia: Unionidae) in offshore
waters of Western Lake Erie after infestation by the zebra mussel, in press Can. J. Aquat. Sci.
Sprunt, A., IV, W. B. Robertson, S. Postupalsky, R. J. Hensel, C. C. Knoder, and F. J. Ligas. 1973. Comparative
productivity of six bald eagle populations. Trans. No. Am. Wildl. Nat. Res. Conf. 38:96-106.
Superior Work Group. 1993. Ecosystem Principals and Objectives for Lake Superior Discussion Paper. Lake Superior
Binational Program, State of the Lake Superior Basin Reporting Series Volume IV. 16 pp.
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Opportunities., Great Lakes Program, Chicago, Illinois 118pp.
Trauger, D. L., and J, R. Serie. 1974. Looking out for the canvasback. Part III. Ducks Unlimited 38(5):44-
45,60,64,71-72.
U.S. Army, Corps of Engineers. 1987. Corps of Engineers Wetlands Delineation Manual.
U.S. Army, Corps of Engineers. 1989. Final environmental impact statement supplement II; operations, maintenance
and minor improvements of the Federal facilities of Sault Ste. Marie. Michigan (July 1977) Operation of the lock
facilities to 31 January + 2 weeks. Detroit,
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strategy for Cooperation.
U.S. Fish and Wildlife Service. 1988, Final Fish and Wildlife Coordination Act Report on Biological Resources
Impacted by the proposed Navigation Season Extension to January 31+2 weeks on the Upper Great Lakes. East
Lansing Michigan Enhancement Field Office, 183 pp + appendices.
U.S. Fish and Wildlife Service. 1993. Listed Species and Designated Critical Habitat that may be affected by the
Great Lakes Water Quality Guidance.
64
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Weller, M. W. and C. E. Spatcher, 1965, Role of habitat in the distribution and abundance of marsh birds. Agr.
Home Econ. Exp. Sta, Iowa State University Special Report No. 43 Ames. 31 pp.
Weller, M. W. and L, H. Fredrickson. 1973. Avian Ecology of a Managed Glacial Marsh. Iowa Agr. and Home
Econ. Expt, Sta. No. 7403, 22 pp.
Wetzel, R. G. 1992. Wetlands as Metabolic Gates. J. Great Lakes Res. 18(4):529-532.
Whillans, T.H. 1980. Feasibility of Rehabilitating the Shore Zone Fishery of Lake Ontario. Background paper for
the Lake Ontario Fisheries Tactical Plan prepared under the contract to the Lake Ontario Tactical Planning
Committee. OMNR.
Whillans, T.H. 1982. Changes in marsh area along the Canadian shore of Lake Ontario. J. Great Lakes Res. 8(3):
570-577,
Whillans, T.H., R.C. Smardon, and W.-D. Busch. 1992. Status of Lake Ontario Wetlands. Great Lakes Research
Consortium Working Paper, SUNY College, Syracuse, New York.
White, RJ. 1975. Trout population responses to streamflow fluctuation and habitat management in Big Roche-a-Cri
Creek, Wisconsin. Verhandlungen, Internationale Vereinigung fur Theoretische und Angewandte Limnologie.
19:2469-2477.
Wilcox, D. A., J. E. Meeker, and J. Elias. 1992. Impacts of Water-level regulation on wetlands of the Great Lakes.
Phase II Report to Working Committee 2. OC Water Level Reference Study
8.1 Other Sources Used
Erickson, R,E. and M.E. Hubbell. 1992. Atlas of the National Wetlands Inventory Maps in the
Chicago Metro Area. U.S. Fish and Wildlife Service, National Wetlands Inventory (Twin Cities),
MN. 20 pp. and Appendices.
Smith, G.S. 1991. NWI MAPS MADE EASY: A User's Guide to National Wetlands Inventory
Maps of the Northeast Region. U.S. Fish and Wildlife Service, National Wetlands Inventory,
Newton Corner, MA. 15 pp.
U.S. Fish and Wildlife Service. 1985. USER'S GUIDE National Wetlands Inventory Information
and Legend for Map Products. Portland, OR. 12 pp.
U.S. Fish and Wildlife Service. 1990. Photo Interpretation Conventions for the National
Wetlands Inventory. St. Petersburg, FL. 45 pp. and Appendices.
U.S. Fish and Wildlife Service. 1991-1992. Unpublished National Wetlands Inventory Fact
Sheets and Information.
U.S. Fish and Wildlife Service. 1993a. NWI MAPS MADE EASY A User's Guide to National
Wetlands Inventory Maps of the Mountain-Prairie Region. Denver, CO. 16 pp.
Aquatic Habitat and Wetlands - SOLEC Background Paper 65
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Under "Recommendations and Suggested Actions" above, we quoted:
U. S. Department of the Interior. The Impact of Federal Programs on Wetlands. Vol. II, A Report
to Congress by the Secretary of the Interior, Washington DC, 1994,
8.2 Acknowledgements
The following individuals contributed input, information, assistance or ideas helpful to the
compilation of this cluster paper:
Ron Erickson and Kim Santos, U.S. Fish and Wildlife Service, National Wetlands Inventory,
Bloomington, Minnesota.
Tom Dahl, National Biological Survey, National Wetlands Inventory, St. Petersburg, Florida.
Darryl York, National Biological Survey, Information Transfer Center, Ft. Collins, Colorado,
John Gannon, Bruce Manny, Doug Wilcox, and Tom Edsall, National Biological Survey-Great
Lakes Center, Ann Arbor Michigan.
Bob Beltran, Environmental Protection Agency, Great Lakes National Program Office, Chicago
Illinois.
David Rankin, The Nature Conservancy, Great Lakes Program, Chicago, Illinois.
Paul Botts, Chicago, Illinois.
Bob Payne, Agricultural Stabilization and Conservation Service, East Lansing, Michigan.
Tom Kerr, U.S. Fish and Wildlife Service, Refuges and Wildlife, Twin Cities, Minnesota.
Tom Busiahn, U.S. Fish and Wildlife Service, Fishery Resources Office, Ashland, Wisconsin.
Carolynn Bohan, U.S. Fish and Wildlife Service Great Lakes Coordination Office, East Lansing,
Michigan.
Alastair Mathers, Rob MacGregor, Arunus Liskaukas, Ed Iwachewski, Jim Atkinson and their
associates in the Great Lakes Branch, Ontario Ministry of Natural Resources.
Nancy Patterson and associates in the Canadian Wildlife Service of Environment Canada.
Members of the SOLEC Steering Committee and Technical Subcommittee.
We apologize to anyone inadvertently overlooked, or whose comments on earlier drafts could not
be addressed due to time constraints.
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9.0 Post-conference Addendum
This was prepared in response to the five "Participant's Question and Comment Forms" and two
comment letters provided by the Conference Organizers.
General
On the basis of comments received concerning several of judgement-based habitat assessments,
further information suggests these may be taken out of context and misused. The author of this
comment didn't provide subjective corrections to any of these judgments as they appeared in the
tables, however. The working paper authors feel that they serve a purpose in providing
something to start with and do not believe the potential for misuse is significant. They have been
clearly identified as professional judgment from the outset, and this judgment is being relied upon
only until the sorely-needed information called for in the Working Paper becomes available.
Definition of Habitat
One comment concerning the definition of habitat suggested that food and cover resources
should be discussed with it. The early drafts of this paper had no "definition of habitat" because
it means so many different things to so many different Great Lakes species. The authors added
a definition which was particularly broad and uncomplicated because of the audience and scope
of the paper.
Recommendations and Suggestions for Action
Comments also included a caution that the recommendations and suggestions for action provided
in the final section may be premature based on the acknowledged lack of sufficient information
to assess impacts. Further information suggests that these recommendations and suggestions for
action were not out of line. The first priority articulated in the "Loss of Biodiversity" sessions
at SOLEC was "a comprehensive information base and species inventory but action to protect
biodiversity should be undertaken simultaneously" (The SOLEC Indicator, 10/27/94).
Additionally, another comment noted the need for a cost-benefit analysis. A Participant Question
and Comment Form contained the following:
"Financial policies are mentioned in several parts of the SOLEC paper, and a recent
Federal report points out how U. S. Federal financial support has had negative impacts.
'Restricting federal financial support for unsound development cannot be relied
on as the only conservation tool. It will help to conserve the remaining resource
base, but it cannot mitigate for lost wetlands or restore degraded ones. It should,
however, be among the first approaches to the problem of continuing wetland loss
and degradation. Many [U.S.] federal programs that affect wetlands adversely are
designed and financed in ways that violate the beneficiary pay principal of public
finance. These programs distort market signals and provide subsidies that have
Aquatic Habitat and Wetlands - SOLEC Background Paper 67
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had negative environmental effects. Optimally, these programs should be
redesigned in order to confront those who benefit from the programs and projects
with the full cost of their activities. If an activity cannot pay for the full cost of
the resources which it uses, it is inefficient to allocate the resources to it by
subsidization and inequitable to ask taxpayers to finance the costs.'
The same report, released after fmalization of the SOLEC paper, made one major
recommendation for the Great Lake state it described:
'Have federal agencies assess the effects of their programs on wetlands. Where
feasible, agencies should minimize the wetlands effects of their programs.'
These impacts are also occurring in the Canadian portion of the Basin, similar solutions
may apply." (Reference in "Peer-Reviewed References" section below).
Rate of Net Loss
On the basis of comments received concerning Section 5.4, which quoted a 20,000 acre per year
loss estimate made by the Great lakes Basin Commission (1981) and Functional Group 2 (1989),
further information suggests it may not reflect the current situation. This estimate was included
in the Working Paper because it was the only guess made, on a Great Lakes Basin-wide scale,
of the magnitude of the ongoing net loss before or since that time. The working paper authors
would have gladly quoted another conjecture but none was found for the basin-wide scale. It
points up a lack of "common currency" between jurisdictions, states, provinces and nations that
was obvious from the Working Paper and presentation of it at SOLEC. The comment form
making this point, from the Michigan Department of Natural Resources, went on to state that
many state and federal regulatory programs, land acquisition, tax incentive and financial
assistance programs are in place to protect and restore aquatic habitat resources. Very strong
authorities and laws exist in the State of Michigan to protect coastal wetlands, lakes and streams
as well as inland wetlands. The authors could conclude from this argument that the rate of net
loss has been substantially reduced, however the data upon which the original estimate was made
is over 20 years old and no one has stepped forward to publish a better one since. Identifying
this data gap justifies SOLEC.
Influencing Decision-Making
The remainder of the Working Paper Breakout Session Participant's Question and Comment
Forms related to the issue of how we as scientists and managers can influence decision making.
One comment stated that the two important items that influence politicians or decision makers
to make worthwhile decisions are votes and dollars. The comment urges lobbying and
identifying what influences votes. The comment also urges quantifying in economic terms the
benefits of protecting or restoring habitat. Another comment form asked: "With such a huge
portion of the original wetland habitat acreage altered or converted to different land usage types,
shouldn't there be a moratorium on any future alteration or conversion? Shouldn't all remaining
wetland habitat be regarded and classified as critical?" Understanding wetland values and
functions withing the larger Great Lakes St. Lawrence River Ecosystem, such as the information
eventually publicized for the Everglades, the comment went on to say, would strengthen
arguments for Great Lakes wetland preservation. Another comment stated that recreational and
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economic values need to be considered functions that should be considered as indicators of
significance. The authors agree. That same comment suggested adding more to the Lake-by-
Lake descriptions to fully describe the wetlands of significance and impacts that have occurred.
This would have increased the size of the document considerably, which was beyond the
recommended size almost from the start. It is nonetheless a worthy goal, and could make a
useful outgrowth document. The information is available from diverse sources. Other details
were noticed in this comment letter, including lack of solutions for introduced species like carp
and purple loosestrife, and major research initiatives at the University of Guelph directed at
controlling purple loosestrife. More Canadian habitat restoration data is becoming available and
should be included in the next SOLEC. In general this letter found that impoundment projects
in Canada have been very successful while experimental techniques remain questionable.
Mitigation failures were felt by the author of this letter more closely linked to execution of the
effort. Finally, this letter called for selective use of impoundments rather than what was perceived
in Action 4 at the bottom of page 57 to be a total ban on diking. The authors agree that there
need not be a rigid ban against all diking, rather the important point is not to "totally isolate
wetlands from the lake and reduce wetland functions." Need for this level of detail was not
anticipated.
Another comment stated that the paper needed a stronger pitch for a universal
"ranking/classification" system as crucial for decision-making. It was not the authors' intent to
recommend one system over another, and a critical evaluation of the myriad systems in use was
certainly beyond the scope of what was originally supposed to be limited to a 30-page paper.
The same comment recommended an International Joint Commission committee/Forum on this
issue. The authors would support this idea. The comment also called for targetted
communication, education and involvement plans, particularly for community-based grass roots
involvement and buy-in. Finally, this comment asked for economic and human health integration
of issues. The message should be that we need a healthy ecosystem in order to be healthy
physically and economically. If we promote mat more, and quantify it, then the policy changes,
etc. will come. The authors and the SOLEC Integration paper support this message, but again
showing it is beyond the scope of the Habitat Paper,
Partners
On the basis of comments received concerning protection of shorebird habitats and partner
agencies in the Eastern Habitat Joint Venture, the authors acknowledge leaving out some details.
We apologize to the Partners in the Eastern Habitat Joint Venture, who are:
Canadian Wildlife Service
Ministry of Natural Resources
Ministry of Agriculture, Food and Rural Affairs
Agriculture Canada
Nature Conservancy of Canada
Wildlife Habitat Canada
Aquatic Habitat and Wetlands - SOLEC Background Paper 69
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Peer-Reviewed References
One comment asked for a greater number of peer-reviewed reference citations, which "would be
a useful addition to the paper." The authors felt great frustration at the lack of current basinwide
habitat data. This necessitated piecing together what information was out there in grey literature
reports in order to give any kind of a Great Lakes basinwide summary. The lack of information
was acknowledged in the paper, but we were certainly not in the position of being able to
generate research reports on our own, on a basinwide scale, to distill down to what was originally
supposed to be a 30-page summary paper. We hope identification of this gap will stimulate other
Great Lakes basinwide habitat data to be published in a peer-reviewed form. It is sorely needed.
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STATUS OF NATIONAL WETLANDS INVENTORY
DISTRIBUTION
MAPS AVAILABLE
DRAFT MAPS
AVAILABLE
THIS GRAPHIC SHOWS GENERALIZED INFORMATION. FOR DETAILED INFORMATION
ON SPECIFIC AREAS, TELEPHONE 1-800-USA-MAPS (IN VIRGINIA 1-703-648-6045).
FEBRUARY 1994
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