Lakes Ecosystem Conference 2008
JL* **
Background Paper
AREAS
OF THE GREAT LAKES
2009
by the Governments of
Canada
and the
United States of America
Prepared by
Environment Canada
and the
U.S. Environmental Protection Agency
September 2009
oEPA
Canada
-------
Environment Canada
and
United States Environmental Protection Agency
ISBN 978-1-100-13562-5
EPA905-R-09-013
CatNo.Enl64-19/2009E
10% Post Consumer Waste. Acid Free.
Cover Photo Credit: Door County lakeshore, U.S. EPA, Karen Holland
NEARSHORE AREAS OF THE GREAT LAKES 2009
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TABLE OF CONTENTS
1.0 INTRODUCTION. Elizabeth K. Hinchey (Illinois-Indiana Sea Grant) and Rita Cestaric
(U.S. EPA GLNPO) i
2.0 IMPACTS OF LAND USE CHANGE ON THE NEARSHORE. Scudder Mackey (Habitat
Solutions NA) 4
3.0 THE LAND BY THE LAKES: NEARSHORE TERRESTRIAL ECOSYSTEMS. Dan Kraus and
Gary White (Nature Conservancy Canada) 13
4.0 GREAT LAKES COASTAL WETLAND ECOSYSTEM. Karen Rodriguez (U.S. EPA GLNPO)
and Krista Holmes (Environment Canada) 40
5.0 NEARSHORE WATERS OF THE GREAT LAKES 49
5.1 Nutrients and the Great Lakes Nearshore, Circa 2002-2007. John R. Kelly (U.S. EPA) 49
5.2 Nonindigenous Species (NIS). Kristen Holeck and Edward Mills (Cornell University),
Hugh Maclsaac (Great Lakes Institute for Environmental Research, University of
Windsor), and Anthony Ricciardi (Redpath Museum, McGill University) 61
5.3 Viral Hemorrhagic Septicemia in the Great Lakes. Ken Phillips (U.S. Fish and
Wildlife Service) and Elizabeth Wright (Ontario Ministry of Natural Resources) 65
5.4 Cladophora in the Great Lakes: Guidance for Water Quality Managers. Marty
Auer (Michigan Technical University) and Harvey A. Bootsma (Great Lakes WATER
Institute, University of Wisconsin-Milwaukee) 69
5.5 Harmful Algal Blooms (HABs) in the Great Lakes: Current Status and Concerns.
Sue Watson (Environment Canada) and Gregory L. Boyer (Great Lakes Research
Consortium, State University of New York) 78
5.6 Human Health. Shelley Cabrera (Oak Ridge Institute for Science and Education
fellowship program with U.S. EPA) 92
5.7 Type E Botulism. Chiara Zuccarino-Crowe (Oak Ridge Institute for Science and
Education fellowship program with U.S. EPA) 99
5.8 Nearshore Habitats of the Great Lakes. Scudder Mackey (Habitat Solutions NA) 104
5.9 Nearshore Physical Processes. Scudder Mackey (Habitat Solutions NA) 108
NEARSHORE AREAS OF THE GREAT LAKES 2009
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NEARSHORE AREAS OF THE GREAT LAKES 2009
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1.0 Introduction
Notice to Readers
This background paper is intended to provide a concise overview of the status of the nearshore conditions in the Great Lakes.
The information presented by the authors was selected as representative of the much greater volume of data, and therefore does
not include all research or monitoring information available. The chapters were prepared with input from many individuals
representing diverse sectors of the Great Lakes community.
The intent of this paper was to provide the basis for discussions at SOLEC 2008. Participants were encouraged to provide
additional specific information and references for use in preparing the final, post-conference version of the paper. Together with
the information provided by SOLEC discussants, the paper is part of the 2009 State of the Great Lakes reports. These reports
provide key information required by managers to make informed environmental decisions.
The Nearshore Areas of the Great Lakes
The theme for SOLEC 2008 was "The Nearshore." In 1996. SOLEC focused on the nearshore lands and waters of the Great Lakes
where biological productivity is greatest and where humans have maximum impact. In 2008. the conference concentrated on what
has changed with respect to the nearshore environments since 1996. Additional conditions and issues not evaluated in 1996 were
also addressed.
Several Great Lakes indicators were identified for the SOLEC grouping "Coastal Zones." but only a few were reported. To enhance
the discussions by participants at SOLEC 2008. a more comprehensive summary about the current environmental conditions in the
nearshore area was desired. This background paper on the current status of nearshore areas of the Great Lakes, authored by Great
Lakes expert researchers and managers, strives to provide this summary.
For SOLEC 1996, four background papers about the nearshore zones were prepared: Impacts of Chunking Land i'sc (Thorp ci
al. 1997); The Land by the Lakes: \earshore Terrestrial Ecosystems (Reid and Holland 1997): Coastal Wetlands (Maynard and
Wilcox 1997); and \earshore Haters of the Great Lakes (Edsall and Charlton 1997). They are summarized in the document "Suite
of the Lakes Ecosystem Conference 1996: Highlights of Background Papers" available at www.epa.gov glnpo solec M>lec ll>9(\
For SOLEC 2008. the chapters in this background paper focus on the question. "What has changed since 1996?" Assessments of
current environmental conditions or issues that were not evaluated in 1996 are also included. Each chapter was intended to include:
• an assessment of the State of the Ecosystem, which describes the status (good. fair. poor, or mixed) and trends (improving.
deteriorating, or unchanging) of the ecosystem component in question, presented lake-by-lake, if appropriate.
a discussion of current and future pressures that could be expected on the nearshore environment.
• suggested management implications to mitigate the pressures.
For this paper, "nearshore" is defined as beginning at the
shoreline or the lakeward edge of the coastal wetlands and
extending offshore to the deepest lakebed depth contour
where the thermocline typically intersects with the lakebed
in late summer or early fall (Edsall and Charlton 1997. Fig.
1). It should be noted that other definitions of the nearshore
exist. For example. Mackey 2009a defines nearshore :ones
as areas encompassed by water depths generally less than
15 m. Mackey 2009b further defines the nearshore as
"including higher energy coastal margin areas and lower
energy nearshore open-water areas." Coastal margin areas
are located between ordinary high water (OHW) and the
3-m isobath, where the shoreward limit is defined by the
intersection of the OHW with a beach, bluff, revetment.
seawall, or other shoreline feature (Mackey 2008b).
Substrates are generally coarser-grained than those found
in deeper water and may be highly mobile in response to
Legend
Nearshore waters
Figure 1. Nearshore waters of the Great Lakes.
Source: Adapted from Edsall and Charlton (1997).
0 100 200 Km
NEARSHORE AREAS OF THE GREAT LAKES 2009
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wave-driven littoral processes. Nearshore open-water areas are located between the 3-m isobath lakeward to the 15-m isobath
(Mackey 2008b). This area is dominated by processes more characteristic of the open-lake, but are also subject to higher wave
energies and associated littoral or nearshore processes during major storm events. Substrates are generally finer-grained, but may
be reworked during storm events. These nearshore subdivisions are based on the concept that habitat zones can be defined, in
part, by the dominant physical processes that act within those zones, with boundaries constrained by existing limnological and
biological datasets (Johnson et al. 2007).
Progress from 1996-2008
In 1996, the authors of the Nearshore Waters paper commented that among the most destructive human activities for the nearshore
waters has been the introduction of exotic species. In 1996, there were -166 documented invasions of non-indigenous aquatic
species in the Great Lakes since the early 1800s. In 2008, at least 184 invasions were reported. Although nutrient loadings to the
Great Lakes have been reduced in the past 30 years, many physical, chemical and biological changes to the nearshore environment
remain. The current authors also discuss emerging issues that affect the nearshore environment: botulism, harmful algae blooms,
viral hemorrhagic septicemia (VHS), and shoreline development, among other stressors. VMS, a deadly fish virus and an invasive
species that is threatening Great Lakes fish, is not constrained to nearshore environments, but it does affect nearshore fish
populations, and human activity could be a factor in its spread.
The authors of 1996 Nearshore Terrestrial-Land by the Lakes paper concluded that the most pressing need for this ecosystem
component was a conservation strategy that would protect ecologically significant ecosystems within 19 geographic "biodiversity
investment areas." In 2006, The Nature Conservancy Great Lakes Program and the Nature Conservancy of Canada Ontario Region
released the Binational Conservation Blueprint for the Great Lakes. The Blueprint identified 501 areas across the Great Lakes that
are a priority for biodiversity conservation for their exceptionally unique and diverse species, communities and physical features.
The main finding of the 1996 Impacts of Changing Land Use paper was that development of farm and natural lands in both urban
and rural areas presented the single largest threat to the Great Lakes basin ecosystem. Indeed, the current author of the Impacts
of Land Use Change on the Nearshore chapter noted that the continued rapid expansion and growth of urban and suburban areas
and associated infrastructure is the single most significant land use/land cover change (~60%) within the U.S. portion of the
Great Lakes basin over the last decade. Much of the newly developed land was converted from agricultural or early successional
vegetation lands. Moreover, in the Chicago area, changes in urban and suburban land use between 1992 and 2001 (19%) far
exceeded those predicted based on population growth (2.2%). The role that higher crop prices (driven by investments in biofuel
production) may play in the decline in the loss of agricultural lands is also explored.
The authors of the 1996 Coastal Wetlands of the Great Lakes paper acknowledged that although the more than 216,000 hectares
(534,000 acres) of Great Lakes coastal wetlands are a considerable ecological, biological, economic and aesthetic resource, there
were not enough detailed and comprehensive data about the coastal wetlands to report confidently on their current conditions
and trends in viability, health, or success of current protection and restoration efforts. They suggested the development of coastal
wetland indicators in the following categories: physical and chemical, individual and population level, wetland community,
landscape, and social and economic. They also suggested the following management challenges:
• "There is no comprehensive inventory and evaluation of Great Lakes coastal or even inland wetlands."
• In the U.S., "Individual states have also completed wetland inventories and evaluations, however methodologies are not
consistent and the level of detail and amount of field-based data varies."
• "Work has been initiated to develop indicators for wetland degradation and to choose monitoring sites and appropriate
monitoring strategies. However, there is no international consensus on these matters."
In 2000, the U.S. Environmental Protection Agency (U.S. EPA). Great Lakes National Program Office (GLNPO) funded the
creation of the Great Lakes Coastal Wetlands Consortium to expand the coastal wetland monitoring and reporting capabilities of
the U.S. and Canada under the Great Lakes Water Quality Agreement. The purpose of the Consortium was to design a long term,
NEARSHORE AREAS OF THE GREAT LAKES 2009
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binational coastal wetland monitoring program. Indicators suggested through the SOLEC process were evaluated and protocols
tested. In early 2008, a final report detailed indicators, protocols for monitoring, and costs. Major accomplishments include:
• A map of the more than 216,000 hectares (534,000 acres) of known coastal wetlands
• A new classification system consisting of three major categories: lacustrine, riverine, and barrier-protected that was then
applied to the mapped coastal wetlands
• Field-tested sampling protocols
• A statistical sampling design
• A database that will house future data
These and other improvements in assessing coastal wetlands from 1996 to the present day are detailed in this report in the chapter
Great Lakes Coastal Wetland Ecosystem.
Acknowledgments
Authors:
Elizabeth K. Hinchey, Illinois-Indiana Sea Grant liaison to the U.S. EPA GLNPO, hinchey.elizabeth@epa.gov
Rita Cestaric, Program Analyst, U.S. EPA GLNPO, cestaric.rita@epa.gov
Information Sources
Edsall, T.A., and Charlton, M.N. 1997. Nearshore Waters of the Great Lakes. State of the Lakes Ecosystem Conference 1996
Background Paper.
Johnson, L.B., Ciborowski, J.J.H., Mackey, S.D., Hollenhorst, T., Gauthier, R., and Button, D.T. 2007. An integrated habitat
classification and map of the Lake Erie basin: Final report. National Fish and Wildlife Foundation, U.S. EPA. pp. 25.
Mackey, S.D. 2009a. Nearshore Habitats of the Great Lakes. State of the Lakes Ecosystem Conference 2008 Background Paper.
Mackey, S.D. 2009b. Impacts of Land Use Change on the Nearshore. State of the Lakes Ecosystem Conference 2008 Background
Paper.
Maynard, L., and Wilcox, D. 1997. Coastal Wetlands. State of the Lakes Ecosystem Conference 1996 Background Paper.
Reid, R., and Holland, K. 1997. The Land by the Lakes: Nearshore Terrestrial Ecosystems. State of the Lakes Ecosystem Conference
1996 Background Paper.
Thorp, S., Rivers, R., and Pebbles, V. 1997. Impacts of Changing Land Use. State of the Lakes Ecosystem Conference 1996
Background Paper.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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2.0 Impacts of Land Use Change on the Nearshore
^
ta
Introduction
As termed in the SOLEC 1996 background paper on Nearshore Waters of the Great Lakes, development is defined as "human use of
land connected with industrial, residential, agricultural, and transportation activities that substantially alters the natural landscape
or affects the ecosystem." Virtually the entire Great Lakes basin has been altered or impacted by anthropogenic activities due to
development, and these changes have both directly and indirectly impacted the nearshore areas of the Great Lakes. Significant
anthropogenic changes began more than 150 years ago as the Great Lakes basin was settled and natural areas (forests, prairie.
and wetlands) were converted to agricultural and urban use. Many of these changes continue today. The focus of this background
paper is explore how continuing changes in the land use and land cover may directly or indirect!) impact nearshore zones of the
Great Lakes.
Environmental Zone
Coastal Margin
OHW -3m Isobath
Nearshore Open Water
3 m - 1 5 m Isobath
Low Energy Area
Embayments,
tributary mouths,
coastal wetland habitats
Open water area - water
depths greater than 10 m
Limited Exposure
Short Fetch Distance
Fine-grained, soft
substrates
High Energy Area
Open Coasts,
island fringes
Open water area - water
depths less than 10m,
shallow reef complexes
Open Exposure
Long Fetch Distance
Coarse-grained, hard
substrates, bedrock
The Nearshore
For the purposes of this discussion, the "nearshore"
includes higher energy coastal margin areas and
lo\\ er energy nearshore open-water areas (Table 1).
(\Hisial margin areas are located between ordinary
high water (OHW) and the 3-m isobath, where the
shoreward limit is defined by the intersection of
the OHW with a beach, bluff, revetment. sea\\all.
or other shoreline feature. Substrates are generally
coarser-grained than those found in deeper water
and may be highly mobile in response to \\axe-
driven littoral processes, .\earsliore open-water
areas are located between the 3-m isobath lakeu ard
to the 15-m isobath. These areas are dominated by
processes more characteristic of the open-lake, but
would also be subject to higher wave energies and
associated littoral or nearshore processes during
Table 1. Hydrogeomorphic Characteristics and Dominant Physical
Processes.
Nearshore environmental zones are defined by water depth,
hydrogeomorphic characteristics, and dominant physical processes.
Source: Courtesy of Habitat Solutions NA
major storm events. Substrates are generally finer-grained, but may be reworked during storm events. These subdivisions of the
nearshore are based on the concept that habitat zones can be denned, in part, by the dominant physical processes that act within
those zones with boundaries that are also defined (and constrained) by existing limnological and biological datasets (Johnson et
al. 2007).
Landscapes and Watersheds
The linkages that relate land use change to the nearshore are controlled by physical characteristics of the basin and the processes
that move water across (and through) basin landscapes into the Great Lakes. Unlike watersheds, which are usually delineated by
surface-water hydrology, landscapes are defined by and include the integrated components of land and water area (i.e. geology,
geomorphology. and land cover) upon which natural processes act within the Great Lakes basin (Mackey 2005). Watersheds are a
subset of landscapes and are defined (and limited) by the area that collects surface waters that feed a main stream and associated
tributaries. Even though landscapes are typically considered to represent areas of regional extent, the term is applicable to multiple
scales. Definitions of the integrated components of land and water area include (Mackey 2005):
Geology - surface and subsurface distribution of geologic materials: soils: hydrophysical characteristics (e.g.. permeabi I ity.
porosity, aquifers, aquatards).
Geomorphology - shape, pattern, distribution, and physical features of the land surface: landforms and drainage pattern
(topography, slope, hydrography, channel morphology and bathymetry, connectivity and pattern).
• Land Cover - shape, pattern, and distribution of biological and anthropogenic features on the land surface: land use.
Connecting Landscapes to the Nearshore Zone
The impacts of changes in land use land cover are both direct and indirect. For example, nearshore impacts include fragmentation
and destruction of terrestrial and aquatic habitat; loss of native plant communities and wildlife: altered flow regimes caused by-
water withdrawals, diversions, channelization, and/or redirection of waste and stormwater flows: increased runoff and reduced
groundwater recharge due to "hardening" of the landscape: point, non-point, point, bacterial, nutrient, and atmospheric contaminant
NEARSHORE AREAS OF THE GREAT LAKES 2009
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and pollution discharges; and altered thermal regimes due to power production, channelization, and altered flow regimes (dams
and reservoirs). All of these stressors affect the ecosystem both directly and indirectly and at multiple scales.
Two projects were recently completed that address the affects of changes in land use land cover and impacts of those changes on
the Great Lakes ecosystem. The U.S. EPA-funded Great Lakes Environmental Indicators (GLEI) project developed a suite of
indicators to describe the stressors and stressor gradients acting within the basin at multiple scales. These indicators were developed
using multivariate analyses to assess the response of biological communities to changes in 207 individual bio-physical stress
variables identified in the basin (Niemi a al. 2006). Based on these analyses, an overall Stress Index can be quantified for
individual watersheds within the U.S. Great Lakes portion of the basin (Danz et til. 2007, Fig. 1).
Best
0 100 200 300
Figure 1. The overall Stress Index derived from 207 individual stress
variables for the U.S. portion of the Great Lakes basin by the Great
Lakes Environmental Indicators project.
Source: Modified from Niemi et al. (2008).
What is not well understood are how changes in land
use/land cover that occur many kilometers inland
from the Great Lakes impact the nearshore zones of
the Great Lakes. Landscapes and watersheds are
connected to the Great Lakes via hydrology, i.e.
surface and groundwater flows into the Great Lakes
via rivers and streams. Hydrologic impairments alter
natural flow regimes and contribute to water quality
degradation by increasing surface runoff, sediment
and contaminant loads, and affects how biological
communities utilize energy and materials as water
moves through the system. For example, there is a
time-distance relationship between water and the
benefits that water provides to the ecosystem. The
time that water stays within the system is a function
of flow velocity, direction and distance traveled, and
pathways and connections within, or on. the landscape.
Constrained by existing impairments, the ecological
value of a gallon (or litre) of water varies as a function
of its location and residence time on. or within, the
landscape. This time-distance dependency for riverine systems is clearly demonstrated by the work by Poff ct al. (1997) and
subsequent work by Richter et al. (1998). Richter and Richter (2000), Baron et al. (2003). and others.
A Great Lakes Protection Fund-funded project designed to identify and value hydrologic restoration opportunities at watershed
and subwatershed scales explored ways to assess how ecological benefits of water are related to the pathways that water takes
across, or through, the landscape (Apfelbaum et al. 2007). A set of geospatial analysis tools was developed to link changes in
land use/land cover to hydrologic alteration and impairments in Great Lakes watersheds. These analysis tools can be used to
identify and evaluate potential hydrologic restoration opportunities at multiple scales within the basin. The products of this work
compliment the results of the GLEI project. For example, a screening tool was developed to evaluate variables from more than
20 commonly available geospatial datasets. and as a result identified six fundamental land use land cover variables that when
analyzed statistically can be used to quantify the degree of existing hydrologic impairment for individual watersheds (Apfelbaum
et al. 2007. Fig. 2). When compared with the GLEI overall Stressor Index, the correspondence between these two indices is readily
apparent.
The similarities between indices suggest that biological communities not only respond directly to changes in land use/land
cover, but also to the hydrologic impairments created by those changes in land use/land cover as well. This cause-effect
relationship can be used to assess how changes on the landscape may affect the nearshore zones of the Great Lakes, as
waters flowing across or through the landscape must pass through the nearshore zone into the open lake.
Hydrologic impairments affect not only the ability of natural processes to convey energy, water, materials, and biota, but also alter
the benefits that water provides to the nearshore ecosystem. Both the coastal margin and nearshore open water zones are also affected
by changes in water level and are subject to both direct and indirect anthropogenic impacts, not only at the sediment-water interface.
but in adjacent watershed areas as well. Waters derived from the landscape carry with them sediment, contaminants, and energy-
thai may significantly impact the nearshore zones of the Great Lakes. It is through this hydrologic coupling that changes in land use/
NEARSHORE AREAS OF THE GREAT LAKES 2009
5
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Superior
land cover are transferred across
landscapes into the nearshore
zones of the Great Lakes.
Land Use/Land Change over
the Past Decade
At regional scales, changes in
land use land cover changes are
typically evaluated be comparing
high-resolution multispectral
satellite imagery and or high-
resolution aerial photography
taken at discrete time intervals
(e.g. Fig. 3). To assist in the
development of a new suite
of indicators, recent work by
the U.S. EPA-supported GLEI
project evaluated land use land
cover changes for the period 1992
through 2001 for the U.S. portion
of the Great Lakes basin (Wolter
cial. 2006). Approximately 2.5%
or 798.755 hectares (1.973,766.59
acres) of the U.S. portion of the
(iron! Lakes basin experienced
some type of land use change
between 1992 and 2001 (Table
2. Wolter el ai. 2006). These
changes were dominated by conversion of forested and agricultural lands to either high or low intensity development, transportation
(roads), and-or early successional vegetation (upland grasses and brush). Low-intensity development increased by 33.5°o. high-
intensity development increased by 19.6%. and
transportation (road) area increased by 7.5%. The
continued rapid expansion and growth of urban
and suburban areas and associated infrastructure
is the single most significant land use/land cover
change (-60%) within the L.S. portion of the Great
Lakes basin. Much of the newly developed land was
converted from agricultural or early successional
vegetation (ESV) lands. Moreover, in the Chicago
area, Auch et al. (2004) found that changes in
urban and suburban land use between 1992 and
2001 (19%) far exceeded those predicted based
on population growth (2.2%) (Wolter et al. 2006).
Forested and agricultural lands decreased by -2.3%
each, which is a significant decline from the 9.8% loss
reported by U.S. EPA for the previous decade (Wolter
et al. 2006). This decline in the loss of agricultural
lands may be related to higher crop prices that may
be driven by investments in biofuel production. This
topic is discussed more fully below.
Legend
rcmsa Demonstration
3 Watersheds
Impairment Score
•• Very Low
Medium
'' High
•• Very High
Figure 2. Relative potential surface hydrologic impairment (U.S. Great Lakes basin).
Relative hydrologic impairment derived from six hydrologic variables for 8-digit HUC
watersheds for the U.S. portion of the Great Lakes basin.
Source: Apfelbaum el a/. (2007).
Wolter et al. 2006 grouped the most common land
use changes into 10 transition categories which can
then be summarized into three general types of land
Figure 3. False color change composite of Landsat sensor data
showing land use/land cover changes (yellow) in the Detroit Michigan
area between 1992 and 2001.
Source: Wolter et al. (2006).
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Shoreline Buffer Zones
Attribute Measured
Total area (ha)
Area unchanged (ha)
Area changed (ha)
Percent of area changed
Percent of area unchanged
Non-developed to developed (ha)
% of buffer area
% of basin area
% of all basin transitions
% of basin non-dev. to dev.
0-1 km
647,440
616,447
30.994
4.8%
95.2'
151,889
2.3%
0.1%
1.9'
- •
0-5 km
2,686,163
2.592.019
94,144
3.5%
96.5
50.145
1.9%
0.2%
• 3
12.7%
0-10 km
4,936.957
4,777,057
160,120
3.2%
96.8%
83,592
1.7%
10.5'
21.2%
Whole
Basin
31,525.961
30,727,206
798,755
2.5%
97.5%
393.719
49.3%
100.0%
Table 2. Change in non-developed land to developed land for the period 1992 to 2001
within buffer zones located 0-1 km, 0-5 km, and 0-10 km landward from U.S. Great Lakes
shorelines.
LULC data are based on a comparison of 1992 NLCD and GL2001 land use land cover
change datasets.
Source: Wolter el a/ (2006)
250
use change - agriculture to developed
(210.068 hectares (519.089.33 acres)
or 26.3%), forest to early successional
vegetation (180.690 hectares
,446.494.71 acres) or 22.6 %). and
forest to developed land (154,681
hectares (382,225.08 acres) or 19.4 " „).
Figure 4 illustrates the 10 transition
categories and dominant types of land
use change that have occurred during
the period 1992 through 2001.
Pastor and Wolter (2002) describe how
certain types of land use/land cover
transitions are transient and short-
term. For example, conversion of forest
to non-developed lands such as early
successional vegetation will be short-
lived as those lands will succeed back
into forest cover. However, conversion
of forest to developed residential or
commercial lands will likoh bo long-
term, as the probability of conversion
back into undeveloped forest lands
is extremely low. Within the U.S.
portion of the Great Lakes basin.
~49% of the land use/land cover
changes that occurred between 1992
and 2001 were from non-developed
to developed land with minimal
probability of being converted
back into a natural state (Wolter el
al. 2006). Note also that two of the
three types of general land use change
are considered to be permanent and
long-term.
In addition to population growth
and economic development, recent
increases in the price of diesel fuel and
gasoline in combination with Federal
(U.S.) subsidies for biofuel production
have made crop and < or land use
conversion to row-crop agriculture
(e.g. corn, soybeans) economically attractive. Most of these changes have occurred after the Wolter ci ul. 2006 paper was published
and therefore are not included in available land use land cover chango analyses.
Even though Federal subsidies for ethanol production are not new. the price of gasoline and desire for renewable fuel sources have
contributed to a doubling of the price of corn and soybeans in the U.S. that started in 2005 (Fig. 5(. Higher prices may provide
an economic incentive to increase corn or soybean production by converting agricultural or other natural lands into row crop
agriculture. If this conversion occurs, it is anticipated that sediment, nutrient, and agricultural contaminant loadings to Great
Lakes tributaries and nearshore zones will increase.
Forest to Early
Succesional Veg
Land Use/Land Cover Change Category
Figure 4. Distribution of land use / land cover change categories for the whole basin.
Three change categories were dominate between 1992 and 2001 - Agriculture to
Developed, Forest to Developed, and Forest to Early Successional Vegetation (ESV).
Source: Wolter el al. (2006).
NEARSHORE AREAS OF THE GREAT LAKES 2009
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However, fuel and crop price increases are a recent phenomena (since 2005), and currently available land use/land cover
change mapping does not adequately capture these potential changes in land use. In fact, an examination of annual crop
planting data for Midwestern States suggests that crop
switching and or conversion to agricultural lands has not
yet occurred (Fig. 6). Moreover, the LSDA and most state
agricultural agencies do not (currently) capture statistical
data for crops grown for biofuels production. A possible
indicator of land use conversion (and/or crop switching)
would be the percentage of crops (corn or soybeans) grown
for biofuels production within a watershed.
Wolter et at. (2006) also analyzed land use/land cover changes
within three buffer zones adjacent to the coast: 0 to 1 km.
1 to 5 km. and 5 to 10 km from the coastline. Within these
buffer zones, the dominant land conversion is from forested
land to developed land. The results of these analyses show
that more than 21% of the newly developed land within the
basin occurred within 10 km of a Great Lakes coastline
(Table 2). Of note is the conversion of wetlands into developed
land. 12.8 % within 1 km of the coastline. 14.9 °0 within 1
to 5 km of the coastline, and 10.7°o within 5 to 10 km of the
coastline. Between 1992 and 2001,38.4% of the conversions
from wetland to developed land occurred within 10 km
of a Great Lakes coastline (Wolter et al. 2006). The loss
of wetlands is especially problematic given that they are
supposedly protected by law (e.g. Section 404. Clean Water
Act. 19-2).
Associated with conversion to developed lands (urban.
suburban, and roads) is an increase in imperviousness
that reduces water retention on the landscape, increases
stormwater runoff, and increases sediment, bacterial, and
chemical contaminant loads into the Great Lakes (e.g. Center
for Watershed Protection. 1994. Environment Canada and U.S.
Environmental Protection Agency. 2005). Moreover, areas
immediately adjacent to the coastline typically do not drain
into a stream or river, but directly into the Great Lakes. These
"interfluves" exist between riverine watersheds and may not
have the benefit of riparian wetlands or stormwater treatment
systems to process sediments, nutrients, and contaminants
as in larger riverine watersheds. These sources of sediment
and nutrients may significantly degrade local water quality in
adjacent coastal margin and nearshore areas.
Alterations at the Land-Water Interface (Shoreline
Modifications)
Associated with increasing de%elopment (or redevelopment)
in the 0-1 km buffer zone are physical modifications to the
shoreline to protect property and infrastructure from erosion
caused by waves and flooding during wind-driven storm
events, and to provide recreational and commercial access to
the Great Lakes. These physical modifications to the shoreline
have disrupted coastal and nearshore processes, flow and
littoral circulatory patterns, and altered nearshore habitat
O
CO
o
o
-o- Corn $/bushel
-A- Gas $/gallon
* Soybeans S/bushel
[Soybeans
13.00
12.00
11.00
10.00
9.00
8.00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
Year
Figure 5. Comparison of Ohio Crop and Gasoline Prices,
1992-2007.
Within the Midwest region, higher gasoline prices has created
an increased demand for corn and soybeans to produce
biofuels (ethanol and biodiesel). Since a gas prices have
exceeded $2.00/gallon in 2005, the price for a bushel of corn
(or soybeans) has more than doubled Higher prices may
provide an economic incentive to increase corn or soybean
production by converting agricultural or other natural lands into
row crop agriculture.
Source: USDA, National Agricultural Statistics Service.
Year
Figure 6. 1992 - 2007 Crop Plantings (Ohio Acreage).
Even though prices for corn and soybeans have increased
since 2005, plantings for these crops have not increased.
Note that spring 2008 was extremely wet which may have
significantly reduced planted acreage due to an inability to
get equipment into the fields. Additional data are needed to
confirm that agricultural (or other) lands are being converted to
corn and/or soybean crops in response to a high demand for
biofuels.
Source: USDA. National Agricultural Statistics Service.
NEARSHORE AREAS OF THE GREAT LAKES 2009
-------
structure. For example, anthropogenic alterations to river mouths and the "armoring" of shorelines modify flow paths and disrupt
nearshore coastal processes that create and maintain coastal margin and nearshore habitats.
Many native species require relatively shallow, well-oxygenated waters flowing though coarse gravel and cobble substrates with
protected interstitial spaces. In many cases, spawning areas are adjacent to nearshore nursery areas and rely on regional circulation
patterns to transport larval fish into adjacent nursery areas. Reductions in the volume of available littoral sand has lead to the
"coarsening" of nearshore substrates and the gradual replacement of mobile sand sheets with relatively stable heterogeneous
coarse-grained lag deposits (cobbles and boulders) resting on bedrock or cohesive clay substrates. The loss of protective sand
sheets has significantly altered the pattern and distribution of nearshore aquatic habitats and has created ideal conditions for
colonization by lithophyllic organisms such as dreissenids. round gobies, and other non-native species.
Irrespective of habitat impacts, continued coastal development
(and redevelopment) has led to an increase in the amount of
shore protection along Great Lakes coastlines. Examples of
shoreline protection structures include dikes, revetments.
breakwalls, seawalls, jetties, piers, retaining walls, boat docks,
groins, gabions, etc.. The Ohio Division of Geological Survey
has monitored the Ohio Lake Erie coastline to identify areas
subject to erosion. As part of this monitoring and mapping
effort, a comprehensive inventory of shore protection and
navigation structures was created in 2000. Historical shore
structure inventories along with aerial photographs and maps
were used to quantify changes in the amount of shore protection
that existed historically along the Ohio Lake Erie shoreline
by coastal county. Figure 7 illustrates how the percentage of
protected shoreline changed through time. As of 2000. more
than 75% of the Ohio Lake Erie coastline was protected (1>S%
in Lucas County near Toledo, Ohio). Most of these structures
were installed or upgraded within the past three decades in
response to historically higher water levels and more intense
coastal development.
&
1
o
(75
—
a;
.*--
o
C
•*->
e
Q-
•*-<
c
100
90
80
:
.
'
1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Time (Years)
Figure 7. Change in amount of shore protection along the
Ohio Lake Erie Coastline by coastal county, 1870 - 2000.
As of 2000, approximately 75% of the Ohio Lake coastline
was armored. Recent coastal mapping by the Ohio Division
of Geological Survey shows that these trends have
continued into the present in response to development (and
redevelopment) of Great Lakes coastal areas.
Source: Ohio Department of Natural Resources. Division of Geological Survey.
Recent recession-line mapping by the Ohio Division of
Geological Survey shows that there has been a significant reduction in measured erosion rates between 1990 and 2004. The
reduction in erosion rates is thought to be due. in part, to increases in amount of developed and protected shoreline in combination
with somewhat lower Lake Erie water levels since 1999. Continued coastal redevelopment and expanding suburban growth
along the coasts of all of the Great Lakes from urban centers suggest that these trends will continue into well into the future.
In 2007. an indicator called the Shoreline Alteration Index (SAI) was developed based on the Ohio shore structure inventory
and an assessment of biological compatibility of various types of shore protection structures in the Western basin of Lake Erie
(Livchak and Mackey 2007). Data from the Western basin of Lake Erie were used to test and validate the index. Shore protection
along Ohio's Western Lake Erie shoreline is generally effective with respect to erosion and flood control, but it is not biologically
or ecologically compatible (Fuller and Gerke 2005).
Livchak and Mackey (2007) proposed to use the ratio of protected to unprotected shoreline as a measure of physical alteration of
the land-water interface. In other words, a value of zero (0) would represent an unmodified natural shoreline and a value of one (1)
would represent a highly modified or 100% engineered shoreline.
Unprotected
100% Protected
NEARSHORE AREAS OF THE GREAT LAKES 2009
9
-------
For a given reach of shoreline, these values would then be multiplied by the ratio of structures that have poor biological compatibility,
where zero (0) would represent no biological or ecological impact (high compatibility) and one (1) would represent significant
biological or ecological impact (low compatibility).
High Biological Compatibility Low Biological Compatibility
0< >1
The resulting SAI would range from zero (0) representing an unaltered shoreline to one (1) representing a highly altered shoreline.
Within the context of this proposed indicator, alteration means impacted biological or ecological functions caused by modifications
to the shoreline and/or associated coastal processes.
Unaltered Highly Altered
0< >1
The advantage of this approach is that as structures are removed and/or modified to provide habitat enhancements, the indicator
will shift toward a more unaltered or natural state. Conversely, if the number and extent of biologically incompatible shoreline
structures increases, the indicator will shift toward a more altered state.
Simply put, the SAI is a measure of protected shoreline length that is physically and biologically unfavorable. The greater the SAI
value, the more altered the shoreline is. The SAI is scaleable to any reach length, and can be applied to present day and historical
data for comparison and trend analyses.
Clearly, Great Lakes shorelines can not be returned to the unprotected "natural" shorelines that existed before development
began in the 1800s. Given this reality, it is recommended that new shore protection structures along the coast be designed to be
more biologically compatible by mimicking and maintaining natural coastal processes. It is also recommended that management
strategies be developed to encourage rehabilitation of existing structures with "habitat" enhancements to restore natural habitat
functions and processes in nearshore zones. Moving toward biologically compatible shore protection structures is an essential
component to restoration of Great Lakes nearshore zones. More specific management recommendations are provided in Livchak
and Mackey (2007).
Non-Point Source Loadings and BMPs
For more than two decades, improvements in managing soil loss, nutrients, and non-point source loadings have been implemented
on agricultural landscapes. These best management practices (BMPs) are designed to improve agricultural efficiencies, retain soil
and nutrients, and protect water quality. BMPs can effectively change the hydrologic response of agricultural lands and minimize
harmful impacts to rivers, lakes, and the nearshore zones of the Great Lakes. Effective implementation of BMPs over large areas
can cause a considerable improvement in water quality and significantly reduce sediment, nutrient, and contaminant loadings
into the Great Lakes. One of the most successful BMPs is conservation tillage, where fields are not tilled between crop rotations
(no-till), or where tillage is minimized to leave plant residue on the soil surface to stabilize the soil surface and reduce erosion by
water. Conservation tillage has been actively promoted since the late 1980s and the acreage under conservation tillage has steadily
increased in the Great Lakes basin.
In northwest Ohio (a major source of loadings into Lake Erie), currently -55 to 60% of the bean acreage is no-till and -20 to
25% of the corn acreage is no-till in the Sandusky and Lower Maumee River watersheds (Figs. 8a and b). Based on these plots,
conservation tillage in these watersheds increased from 1996 to 2000, and then leveled off and/or declined slightly though 2004.
Natural Resources Conservation Service (NRCS) believes that these acreages have not changed significantly since 2004 (Steve
Davis, NRCS, personal communication). Agricultural land use in these watersheds is predominately row crop agriculture and is
focused on beans, corn, and winter wheat. Long-term trends in soil, nutrient, and contaminant loadings are described elsewhere
in this background paper. However, continued implementation and refinement of these BMPs is a critical component to protecting
and restoring Great Lakes nearshore zones.
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 10 —
-------
0)
05
CO
a
No-Till
Ridge & Mulch Till
Total
Soybeans
Year
80
0)
!? 70
p
O 60
c 50
O 40
*O 30
+••
g 20
^ No-Till
Ridge & Mulch Till
• Total
Corn
75 3
JD ^
I
c
I
Summary
Land use land cover changes in watersheds have
altered flow paths to tributaries, changing flow
regimes and dramatically increasing sediment
and nutrient loads, causing channel erosion
and instability, and degrading the quality of
tributary flows into the Great Lakes. Tributary
waters must flow through coastal margin and
nearshore habitats to reach the open lake, and
are therefore affected by anthropogenic actions
in the watersheds. Chemical contaminants.
nutrients, and fine-grained sediments have
adversely affected nearshore habitat structure and
ecosystem function. Even though steps have been
taken to slow the rate of degradation, continued
population growth and associated changes in land
use/landcover in Great Lakes watersheds will
continue cause further degradation of coastal
margin and nearshore habitats.
Acknowledgments
Author: Scudder D. Mackey. Ph.D. Habitat
Solutions NA. scudderw sdmackey.com
Information Sources
Apfelbaum. S.. Bell. J.. Roland. R.. Mackey.
S.D.. DePhilip. M.. Khoury. M.. and Hinz.
L. 2007. Identifying and valuing restoration
opportunities and resource improvements at
watershed and suhwutershed Scales. Final
Report. Grant £758. Great Lakes Protection
Fund. pp. 159.
Audi. R.. Taylor. J.. and Acevado. W. 2004.
L'rhan growth in American cities: Glimpses
nt I .V urbanization. U.S. Geological Survey
Circular 1252. U.S. Geological Survey. Sioux
Falls. SD.
Baron. J.S., Poff. N.L.. Angermeier. PL.. Dahm.
C.N.. Gleick. PH.. Hairston. N.G.. Jackson.
R.B.. Johnston. C.A.. Richter. B.D.. and
Stcinman. A.D. 2003. Sustaining healthy
freshwater systems. Issues in Ecology 10:1-16.
Center for Watershed Protection. 1994. The importance of imperviousness. Watershed Protection Techniques 1(3): 100-111.
Danz. N.P.. Niemi. G.J.. Regal. R.R.. Hollenhorst. T.. Johnson. L.B.. Hanowski. J.M.. Axler. R.. Ciborowski. J.J.H.. Hrabik. T..
Brady. V.J.. Kelly. J.R.. Bra/ncr. J.C.. Howe. R.W.. Johnston. C.A.. and Host. G.E. 2007. Integrated gradients of anthropogenic
stress in the U.S. Great Lakes basin. Environmental Management 39: 619-647
Environment Canada and U.S. Environmental Protection Agency. 2005. Stale of the Great Lukes :
-------
E. Wilke, G. Norwood, and A. Vincent. Detroit River-Western Lake Erie Basin Indicator Project, p. 86-90.
http://www.epa.gov/med/grosseile_site/indicators/sos-indicators.html
Mackey, S.D. 2005. Physical Integrity of the Great Lakes: Opportunities for Ecosystem Restoration: Report to the Great Lakes
Water Quality Board, International Joint Commission, Windsor, ON.
Niemi, G.J., Axler, R., Brady, V., Brazner, 1, Brown, T., Ciborowski, J.H., Danz, N., Hanowski, J.M., Hollenhorst, T., Howe,
R., Johnson, L.B., Johnston, C.A., Reavie, E., Simcik, M., and Swackhamer, D. 2006. Environmental indicators of the U.S.
Great Lakes coastal region. Report NRRI/TR-2006/11 to the U.S. Environmental Protection Agency STAR Program, ver.l.
Agreement R82-8675, Washington DC. pp. 121. http://glei.nrri.umn.edu/default/documents/GLEI_nnal_VersionII.pdf
Niemi, G. J., Kelly, J.R., and Danz, N.P. 2007. Environmental Indicators for the Coastal Region of the North American Great Lakes:
Introduction and Prospectus. J. Great Lakes Res. 33 (Special Issue 2):1-12.
Pastor, J., and Wolter, P.T. 2002. Mapping and Modeling Forest Change in a Boreal Landscape. In Proc. NASA LCLUC Science
Team Meeting, Washington D.C.,19-21 November.
Poff, N.L., Allan, J.D., Bain, M.B., Karr, J.R., Prestegaard, K.L, Richter, B.D., Sparks, R.E., and Stromberg, J.C. 1997. The natural
flow regime: a paradigm for river conservation and restoration. BioScience 47:769-784.
Richter, B.D., and Richter, H.E. 2000. Prescribing flood regimes to sustain riparian ecosystems along meandering rivers.
Conservation Biology 14:1467-1478.
Richter, B.D., Baumgartner, J.V., Braun, D.P., and Powell, J. 1998. A spatial assessment of hydrologic alteration within a river
network. Regulated Rivers 14:329-340.
Silk, L. 2005. Ground Surface Hardening, Indicator #7054. Indicator Progress Report. In: State of Great Lakes 2005. U.S. EPA
and Environment Canada, pp. 2.
U.S. Department of Agriculture, National Agricultural Statistics Service, Research and Development Division, Cropland Data
Layer. 1992-2007. http://www.nass.usda.gov/research/Cropland/SARSla.htm
Wolter, P.T., Johnston, C.A., and Niemi, G.J. 2006. Land use land cover change in the U.S. Great Lakes Basin 1992 to 2001. Journal
of Great Lakes Research, 32:607-628.
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 12 —
-------
Lake System
Superior
Huron
Michigan
Erie
Ontario
Lake St. Clair
Total
Coastal Ecoreaches'
S1,S2,S3a,S3b,S4a,S4b.S4c,S5a,S5b,
S6a, S6b,S6c.S7a,S7b,S7c,S7d,S7e,LS
HG1a,HG1b,HG1c,HG1d,HG2a,HG2b.
HG3,HG4a. HG4b, HG5,HG6,HG7a.
HG7b,HG7c,HG8a,HG9,HG10,LH
M1.M2a,M2b.M3,M4a,M4b,M5.M6a.
M6b,M6c,M7a,M7b,LM
E1,E2,E3.E4,E5,E6a,E6b,E7a E7b,
E7c,E7d.LE
OS1 ,OS2.OS3a.OS3b,OS4a,OS4b,
OS4cOS5,OS6,OS7,LO
SC1.SC2.SC3
Total
Coast (km)
6.479
11.376
2,478
2,687
3,969
1,314
28,303
Coastal
Area2 (ha)
583,485
790.156
381.267
247.864
357,322
70,457
2,430.551
= See Figure 1.
2 = Defined as 2 km inland from the coast and the area of all islands.
Source: Coastal Ecoreaches based on Reid el al. (1999)
3.0 Coastal Terrestrial Ecosystems
State of the Ecosystem
Introduction
The Great Lakes coast1 is over 28,300 km (17,585 mi)
in length - a distance greater than half the equatorial
circumference of the Earth - making it the longest
freshwater coast in the world (Table 1). Driven by
its close proximity to the world's largest freshwater
seas, the dynamic Great Lakes coastal terrestrial
zone has been a catalyst for species and ecosystem
diversity. Many of the terrestrial endemic species
in the Great Lakes basin have evolved in the last
10.000 years in response to this coastal influence, and
approximately 200 disjunct species persist due to the
unique conditions of the coastal environment (Henson
ei al. 2005. TNC 1999). A large number of globally
rare ecosystems have also developed in response to Table 1. Summary of Great Lakes Coastal Systems.
the special conditions of the Great Lakes coast. The
Great Lakes basin includes one of the most diverse
assemblages of ecological systems in the United States
and southern Canada (Cornier ct al. 2003. NatureSen c 200S). and over 25 globally rare vegetation communities that are restricted
to the Great Lakes coast have been documented (NatureServe 2008). Many of these communities are the focus ot'tliis report.
The Great Lakes coastal terrestrial zone is also a region under many pressures. No other part of the Great Lakes basin has the
same depth and diversity of human history. For millennia coastal ecosystems have attracted human settlement for their access to
transportation, natural resources, water and aesthetics. Today, the coastal terrestrial zone contains the largest concentrations of
urban, industrial and recreational land uses in the Great Lakes basin. New development in the basin continues to be concentrated
in coastal areas (Wolter a al. 2006). The actions taken in the next few decades may determine our effectiveness in conserving
many coastal terrestrial ecosystems of the Great Lakes.
The state of the coastal terrestrial systems is inextricably connected to the health of the lakes, a linkage that has been well
documented in terrestrial riverine ecosystems, but is just being understood in large lake systems. Development of the shorelines
of freshwater lakes can have a significant impact on nearshore aquatic habitats, nutrient cycles, physical processes and species
assemblages (Scheuerell & Schindler 2004). including fish populations and richness (Brazner 1997). Within the Great Lakes, the
health of the coastal terrestrial ecosystems is linked with the health and diversity of the nearshore waters. Fish and zooplankton
communities are generally lower in nearshore waters adjacent to developed coasts (Goforth & Carman 2005). especially as they
relate to changes in substrate composition and stability. Shoreline development and modifications alter nearshore substrate processes
and may facilitate invasions of nearshore aquatic invasive species (Meadows ct al. 2005). and degree of shoreline development may
provide a terrestrial-based indicator of the relative integrity of nearshore aquatic systems. This linkage highlights the importance
of coastal conservation. Protection of coastal terrestrial ecosystems conserves globally unique species and communities and
supports the maintenance of nearshore processes and aquatic biodiversity.
Scope and Purpose of this Report
This report provides an update of the original SOLEC 1996 chapter on coastal terrestrial ecosystems. Lami hy the Lakes (Reid and
Holland 1997). and has two primary objectives:
• To update baseline information on the coastal terrestrial ecosystems.
• To identify trends in these systems, and answer the question: ll'luit has changed since 1996?
1 Includes mainland and islands of the Greal Lakc>.
NEARSHORE AREAS OF THE GREAT LAKES 2009
13
-------
To address the first objective, this report
has included the assembly and analysis
of the best available spatial data on Great
Lakes coastal terrestrial ecosystems.
much of which was not available for the
original report (Appendices A and B).
This includes coastal mapping for Canada
(Environment Canada. Ontario Ministry of
Natural Resources) and the U.S. (National
Oceanic and Atmospheric Administration).
and classifications and descriptions of
coastal terrestrial ecosystems from the
Great Lakes region (NatureServe 2008).
Ontario and U.S. Great Lake states - this
included element occurrences (EOs) of
coastal terrestrial vegetation communities.
The taxonomy of some of the 1996 coastal Table 2. Summary of Coastal Terrestrial Ecosystems, Cross-walked with SOLEC
terrestrial ecosystems has been changed to
reflect the names of Great Lakes ecological systems (NatureServe 2008). and two ecosystems were added (Table 2). Great Lakes
Islands, originally included in the 1996 report, now have a separate SOLEC indicator report (#8129) and are not addressed in this
report. Coastal wetlands and aquatic nearshore habitats are being covered in other reports for SOLEC 2008.
This project established a data-driven baseline of the location and extent of these coastal terrestrial ecosystems. Results of this
analysis were generated for each of the coastal ecoreaches in the Great Lakes (Fig. 1). Boundaries of the coastal ecoreaches are
based on Reid ci ul. (1999). Five additional coastal ecoreaches were created and used in the analysis to include offshore islands.
Coastal Terrestrial Ecosystems
Addressed in this Report
1. Great Lakes Sand Beaches
2. Great Lakes Foredunes
3. Coastal Back Dune Complexes
4. Bedrock Shores
5. Cobble Beaches
6. Shoreline Cliffs
7. Shoreline Bluffs
8. Lakeplain Prairies
9. Arctic-Alpine Disjunct Communities
10. Atlantic Coastal Plain Disjunct Communities
11. Rich Coastal Fens
12. Shoreline Alvars
13. Coastal Rock Barrens
14. Great Lakes Coastal Forests
SOLEC 1996 Name
Sand Beaches
Sand Dunes
Sand Barrens
Bedrock and Cobble Beaches
Bedrock and Cobble Beaches
Limestone Cliffs and Talus Slopes
Unconsolidated Shoreline Bluffs
Lakeplain Prairies
Arctic-Alpine Disjunct Communities
Atlantic Coastal Plain Disjunct Communities
New
Shoreline Alvars
Coastal Gneissic Rocklands
New
N
Figure 1. Great Lakes Coastal Units.
Sources: Nature Conservancy of Canada - Ontario Region (2007), OMNR (2007), ESRI Data & Maps (2006), Natural Resources Canada, Canada
Centre for Cadastral Management (2003). NOAA. Coastal Services Center (2002). and U.S EPA (2000).
NEARSHORE AREAS OF THE GREAT LAKES 2009
14
-------
The second objective of the report is to identify the trends and pressures on the coastal terrestrial ecosystems based on a literature
review. In addition, an analysis to quantify the condition of each coastal unit based on an assessment of shoreline alteration and
land cover is included. This analysis provides a general index of the health of coastal terrestrial ecosystems around the basin.
Results
Ecosystem Summary, Distribution, Status and Trends
The following section provides a summary for each of the 14 coastal terrestrial ecosystems identified in Table 2. For each coastal
terrestrial ecosystem the global status of the ecosystem (based on status ranks of the component vegetation communities -
Appendix B) and general background information on the composition and functions of the ecosystem are provided. A table on
each coastal terrestrial ecosystem provides a summary of its distribution, status and trends.
3.1 Great Lakes Sand Beaches
Global Status: Vulnerable
Related Coastal Terrestrial Ecosystems: Great Lakes Foredunes, Coastal Back Dune Complexes, Cobble Beaches
SOLEC1996: Sand Beaches
Background: Great Lakes Sand Beaches include the active beach area below the high watermark. They have specific physical
requirements and are restricted to a narrow zone along the Great Lakes. They are very active systems, formed when waves and
wind deposit sand that has eroded from other places onto an exposed shoreline. Sand beaches are dynamic, and sand may be
washed away with erosive storms or ice transport, or be blown inland to form sand dunes - they can also migrate with changing
water levels. These are high energy environments and tend to be very open with have low plant richness and cover and little soil
development (Kost et al. 2007). Up-rooted trees or surficial organic matter accumulation may allow for changes in the sediment or
vegetation characteristic of the beach, but these changes are usually temporary.
Distribution, Status and Trends - Great Lakes Sand Beaches
Lake System
Total/ % of Coast
Superior
618 km/9.5%
Michigan
151 5 km/61.1%
Huron
709 km/6.2%
St. Clair
16 km/1. 2%
Erie
387 km/14.4%
Ontario
139 km/3.5%
Coastal Reaches1
S1,S2,S3a,S3b,S4a,S4c,S5a,S5b,S6a,S6b,S6c,S7a,S7b,
S7d,S7e,LS
M1,M2a,M2b,M3,M4a,M4b,M5,M6a,M6b,M6c,M7a,M7b,LM
HG1a,HG1b,HG1c,HG1d,HG2a,HG2b,HG3,HG4a,HG4b,
HG5,HG6,HG7a,HG7b,HG7c,HG8a,HG9,HG10
SC1.SC2.SC3
E1,E2,E3,E4,E5,E6a,E6b,E7a,E7b,E7c,E7d, LE
OS1,OS2,OS3a,OS3b,OS4a,OS4b,OS4c,OS5,OS6,OS7
Key Coastal Reaches2
S2,S7e
M1,M2a,M3,M6b,M7b
HG4a,HG5
SC1,SC2,SC3 (primarily in SC2)
E2,E3,E4,E5,E6a,E7d
OS1 ,OS3a,OS4a,OS5,OS5,OS6,OS7
Status/ Trend
Good/ Unchanging
Mixed/ Unchanging
Mixed/ Unchanging
Poor/ Undetermined
Mixed/ Unchanging
Mixed/ Unchanging
1 = Based on coastal mapping and element occurrence (EO) data. Boldface denotes coastal reach with documented EOs. Includes beach and dune EOs.
2 = Key Coastal Reaches include >10% of the total extent of the ecosystem in the context of each Great Lake.
Approximately 3,385 km (2,100 mi) of sand beaches occur on the Great Lakes. Sand beaches characterize much of the Lake
Michigan shoreline (especially on the eastern shore), and large examples also occur on Lake Erie sand spits, Nottawasaga Bay
(Huron), eastern Lake Superior and eastern Lake Ontario. Great Lakes Sand Beaches are considered globally rare by NatureServe
with fewer than 100 occurrences and are considered rare in Ontario and all U.S. states (NatureServe 2008). Among the documented
occurrences, the average size is approximately 10 ha (24.7 acres) (NatureServe 2008). Elements of this community can occur in
association with other coastal ecosystems including dunes and eroding bluffs. Only one type of sand beach has been identified
(NatureServe 2008) (Appendix A); this community is characterized by sea rocket (Cakile sp.) in association with American
beachgrass (Ammophila breviligulatd). Sand beach ecosystems are intricately linked with dunes and coastal barrens, and typically
form the first interface between dune and the lake.
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 15 —
-------
Many key sand beaches are in existing parks and protected areas, and most beaches are not directly impacted by site development,
although shoreline hardening and structures that alter nearshore sand movement can have impacts over large areas of the coast
by reducing sand deposition. Most beaches in protected areas are subject to high levels of recreational use. Stewardship of these
sites is improving, although enhancements could be made. These include reduced vehicle use and beach "cleaning" that removes
organic matter.
3.2 Great Lakes Foredunes
Global Status: Vulnerable - Apparently Secure
Related Coastal Terrestrial Ecosystems: Great Lakes Sand Beaches, Coastal Back Dune Complexes
SOLEC1996: Sand Dune
Background: Great Lakes Foredunes are defined as open stabilized foredunes, and are formed along open sandy shores with
consistent winds that transport the sand inshore (Reid and Holland 1997). Dune formation is a dynamic process that is linked to
erosion and wind deposition, including initial dune formation during the recession of ancient lakes, erosion of the remaining bluffs
and deposition of this sediment onto beaches where it is transported into dunes (Kost et al. 2007). Foredunes are formed when
vegetation such as American beachgrass causes wind to drop sand, which accumulates and is then colonized by grasses such as
prairie sandreed (Calamovilfa longifolia) and little bluestem (Schizachyrium scoparium) and trees/shrubs such as eastern
cottonwood {Populus deltoides), balsam poplar (Populus balsamiferd), sand cherry (Prunus pumila) and willow (Salix sp.) species
(Reid and Holland 1997). Component plant communities vary from sparsely vegetated dunes to communities dominated by
grasses, shrubs, and trees, depending on the degree of sand deposition, sand erosion, and distance from the lake. Dune systems are
very important for the biodiversity of the Great Lakes region. Less than 40% of Great Lakes dune plant species also grow in
maritime dunes (NatureServe 2008). Forested dunes and associated barrens and wetlands associated with secondary dunes
formations are treated under Coastal Sand Barrens and Forested Dunes. Great Lakes Foredunes always occur in association with
sand beaches.
Distribution, Status and Trends - Great Lakes Foredunes
Lake System
Superior
Michigan
Huron
St. Clair
Erie
Ontario
Coastal Reaches*
S2.S3a,S3b,S4c,S6a,S6c,S7e
M1,M2b,M3,M4a,M4b,M5,M6a,M6b,M6,M7a,M7b,LM
HG2b,HG3,HG4a,HG7c,HG10
Does not occur.
E3,E5,E6a,E6b,E7b,E7d,LE
OS3b,OS5,OS7
Key Coastal Reaches1
S3a,S3b,S6a,S6b
M1,M2b,M6b,M7a
HG10
-
E6a
OS7
Status/ Trend
Good/ Unchanging
Mixed/ Improving
Mixed/ Improving
-
Mixed/ Improving
Mixed/ Improving
1 = Based on element occurrence (EO) data.
2 = Key Coastal Reaches include over five documented EOs, or the highest number of EOs for the lake.
Approximately 30,000 ha (74,000 acres) of sand dunes (including Back Dune Complexes) can be found along the Great Lakes
coastline (EC and USEPA 2007) - this is the world's largest collection of freshwater sand dunes. Dunes occur on all the Lakes,
but are most common on the southeastern shore of Lake Superior, eastern Lake Michigan, southern Lake Huron and eastern Lake
Ontario. Approximately 2-3% of the Lake Huron coast includes dunes (Peach, personal communication).
Six foredune communities have been identified from the Great Lakes coast, most of which are globally rare (NatureServe 2008)
(Appendix A). The most common and widespread dune community is Great Lakes Beachgrass Dune. Characteristic species
include American beachgrass, prairie sandreed, and in stabilized areas little bluestem. This community is closely related to the
shrub dominated dune systems including common juniper (Juniperus communis) and sand cherry. The Northern Great Lakes
Dune Grassland is more poorly documented, and known only from Lake Superior. Cottonwood Dune is the only tree community
that occurs on stabilized foredunes. This community occurs in dune fields and on the most stable dune ridges in the southern Great
Lakes region and is very rare globally. While there has historically been a significant decline in occurrences due to residential
development, many of the remaining examples have been identified and protected. However, at some of these sites, including
those in parks, inappropriate uses continue to threaten this fragile ecosystem (Bakowsky 1998a), although there are increasing
examples of dune stewardship on public and private lands that is resulting in the rebuilding of foredunes (Featherstone, persona)
communication). Dune awareness and stewardship programs have been initiated by the Michigan Natural Features Inventory ana
the Lake Huron Centre for Coastal Conservation.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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3.3 Coastal Back Dune Complexes
Global Status: Vulnerable
Related Coastal Terrestrial Ecosystems: Great Lakes Foredunes, Great Lakes Coastal Forests
SOLEC1996: included in Sand Barrens
Background: This ecosystem includes a complex of forests, wetlands and barrens that are associated with stabilized back dunes.
This report only includes those dunes that are part of the present day lakeshore. In some cases these communities can extend inland
for several kilometres and show evidence of past lake levels (e.g. Oak Openings in Ohio, Indiana Dunes National Lakeshore). This
ecosystem does not include open sandy areas that are not related to the coast. Coastal Back Dune Complexes often occur as a series
of alternating ridges and swales. The ridges typically support dry forests and the swales between the ridges are often close enough
to the water table to support wetland communities. The composition and structure of this ecosystem is highly variable around the
basin. For example, six major subtypes of Great Lakes Dune and Swale have been described for Michigan based on location and
dune structure.
Distribution, Status and Trends - Coastal Back Dune Complexes
Lake System
Superior
Michigan
Huron
St. Clair
Erie
Ontario
Coastaf Reaches'
S2, S5b, S6a, S6c, S7a, S7b, S7c, S7d, S7e
M1, M2a, M2b, M3, M4a, M4b, M5, M6a, M6b, M6c, M7a, M7b
HG2a, HG3, HG4a, HG5, HG6, LH
Does not occur.
E7c
No documented element occurrences, but known to occur
(Bonannoefa/. 1998).
Key Coastal Reaches2
S5b
M1,M2b,M4b,M5,M6b,M6c
HG3,HG4a,
-
E7c
-
Status/ Trend
Mixed/ Deteriorating
Mixed/ Deteriorating
Mixed/ Deteriorating
-
Good/ Unchanging
-
1 = Based on element occurrence (EO) data. Includes EOs for Wooded Dunes and Swale Complex, Beach Ridge, Interdunal Wetland and Great Lakes Barren.
Prairie and savanna EOs near coast are also included.
2 = Key Coastal Reaches include 5+ documented EOs.
All four documented Great Lakes Forested Dunes, Barrens & Swales vegetation communities are globally rare (NarureServe
2008) (Appendix A). 1) Wooded Dune and Swale Complexes have been documented at nearly 100 occurrences throughout the
region and often occur where post-glacial streams enter an embayment and provide a sand source. Dune ridges in the northern
Great Lakes typically include jack pine (Pinus banksiand), red pine (Pinus resinosa), white pine (Pinus strobus), common juniper,
bearberry (Arctostaphylos sp.) and creeping juniper (Juniperus horizontalis). Those in the southern Great Lakes are characterized
by eastern cottonwood, black oak (Quercus velutind) and white pine. Occurrences in eastern Lake Ontario are dominated by red
oak (Quercus rubra) and red maple (Acer rubrum) (Bonanno et al. 1998). Swales include open wetlands or swamps. Complexes
located in embayments protected from winds tend to be formed entirely of very low ridges dominated by wetland vegetation (e.g.
parts of Point Pelee National Park). This ecosystem has also been classified according to its upland and wetland components. 2)
Interdunal Wetlands are found in the southern Great Lakes and in parts of northern Lake Michigan; 36 occurrences have been
documented, totaling 539 ha (1,132 acres). 3) Great Lakes Dune Pine Forest is found on dune systems of Lake Michigan and
Lake Huron where it is a component of a Wooded Dune and Swale Complex. It is restricted to drier, sandy soils on dune tops or
ridges. This forest system is closely associated with 4) Great Lakes Pine Barrens, a coniferous savanna characterized by scattered
trees and low shrubs. This ecosystem is not tracked in Ontario, although many occurrences exist (e.g. Pinery and Wasaga Beach
Provincial Parks).
Unlike the more active sand beaches and dunes that typically occur between this ecosystem and the lake, forested dunes and
swales are more susceptible to being developed. All Great Lakes Forested Dunes, Barrens and Swales are considered to be globally
rare and many sites have been degraded. High quality occurrences are found in Lake Superior on the Apostle Islands National
Park. This ecosystem has been poorly documented in Ontario and is not specifically tracked.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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3.4 Bedrock Shores
Global Status: Vulnerable - Secure (variable by community type)
Related Coastal Terrestrial Ecosystems: Cobble Beaches, Shoreline Cliffs, Arctic-Alpine Disjunct Communities, Coastal Fens,
Shoreline Alvars, Coastal Rock Barrens, Coastal Forests
SOLEC1996: Bedrock Beach/Cobble Beach (this system was divided by SOLEC in 1998; Reid et al. 1999)
Background: Bedrock shores include basic and acidic exposed bedrock that is < 1 m (3.28 ft) in height. These shores can range
from bare bedrock to bedrock overlaid with cobble. The bedrock may be horizontal or tilted, rounded or blocky, and may include
ledges. The leading edge of the shoreline may be heavily impacted by wave action and winter ice movement and typically has little
or no vegetation (Kost et al. 2007). Narrow areas of exposed rock at less than a meter above the lake are generally moist and
support mosses and liverworts, and scattered vascular plants. Vegetation cover and height increases inland. Above the zone of
wave and ice influence, woody vegetation becomes dominant. These dry systems are often the edge of other ecosystems including
alvars and acidic rock barrens (Reid and Holland 1997, Kost et al. 2007).
Distribution, Status and Trends - Bedrock Shores
Lake System
Total/ % of Coast
Superior
1863 km/28.7%
Michigan
270 km/10.9%
Huron
2953 km/26.0%
St. Clair
24 km/1.8%
Erie
221 km/8.2%
Ontario
655 km/16.5%
Coastal Reaches1
S1,S2,S3a,S3b,S4a,S4b,S4c,S5a,S5b,S6b,S6c,S7a,S7b,S7c,S7d,
S7.LS
M1,M2a,M2b,M3.M7a,LM
HG1a,HG1b,HG1d,HG2a,HG2b,HG3,HG4a,HG4b,
HG7a,HG7b,HG7c,HG8a,HG9,HG10
SC1
E1 ,E2,E6a,E6b,E7a,E7b,E7d
OS1 ,OS2,OS3a,OS3b,OS4a,OS4b,OS4c OS5,OS6,OS7
Key Coastal Reaches2
S4b,S5b,S6c
M2a,M2b,M7a,LM
HG2a,HG2b,HG3,HG8a,HG9
SC1
E1,E2,E6b,E7d
OS1,OS2,OS3a,OS3b
Status/ Trend
Good/ Improving
Mixed/ Deteriorating
Good/ Improving
Poor/ Unchanging
Mixed/ Deteriorating
Mixed/ Deteriorating
1 = Based on coastal mapping and element occurrence (EO) data. Boldface denotes coastal reach with documented EOs.
2 = Key Coastal Reaches include >10% of the total extent of the ecosystem in the context of each Great Lake.
Bedrock shores are classified by Alkaline and Non-Alkaline types (NatureServe 2008) (Appendix A). Alkaline types may consist
of alkaline igneous, metamorphic, or sedimentary rocks and three types have been documented. The most common is 1) Great
Lakes Basalt - Conglomerate Bedrock Shore along Lake Superior that consists of basalts, volcanic conglomerates, and localized
rhyolites. This ecosystem is associated with Arctic-Alpine Disjunct Communities. 2) Great Lakes Sandstone Bedrock Shore is
restricted to small areas of Lake Superior and Lake Huron, typically in association with sandstone cliffs. 3) Great Lakes Limestone-
Dolostone Bedrock Shore occurs in an arch from the southern Bruce Peninsula to Drummond Island and the Door Peninsula, with
scattered occurrences in the Lake Huron Shore of Michigan's lower peninsula, Lake Erie and eastern Lake Ontario.
Non-Alkaline Bedrock shore is comprised on Great Lakes Granite - Metamorphic Bedrock Shore characteristic of the Canadian
Shield. This sparsely vegetated shore community is found along Lake Superior, Lake Huron and a very small portion of Lake
Ontario.
Almost 6,000 km (3,728 mi) of bedrock shore occurs in the Great Lakes, primarily in the north. Sandstone and Limestone -
Dolostone Bedrock Shores are considered to be globally rare. Large areas of Great Lakes Basalt - Conglomerate and Granite
- Metamorphic Bedrock Shores are protected along Lake Huron and Lake Superior (e.g. the newly created Georgian Bay Shoreline
and Islands Conservation Reserve at 17,828 ha (44,054 acres).
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 18 —
-------
3.5 Cobble Beaches
Global Status: Vulnerable - Secure (variable by community type)
Related Coastal Terrestrial Ecosystems: Great Lakes Sand Beaches, Bedrock Shores, Shoreline Cliffs, Coastal Fens, Shoreline
Alvars, Coastal Rock Barrens, Coastal Forests
SOLEC1996: Bedrock Beach/ Cobble Beach (this system was split by SOLEC in 1998; Reidet al. 1999)
Background: Cobble beaches are highly variable and can range from small cobbles to large boulders. This ecosystem is typically
a dynamic environment of wind and, more significantly, waves, ice and changing water levels that can disturb the beach habitat
and reconfigure the cobble and sediment. Vegetation is typically sparse, but also variable depending on exposure and the amount
of fine sediments between the cobble (EC and U.S. EPA 2005). On storm beaches, cobbles can accumulate to a depth of several
meters, and in these conditions, vegetation is often absent. Beaches with shallow accumulations of gravel and small cobble can
have very rich plant communities, especially when the spaces between the cobble is filled with sand (Kost et al. 2007, Albert and
Kost2007).
Distribution, Status and Trends - Cobble Beaches
Lake System
Total/ % of Coast
Superior
911 km/14.1%
Michigan
12 km/0.5%
Huron
1449 km/12.7%
St. Clair
3 km/0.2%
Erie
48 km/1 .8%
Ontario
297 km/7.5%
Coastal Reaches1
S1,S2,S3a,S3b,S4a,S4c,S5a,S5b,S6c,S7a,S7b,S7c,LS
M1,M2a,M2b,M4b,M7a
HG1a,HG1b,HG1c,HG1d,HG2a,HG2b,HG3,HG4a,HG4b,HG5,HG7a,HG7
b,HG7c,HG10,HG8a,HG9
SC1
E1,E2,E3,E4,E6b,E7b,E7c,E7d
OS1 ,OS2,OS3a,OS3b,OS4a,OS4b,OS4c OSS
Key Coastal Reaches2
S1,S3b,S4a,S4c
M2a,M2b,M7a
HG2a,HG7a,HG7b,HG8a
SC1
E2,E6b,E7b,E7d
OS1,OS3a,OS4b
Status/ Trend
Good/ Improving
Mixed/ Deteriorating
Good/ Improving
Poor/ Unchanging
Mixed/ Unchanging
Mixed/ Deteriorating
1 = Based on coastal mapping and element occurrence (EO) data. Boldface denotes coastal reach with documented EOs.
2 = Key Coastal Reaches include >10% of the total extent of the ecosystem in the context of each Great Lake.
Three cobble beach types have been described around the Great Lakes (NatureServe 2008) (Appendix A): 1) Limestone Cobble -
Gravel Great Lakes Shores occur in central Lake Huron along the Niagara Escarpment and in Lake Ontario. While this type can
be locally common, it does have restricted range. 2) Basalt - Diabase Cobble - Gravel Great Lakes shore type is common along
the northern Great Lakes. 3) Non-alkaline Cobble - Gravel Great Lakes shore type is found along the shores of northern Great
Lakes in the United States and Canada.
Limestone Cobble - Gravel and Non-alkaline Cobble - Gravel Great Lakes communities are ranked as globally rare. However,
Non-alkaline Cobble - Gravel Great Lakes type is underreported in Ontario, and may be more common. Large areas of this system
and Basalt - Diabase Cobble - Gravel Great Lakes shore type have been protected in Ontario in the last decade on Lake Superior
and Huron.
3.6 Shoreline Cliffs
Global Status: Apparently Secure - Secure (variable by community type)
Related Coastal Terrestrial Ecosystems: Bedrock Shores, Cobble Beaches, Coastal Rock Barrens, Coastal Forests
SOLEC 1996: Limestone Cliffs/ Talus Slopes (scope was extended to include all cliff types)
Background: Shoreline cliffs are vertical or near vertical embankments of bedrock that occur along the present-day shore and are
shaped by coastal processes including erosion and wave spray. Cliffs can generally be divided into three vegetation zones: ridge-
top forest, cliff face and talus (Kost et al. 2007). Most cliff faces are subject to extreme temperature fluctuations, and support
scattered herbs and ferns in fissures, and stunted trees along ledges (Reid and Holland 1997). Talus slopes occur at the bottom of
cliffs and are formed by large blocks of rock that have broken away from cliff faces (Reid and Holland 1997, Kost et al. 2007).
Talus slopes tend to be unvegetated in the wave-wash area, with increasing herbs, then shrubs, then mixed forests as distance from
the shoreline increases (Reid and Holland 1997). Cliffs can include many unique formations. In Michigan cliffs range from only
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 19 —
-------
3-6 m (9.8-19.7 ft) to over 60 m (197 ft) tall (Kost et al. 2007). Along the Niagara Escarpment in the Great Lakes region, the cliff
can reach well over 100 m (328 ft) above the shoreline and include sea caves, karst caves, over-hanging cliffs and "flowerpot"
islands (Reid and Holland 1997, Kost et al. 2007).
Distribution, Status and Trends - Shoreline Cliffs
Lake System
Total/ % of Coast
Superior
1390 km/21 .5%
Michigan
45 km/1 .8%
Huron
2923 km/25.7%
St. Clair
Erie
118 km/4.4%
Ontario
226 km/5.7%
Coastal Reaches'
S1,S2,S3a,S3b,S4a,S4c,S5b,S6a,S6b,S6c,S7a,S7b,S7c,S7d,S7e,LS
M2a,M2b,M3,LM
HG2a,HG2b,HG4b,HG7a,HG7b,HG8a,HG9,HG10
Does not occur.
E1,E6a,E6b \
OS1 ,OS2,OS3a,OS4a,OS5
Key Coastal Reaches2
S3a,S3b,S4c
M2b,M3,LM
HG8a,HG9
-
E1,E6a
OS2
Status/ Trend
Good/ Improving
Mixed/ Unchanging
Mixed/ Improving
-
Mixed/ Unchanging
Mixed/ Unchanging
1 = Based on coastal mapping and element occurrence (EO) data. Boldface denotes coastal reach with documented EOs.
2 = Key Coastal Reaches include >10% of the total extent of the ecosystem in the context of each Great Lake. Some U.S. areas classified as cliffs appear to be bluffs
(e.g. along lower Lake Michigan), and were re-classified as bluff based on physiographic descriptions and expert opinion. Some U.S. cliffs may be low cliffs (i.e. <1m
(3.3 ft)), which in Ontario were classified as bedrock shore.
Four cliff communities have been documented in the Great Lakes region (NatureServe 2008) (Appendix A): 1) Great Lakes Shore
Limestone - Dolostone Cliff community type occurs along the Bruce Peninsula, Manitoulin Island and the Niagara Gorge; 2)
Basalt - Diabase Cliff community type is found along Lake Superior; 3) Granite - Metamorphic Cliff community type is found
along the northern shoreline of Lake Superior and Huron; 4) Sandstone Cliff is found in the northern Great Lakes shorelines of the
United States and Canada. The substrate is Precambrian sandstone, which in Michigan is exposed along the southern shoreline of
Lake Superior.
Cliffs are a relatively common ecosystem along the Great Lakes, and include over 3,385 km (2,103 mi) of the coast. They are most
abundant in the northern lakes. While none of the documented community types are listed as globally rare, several types have not
been ranked. Limestone - dolostone and sandstone based communities appear to be the least common.
3.7 Shoreline Bluffs
Global Status: Apparently Secure (system has not been ranked)
Related Coastal Terrestrial Ecosystems: Great Lakes Sand Beaches, Coastal Forests
SOLEC1996: Unconsolidated Shore Bluff
Background: Shoreline Bluffs are comprised of vmconsolidated soil materials, including clay, till, silt, sand, gravel and loam.
Bluffs tend to be relatively low in height (2-20 m (6.6-66 ft)), but in some areas can reach heights of up to 110 m (361 ft) (Reid
and Holland 1997, NHIC 2008). Bluffs can be gently sloping to nearly vertical and can include a variety of topography including
gullies and pinnacles (e.g. Chimney Bluffs along southern Lake Ontario). Steep slopes on bluffs are often bare and completely
devoid of vegetation. The tops of bluffs and gently sloping bluff systems are often forested. Pioneer shrubs can be found in unstable
populations along actively eroding bluffs. Bluff nesting birds such as bank swallows (Riparia riparia) and belted kingfishers
(Ceryle alycon) use these systems.
Actively eroding bluffs are a source of sediments for beaches and are a key component in nearshore sediment processes. Some
bluffs are protected by beach systems at their toe, which can reduce erosion (Reid and Holland 1997). Shore bluffs often contain
seepage areas which can lead to the creation of wetland systems, including the unique hanging fens found in the shore bluffs at
Bond Head on Lake Ontario in Ontario.
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 20 —
-------
Distribution, Status and Trends - Shoreline Bluffs
Lake System
Total/ % of Coast
Superior
108 km/1 .7%
Michigan
354 km/14.2%
Huron
118 km/1.0%
St. Clair
53 km/4.0%
Erie
337 km/12.5%
Ontario
324 km/8.2%
Coastal Reaches1
S1,S2,S3b,S4c,S6a,S6c,S7a,S7b,S7c,S7d
M4a, M4b, M5,M6a,M6b,M6c,M7a,M7b
HG1a,HG1b,HG1c,HG4a,HG4b,HG5,HG7a,HG7b
SC1,SC2,SC3
E1,E2,E3,E4,E5,E6a,E6b,E7a,E7b,E7c,E7d
OS1 ,OS3a,OS3b,OS4a,OS4b,OS5, OS6.OS7
Key Coastal Reaches2
S1,S2,S7a
M4a
HG1b,HG1c,HG4a,HG5
SC3
E1,E4,E6a
OS1,OS4a,OS4b
Status/ Trend
Mixed/ Unchanging
Mixed/ Deteriorating
Mixed/ Unchanging
Mixed/ Deteriorating
Mixed/ Deteriorating
Mixed/ Deteriorating
1 = Based on coastal mapping and element occurrence (EO) data. Boldface denotes coastal reach with documented EOs.
2 = Key Coastal Reaches include >10% of the total extent of the ecosystem in the context of each Great Lake. Some U.S. areas classified as cliffs appear to be bluffs
(e.g. along lower Lake Michigan), and were re-classified as bluff based on physiographic descriptions and expert opinion.
Bluffs have been poorly described around the Great Lakes, with few documented element occurrences and only one described
type: Clay Shoreline Bluffs (NatureServe 2008) (Appendix A).
Shoreline bluffs occur along over 1,200 km (746 mi) of the coast, and can be found throughout the Great Lakes basin south of the
Canadian Shield. Shoreline Bluffs have not been ranked, but given their very limited distribution, they are likely globally rare.
3.8 Lakeplain Prairies
Global Status: Critically Imperiled
Related Coastal Terrestrial Ecosystems: Coastal Forests
SOLEC1996: Lakeplain Prairies
Background: Lakeplain prairies occur on glacial lakeplains in the southern Great Lakes. These lakeplain areas consist of rich and
deep soil - generally a deep layer (1-3 m (3.3-9.8 ft)) of permeable sand with underlying heavy clay which excludes the water table
and allows for seasonal flooding and drought (Kost et al. 2007). Flooding is common in the spring, often followed by dry conditions
in the summer and fall. This flood-drought cycle excludes many trees and shrubs. Flooding in combination with frequent low
intensity fires allows the prairie to retain open conditions (Kost et al. 2007).
Distribution, Status and Trends - Lakeplain Prairies
Lake System
Superior
Michigan
Huron
St. Clair
Erie
Ontario
Coastal Reaches'
Does not occur.
M3,M4b,M5,M6b
HG6
SC2
E5
Does not occur.
Key Coastal Reaches2
-
M4b
HG6
SC2
E5
-
Status/ Trend
-
Mixed/ Unchanging
Mixed/ Unchanging
Mixed/ Unchanging
Mixed/ Deteriorating
-
1 = Based on element occurrence (EO) data.
2 = Key Coastal Reaches include 5+ documented EOs, or the highest number of EOs for the lake.
Four Lakeplain Prairie vegetation communities have been documented (NatureServe 2008) (Appendix A). While some wet-mesic
prairies extend inland, these four types are generally associated with coastal regions of the Great Lakes: 1) Lakeplain Mesic Oak
Woodland and 2) Lakeplain Wet-Mesic Oak Opening are characterized by scattered oaks on moist soils; 3) Lakeplain Wet-Mesic
Prairie are typically more open; 4) Lakeplain Wet Prairie is dominated by herbaceous cover including tall grasses and rich forb
assemblages. Wetter sites are characterized by Lakeplain Wet Prairie and dominated by Prairie Cordgrass, Canada Bluejoint and
sedges.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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-------
This ecosystem has a very limited global range, and is restricted to the southern portion of Lake Michigan and a narrow corridor
from southern Lake Huron to Western Lake Erie. Most lakeplain prairies (and other tallgrass prairies in North America) were
converted to agricultural areas in the 1800s, and only 1% of the original range remains today (Reid and Holland 1997). In Michigan
approximately 0.5% of the original prairie present at the time of settlement remains (Comer et al. 1995). The St. Clair Clay
Plains in Ontario once had over 35,000 ha (86,487 acres) of lakeplain prairie - today less than 2% remains (primarily on Walpole
Island) (Tallgrass Ontario and NCC 2008). This ecosystem formerly occupied sites that are now urban and/or agricultural - areas
around Chicago, Windsor and Detroit were probably dominated by lakeplain prairies - but are now heavily converted and few
lakeplain prairie sites remain. Many of the remaining sites have been degraded due to alteration to groundwater hydrology and
fire suppression, permitting increased dominance by woody species. There have been some recent improvements with bettei
understanding, stewardship, land owner outreach and land securement (Cuthrell et al. 2000).
3.9 Arctic-Alpine Disjunct Communities
Global Status: Undetermined, probably Vulnerable
Related Coastal Terrestrial Ecosystems: Bedrock Shores, Shoreline Cliffs (Basalt types)
SOLEC1996: Arctic - Alpine Disjunct Communities
Background: Arctic - Alpine Disjunct Communities occur in Lake Superior, in both Ontario and Minnesota. Populations of
disjunct species have been noted from other locations, but communities are restricted to the cool shores of Lake Superior. These
communities are relicts following the last ice age, and are found on islands, cliff, talus and other coastal habitats that support cold
micro-climates. As the glaciers receded, vegetation that occurred along the ice margin either disappeared or followed the ice
margin northward, to be replaced in the Lake Superior region by boreal forest. Only along the colder-than-normal micro-climates
adjacent to the lake (and a few other specialized locations such as glaciere talus and some open cliff rims) did the conditions persist
for which these species are adapted (Bakowsky 1998b). Vegetation is sparse and bare rock dominates. The richest sites usually
exhibit the greatest diversity of physical structure, including crevices, rock pools, boulder fields and shore platforms. Few arctic
- alpine disjunct animal species exist, but several species of disjunct snails including those in the Vertigo genus have been noted
(NatureServe 2008).
Distribution, Status and Trends - Arctic-Alpine Disjunct Communities
Lake System
Superior
Michigan
Huron
St. Clair
Erie
Ontario
Coastal Reaches1
S2,S3a,S3b,S4a,S4c
Does not occur.
Does not occur.
Does not occur.
Does not occur.
Does not occur.
Key Coastal Reaches'
S3a,S4c
-
-
-
.
-
Status/ Trend
Good/ Improving
-
-
-
-
1 = Based on element occurrence (EO) data.
2 = Key Coastal Reaches include 10+ documented EOs, or the highest number of EOs for the lake.
This community is well-documented from Ontario, with over 50 occurrences, but is not tracked in the U.S. NatureServe (2008)
includes this community under Basalt (Conglomerate) Bedrock Lakeshore (Appendix A). This community occurs in many protected
areas, and protection was increased through recent initiatives in Ontario including the creation of Lake Superior National Marine
Conservation Area and several provincial Conservation Reserves. The new Marine Conservation Reserve protected some of the
best examples of this community, including several plants species that were not protected elsewhere (Bakowsky 1998b). The Lake
Superior North Shore Conservation Reserve (1,147 ha (2,834 acres)) also provides excellent representation of Arctic - Alpine
Disjunct Communities (Foster and Harris 2002).
3.10 Atlantic Coastal Plain Disjunct Communities
Global Status: Critically Imperiled
Related Coastal Terrestrial Ecosystems: Great Lakes Sand Beaches (small protected occurrences)
SOLEC 1996: Atlantic Coastal Plain Communities
Background: Atlantic Coastal Plain Disjunct Communities are a suite of plants that have their primary distribution on the Atlantic
seaboard, with scattered, disjunct populations in the Great Lakes. These populations were once connected, but became isolated as
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 22 —
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post glacial connections between the Great Lakes and Atlantic Ocean and Hudson River ended (Keddy 1991). In the Great Lakes,
Atlantic Coastal Plain Disjunct Communities primarily occur on sandy or peaty shores with fluctuating water levels.
Distribution, Status and Trends - Atlantic Coastal Disjunct Communities
Lake System
Superior
Michigan
Huron
St. Clair
Erie
Ontario
Coastal Reaches1
Does not occur.
M6a,M6b,M6c
HG9.HG10
Does not occur.
Does not occur.
Does not occur.
Key Coastal Reaches1
-
all coastal reaches have one occurrence
HG9
-
-
-
Status/ Trend
-
Mixed/ Undetermined
Mixed/ Undetermined
-
-
-
1 = Based on element occurrence (EO) data.
2 = Key Coastal Reaches with the highest number of EOs for the lake.
Two Atlantic Coastal Disjunct Communities have been documented (NatureServe 2008) (Appendix A). Inland Coastal Plain
Marsh is characterized by northern beaksedge, Virginia meadowbeauty (Rhexict virginico), longbeak beaksedge (Rhynchospora
scirpoides) and Hall's bulrush (Schoenoplectus hallii). The other type, Bulblet Flatsedge Coastal Plain Sandy Pondshore, is
reported from Ontario (NatureServe 2008), but it does not occur in Great Lakes coastal areas.
Atlantic Coastal Disjunct Communities are globally rare. These communities tend to be concentrated along the southern end of
Lake Michigan, and inland lakes between the ancient Lake Algonquin shore and present-day Georgian Bay coast (Keddy and
Sharp 1989). The Georgian Bay shoreline itself does host some of these communities, but is very high energy which makes it
difficult for the seedbank to persist. The overall scarcity of moist sandy shorelines limits the distribution of these communities.
3.11 Rich Coastal Fens
Global Status: Imperiled - Critically Imperiled
Related Coastal Terrestrial Ecosystems: Coastal Alvars
SOLEC1996: Not included (included as a coastal terrestrial feature by SOLEC in 1998; Reid et al. 1999)
Background: Coastal fens occur along level shorelines of northern Lake Michigan and Lake Huron (including southwestern
Georgian Bay). There also appear to be a few scattered occurrences in southern Lake Superior in Wisconsin and on Isle Royal.
These sites occupy embayments of open, sandy shorelines where limestone bedrock or cobble is at or near the surface. Shallow
bedrock differentiates coastal fens from interdunal wetlands or panes, which occur on a sand substrate. Coastal fens are
minerotrophic wetlands that receive groundwater inputs rich in calcium and magnesium carbonates and contain a rich assemblage
of calciphilic plants. The hydrologic regime of coastal fens is directly linked to that of the Great Lakes. The water table varies with
seasonal fluctuations in Great Lakes water levels including short-term changes due to seiches and storm surges, and long-term lake
level fluctuations. Rich coast fens can expand and contract depending on lake levels and location (Mortsch et al. 2008).
Distribution, Status and Trends - Coastal Fens
Lake System
Superior
Michigan
Huron
St. Clair
Erie
Ontario
Coastal Reaches1
S6c*
M2b,M4b*
HG1d,HG2b
Does not occur.
Does not occur.
Does not occur.
Key Coastal Reaches2
M2b
HG1d,HG2b
-
-
-
Status/ Trend
Undetermined/ Undetermined
Mixed/ Undetermined
Mixed/ Deteriorating
-
-
-
1 = Based on element occurrence (EO) data.
2 = Key Coastal Reaches with the highest number of EOs for the lake.
* = may not be "rich" fen.
Coastal fens frequently occur as part of a larger coastal complex that may include Great Lakes marshes, bedrock shores, rich
conifer swamp, and northern fen. The surrounding uplands of coastal fens are typically dominated by northern white cedar (Thuja
occidentalis). Rich Coastal Fens include two documented vegetation communities (NatureServe 2008) (Appendix A). Shrubby-
cinquefoil - Sweetgale Rich Shore Fen is dominated by low shrubs in association with graminoids. This community often occurs
in complexes with the second vegetation community: Great Lakes Sedge Rich Shore Fen. The Sedge Rich Shore Fen occurs in
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 23 —
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wetter fens and is dominated by including Canada bluejoint (Calamagrostis canadensis), Kalm's lobelia (Lobelia kalmii), green
sedge and twig-rush (Cladium mariscoides).
Both communities are considered globally rare (NatureServe 2008). Eleven high quality sites identified in Michigan and Wisconsin
totalled 1,100 ha (2,718 acres) (Mine and Albert 1998). While poorly documented in Ontario, coastal fens have been recorded
throughout the lower Great Lakes (Bakowsky 1995). The Ontario community of Coastal Meadow Marsh includes both shoreline
fens and interdunal pannes, and some occurrences may include perched-prairie fens (Bakowsky 1995).
Although numerous examples of coastal meadow marshes occur in protected sites such as provincial parks, national wildlife
refuges, and private nature reserves, not all of the types and rare species associations are represented in these areas (Bakowsky
1995).
3.12 Shoreline Alvars
Global Status: Imperiled - Critically Imperiled \
Related Coastal Terrestrial Ecosystems: Rich Coastal Fens, Bedrock Shores (Hmestone-dolostone types), Coastal Forests
SOLEC1996: Shoreline Alvars
Background: Alvars are naturally open habitats characterized by either a thin (less than 25 cm (9.8 in)), discontinuous or
nonexistent covering of loamy sand or sandy loam soil over calcareous bedrock such as limestone or dolostone. Alvars can range
from bare pavement to grassland to open woodland (NatureServe 2008). Vegetation consists mainly of sedges, grasses, mosses,
lichens or small herbaceous plants (EC and USEPA 2005). Alvars are often subjected to flooding and/or ice scouring in winter and
spring, and severe drought in summer (NHIC 2008).
Distribution, Status and Trends - Coastal Alvars
Lake System
Superior
Michigan
Huron
St. Clair
Erie
Ontario
Coastal Reaches'
Does not occur.
M1,M2a,M3
HG2a,HG2b,HG4a,HG7a,HG7b,HG8a
Does not occur.
E6b
OS1,OS3a,OS3b
Key Coastal Reaches'
-
HG2a,HG2b,HG4a,HG7b,HG8a
-
E6b
Status/ Trend
-
Good/ Unchanging
Good/ Improving
-
Mixed/ Improving
Mixed/ Unchanging
1 = Based on element occurrence (EO) data and Reschke et al. 1999.
2 = Key Coastal Reaches include endemic coastal community types.
Twelve of the 13 alvar vegetation communities identified in the Great Lakes basin occur on or near the coast. However, of these 12
systems only three are generally restricted to coastal terrestrial ecosystems: 1) Scrub Conifer/ Dwarf Lake Iris Alvar Shrubland; 2)
Creeping Juniper - Shrubby - Cinquefoil Alvar Pavement; and 3) Chinquapin Oak - Nodding Onion alvar woodland (Natureserve
2008) (Appendix A).
Over 80 alvar occurrences have been documented from the Great Lakes coast. This ecosystem has a very limited range and u>
restricted to the shores of eastern Lake Ontario, the western Lake Erie Islands, the Door Peninsula, the limestone/dolostone arch
from the southern Bruce Peninsula and Manitoulin Island to Drummond Island and very locally along Lake Michigan and Huron
and the northeastern shore of Michigan's lower peninsula. All of the coastal endemic systems are considered globally imperiled.
Scrub Conifer/Dwarf Lake Iris Alvar Shrubland is restricted to northern Michigan, and in Ontario on the southern shores of
Manitoulin Island and the Bruce Peninsula. Ten occurrences of this community were documented, with a total area of 330 ha
(815 acres). Creeping Juniper - Shrubby - Cinquefoil Alvar Pavement only occurs on the Bruce Peninsula, Manitoulin Island, the
islands north of Manitoulin and at three sites in northern Michigan. Twenty-four occurrences of this community were documented
with a total area of about 1,093 ha (2,700 acres). Chinquapin Oak - Nodding Onion alvar woodland is found only in western Lake
Erie on Pelee Island in southern Ontario, Canada (Reschke et al. 1999). This one occurrence has a total area of 12 ha (30 acres).
There has been significant progress in alvar conservation since the release of the technical report by the International Ahar
Initiative (Reid and Potter 2007, Reschke et al. 1999). This includes protection of several large coastal alvars along the southern
NEARSHORE AREAS OF THE GREAT LAKES 2009
24
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shore of Manitoulin Island and the Bruce Peninsula. Almost all of the alvars on Pelee Island are also now protected. Few coastal
alvars have been protected in eastern Lake Ontario.
3.13 Coastal Rock Barrens
Global Status: Vulnerable - Apparently Secure
Related Coastal Terrestrial Ecosystems: Bedrock Shores, Shoreline Cliffs, Alvars, Coastal Forests
SOLEC1996: Coastal Gneissic Rocklands (modified to include other coastal rocklands)
Background: This ecosystem includes coastal rock barrens that are within 2 km (1.2 mi) of the Great Lakes. While rock barrens
both on and off the Canadian Shield have been included in this analysis, communities based on sedimentary rock (e.g. limestone
and dolostone) are generally captured as alvar or open coastal forests. Rock barrens are not restricted to the coast in the Great
Lakes region (NCC 2006), but coastal occurrences tend to be variants of inland types due to greater wind and storm exposure,
which often limits or stunts tree growth (Jalava et al, 2005, Catling and Brownell 1999).
Distribution, Status and Trends - Coastal Rock Barrens
Lake System
Area (ha)/ % Coast
Superior
9,474/ 1.6%
Michigan
8,9747 2.4%
Huron
73,299/9.8%
St. Ctair
Erie
942/ 0.3%
Ontario
1,198/0.3%
Coastal Reaches'
Sedimentary: S1,S2,S3b,S5a,S6a,S6c,S7a,S7d,S7e
Canadian Shield:S1 ,S2,S3a,S3b,S4a,S4b,S4c,S5a,S5b,S6a,S6c, S7a,S7b,S7c
Sedimentary:M1,M2a,M2b,M3,M7a,LM
Sedimentary:HG1a,HG1b,HG1d,HG2a,HG2b,HG3,HG4a,HG4b,HG7a,HG7b,HG7c,HG10
Canadian Shield: HG8a,HG9
Does not occur.
Sedimentary: E1.E2.E6.E7
Sedimentary: OS1 ,OS3a,OS3b,OS4b,OS4c,OS5,OS6,OS7
Canadian Shield: OS2,OS3a
Key Coastal
Reaches2
S1,S3a,S3b
M1,M2a,
M2b,M7a,LM
HG8a,HG9
-
E6
OS1,OS3a,
OS7
Status/ Trend
Good/Improving
Undetermined*
Good/Improving
-
Undetermined*
Undetermined*
1 = Based on land cover mapping and element occurrence (EO) data. Boldface denotes coastal reach with documented EOs.
2 = Key Coastal Reaches include >10% of all ecosystem.
* = Status assessment was not completed for this ecosystem south of the Canadian Shield.
Two major coastal rock barren types have been described on the Canadian Shield (NatureServe 2008) (Appendix A). 1) Gneissic
or granitic barrens typically have over 30% bare bedrock and are characterized by common juniper with scattered red oak and
white pine. Where soil does exist, it tends to be thin lacustrine sand. Depressions in the rock are often flooded after the spring
thaw and rainfall (Macdonald 1986, NHIC 2008). This community is currently classified as Common Juniper Rocky Krummholz
(NatureServe 2008), but inventory work from Ontario and Michigan have not been integrated, and further characterization of this
ecosystem is required. Recent work has identified additional community types (Jalava et al. 2005). 2) Basalt bedrock systems are
found along the Lake Superior shorelines of the United States and Canada where it occurs between bedrock shores and forest.
Soils are thin and exposed areas of bedrock are common. This community consists of scattered trees, shrub thickets, and a layer of
graminoids, mosses, and lichens. Common trees include balsam fir (Abies balsamea), paper birch (Betulapapyriferd), white spruce
(Picea glauca), red pine, white pine, red oak and eastern white cedar (Thuja occidentalis). The bedrock includes basalt, volcanic
conglomerates, and localized rhyolites (Kost et al. 2007). It is unknown if any of the documented types are restricted to the coast.
Types that are characterized based on wind-stunted tree growth (i.e. Krummholz) are probably a coastal type.
Coastal rock barrens on granite and basalt have been poorly described and documented. While these systems can be locally
abundant, they do have a restricted range in the basin. The largest examples occur along the coast of northern and eastern Georgian
Bay, the Thousand Islands area of Lake Ontario at the St. Lawrence River (Reid and Holland 1997, NHIC 2008), and parts of Lake
Superior (NatureServe 2008). While development continues to occur in some areas, large areas have also been protected in recent
years.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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3.14 Great Lakes Coastal Forests
Global Status: Unknown
Related Coastal Terrestrial Ecosystems: Coastal Back Dune Complexes, Bedrock Shores, Cobble Forests, Shoreline Cliffs,
Shoreline Bluffs, Lakeplain Prairies, Shoreline Alvars, Coastal Rock Barrens
SOLEC1996: not included
Background: Approximately 61% of the Great Lakes basin is characterized by forest cover (Zuccarino-Crowe and Han 200'').
These forests play a critical role in water quality and quantity within the watershed, and forest cover along tributaries is recognized
as a key indicator of stream health (Environment Canada 2004). While we are beginning to get a better understanding of the link
between the health of coastal lands and nearshore aquatic systems (Introduction), the ecology of Great Lakes coastal forests is
poorly understood. Several studies have recognized the unique variations of forests along the Great Lakes coast. These variations
are expressed in differences in structure and composition (particularly in the north), and specialized functions due to their clo; e
proximity to the lakes. The localized climactic variations in the coast, such as strong and persistent winds and more frequent
lightening strikes and fire, alter forest structure (Kc&tef al. 2007). Dense fog and high humidity can also influence forests. Coast;!
forest characteristics documented from Lake Superior include a high richness and abundance of bryophytes, formation of peatlani is
(OMNR 1988a), stunted, "krummholz" trees (OMNR 1988b) and the development of unique forest stands on raised shoreli ic
features (e.g. cobble ridges). Coastal forests also provide important functions for migratory songbirds due to the seasonal abundance
of emerging aquatic insects. A recent study in western Lake Erie identified that forest patches near the coast are key migratory
stopover sites (Ewert et al. 2005). While no endemic coastal forest types have been described, there is good evidence that coastal
occurrences can be variants of communities that may be more widespread and common throughout the basin.
Distribution, Status and Trends - Great Lakes Coastal Forests.
Lake System
Area (ha)/ '% Coast
Superior
467,5367 80.1%
Michigan
110,173/28.9%
Huron
473,5547 59.9%
St. Clair
6,7277 9.5%
Erie
35,3057 14.2%
Ontario
85,7237 24.0%
Coastal Reaches1
All
All
All
All
All
All
Key Coastal Reaches2
S1,S2,S3a,S3b,S4a,S4c,S5b, S6b,S6c,S7a,S7c,S7d,S7e,LS
M1.M3.LM
HG2a,HG2b,HG3,HG4a,HG4b,HG5,HG7a,HG8a,HG9,HG10
SC2
E7d
OS7
Status/ Trend
Good/ Improving
Mixed/ Deteriorating
Mixed/ Unchanging
Poor/ Deteriorating
Poor/ Deteriorating
Mixed/ Unchanging
1 = Based on land cover mapping.
2 = Key Coastal Reaches include >70% natural cover (include non-forested systems), or the coastal reach with the highest amount of land cover.
One type of coastal forest has been described: White Spruce - Balsam Fir Conglomerate Woodland (Faber-Langendoen 2001
which occurs between bedrock coasts and inland forests of Lake Superior (Appendix A). These forests are characterized by thii
soils, exposed bedrock and open canopy.
There are approximately 1.2 million ha (2,965,265 acres) of coastal forests (defined as 2 km (1.2 mi) inland), comprising approximately
48% of the Great Lakes coastal terrestrial zone. Some of these forests overlap other coastal terrestrial ecosystems such as Coasta
Back Dune Systems. There are significant differences in the distribution of this system, which is entirely attributable to change;
in land use. While the coast of Lake Superior is still dominated by forests, Lake Michigan and Huron have higher forest cover it
the north, while Lake Ontario and Erie have greater cover in the eastern portion of their shores.
NEARSHORE AREAS OF THE GREAT LAKES 2009
26
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Pressure '
Maior/ Widespread
Minor/ Local
Indirect
Unknown
H
7
Great Sand
Lakes Beach
Great Lakes
Foredunes
tn
0)
X
., w
Coasta! Bac
Dune Comp
Bedrock Shores
Cobble Beaches
£
Shoreline Cl
u>
Shoreline Bl
(0
Jj
Lakeplain Pra
« £
c .2
5. ~
< " g
Hi
if .2 o
< Q O
tlantic Coasta
lain Disjuct
ommunities
Rich Coastal Fens
Shoreline Alvars
.*•
O
1
Coastal
Barrens
:orests
Coastal
1. Residential & Commercial Development
1.1 Housing & Urban Areas
1.2 Commercial & Industrial Areas
1.3 Tourism & Recreational Areas
2. Agriculture & Aquaculture
2.1 Annual & Perennial Non-Timber Crops
2.3 Livestock Farming & Ranching
-J
3. Energy Production & Mining
3.2 Mining & Quarrying
33 Renewable Energy
4. Transportation & Service Corridors
4.1 Roads & Railroads
5. Biological Resource Use
5.2 Gathering Terrestrial Plants
5.3 Logging & Wood Harvesting
_
6. Human Intrusions & Disturbances
6.1 Recreational Activities
7. Natural System Modifications
7.1 Fire & Fire Suppression
7.2 Dams & Water management/ Use
7.3 Other Ecosystem Modification
7
?
7
-r™
9
8. Invasive & Other Problematic Species & Genes
8.1 Invasive Non-Native/ Non-native Species
8.2 Problematic Native Species
9. Pollution
9.1 Household Sewage & Urban Waste Water
9.3 Agricultural & Forestry Effluents
9.4 Garbage & Solid Waste
11. Climate Change & Severe Weather
11.1 Habitat Shifting & Alteration
11.4 Storms & Flooding
7
7
7
7
X
?
Table 3. Summary of Pressures to Coastal Terrestrial Ecosystems.
' = Pressure categories based on Unified Classification of Direct Threats (IUCN-CMP 2006).
Pressures
Coastal terrestrial ecosystems are some of the most threatened in the Great Lakes region because they occupy the same land-water
interface where humans establish communities, industry and recreational land uses. This has resulted in the loss and degradation
of many habitats that are of North American and global conservation concern, including endemic Great Lakes coastal habitats. In
addition to their high intrinsic values, the status of coastal terrestrial ecosystems influences the quality and diversity of nearshore
waters, and has influences on some aerial migratory species such as songbirds that use coastal areas as stop-over habitat.
An automated analysis of pressures on coastal terrestrial ecosystems was conducted through G1S based on general landcover
and shoreline modification within each coastal eco-reach. Pressures were measured based on the percentage of urban cover and
agricultural cover within 2 km (1.2 mi) of the coast, and the percentage of shoreline that was classified as "artificial". Urban
land cover and artificial shorelines were scored higher than agricultural land uses as pressures to coastal terrestrial ecosystems.
Coastal ecoreaches that occur in Canada and the United States were assessed separately. There is a large positive correlation
between shoreline modification and urban land use (coefficient of correlation = 0.58) and a large negative correlation between
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 27
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shoreline modification and natural cover (coefficient of correlation = -0.67). Agricultural land use has a low correlation to artific al
shorelines.
Based on this analysis the coastal ecoreaches under the greatest pressures (top 80th percentile) include the Duluth area in Lake
Superior (S6a), southwestern portion of Lake Michigan (M5, M4b, M4a), the western and northern coast of Lake Ontario (OS^-a,
OS4b), the southern shore of Lake Erie (E7a, E7b, E7c), the Niagara River in the United States (El), the Detroit and St. Clair Rivers
(SCI, SC3), western Lake Erie in the U.S. (E6a, E6b) and Lake St. Clair in the U.S. (S2). These high pressure rankings are based
on a high percentage of urban land cover (average 47.8%) and artificial shore (average 31.5%).
Coastal ecoregions with the lowest pressures include most of Lake Superior (S2, S3a, S3b, S4a, S4b, S4c, S6c, S7a, S7c, S7d,
S7e), St. Marys River in the U.S. (SI), eastern Georgian Bay and the North Channel (HG8a, HG9), western Bruce Peninsula and;
Manitoulin Island (HG2a, HG2b, HG7a), northwestern Lake Huron (HG4a, HG3) and northern Lake Michigan islands and coest
(Ml, LM). These low pressure rankings are based on a low percentage of urban land cover (average 2.3%) and artificial shore
(average 1.7%). These coastal terrestrial ecosystems^lso have lower agricultural cover.
The project also assembled information on protected areas along the Great Lakes coast to provide an assessment of land protection
by regulated public lands (e.g. National Parks, Conservation Reserves, State Park, National Forest etc). While these designations
do not protect coastal terrestrial ecosystems from all pressures, and variable resources uses are permitted, these areas are generally
protected from future development. Land protection is much higher along coasts in the upper Great Lakes and many coastal
ecoreaches have > 50% of the total area in public lands/ protected areas (e.g. S3a, S3b, S4b, S5b, HG9). In the lower lakes, only
smaller coastal ecoreaches based on Lake Erie sandspits have higher levels of land protection (i.e. Long Point and Presque Isle).
Most coastal ecoreaches in the lower Great Lakes have < 5% of the total area in public lands/ protected areas (e.g. E2, OS1, HGlc).
The St. Mary's River also has little public lands/ protected areas.
The review of pressures on the coastal terrestrial ecosystems is based on a review of the literature and discussions with experts
(Table 3). Identified pressures for each coastal terrestrial ecosystem were categorized into standard classes (IUCN-CMP 2006)
based on their scope and potential severity.
The following provides a summary of information from the literature on pressures to coastal terrestrial ecosystems:
Great Lakes Sand Beaches: While the beach ecosystem is very dynamic and resilient to change, it is very susceptible to changes
in coastal processes that reduce sand transport and deposition. Threats to sand beaches include: off-leash dogs and hyper-abundant
populations of raccoon (Procyon lotor) that disturb fauna such as piping plover (Charadrius melodus) (Kost et al. 2007); heavy
recreational use that disturbs fauna and tramples vegetation (Kost et al. 2007, WDNR 2006); off-road vehicles that disturb
vegetation (Kost et al. 2007, WDNR 2006); beach grooming which removes vegetation and habitat (Kost et al. 2007, WDNR
2006); sand mining (WDNR 2006); creation of artificial shorelines and shoreline hardening which leads to a loss in the longshore
sediment transport processes which naturally erode and replenish beaches and support their unique dynamic processes; invasivf
plants, zebra (Dreissena polymorpha) and quagga mussels (Dreissena bugensis) which change beach substrates; and housini
development (WDNR 2006).
Beaches tend to become thinner and more narrow "down current" from jetties, breakwaters and other hardened shoreline;
Protective beaches can be eroded, increasing wave energy onto backbeach dune and wetland systems. This problem is particular!
pertinent on the sand beaches of Lake Ontario, Lake Erie and somewhat in western Lake Superior.
Great Lakes Foredunes and Coastal Backdune Complexes: Dunes face an extensive threat from human disturbance, and are bein j
lost to development, sand mining, recreational trampling, invasive species (e.g. baby's breath (Gypsophila paniculatd), spottei
knapweed (Centaureastoebe)), shoreline condominium and second home development, off-road vehicles and recreational use (Sill
2007). All of these practices are known to impact, level, degrade or destroy the dunes, and a loss of structure and dune vegetatioi a
leads almost immediately to dune erosion (Silk 2007). Blowouts can occur very quickly on a dune on which vegetation has beet t
disturbed, and this gap is often immediately excavated by wind, leading to further loss of sand and vegetation and resulting ina
a large depression in the dune structure (Hill 1993). Erosion is a very serious threat for this community type as dunes can bsaf
challenge to restore, and the loss of unique species can be irreversible. Boardwalks and dune walkovers have been constructed over
NEARSHORE AREAS OF THE GREAT LAKES 2009
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some sand dunes and active restoration via the planting native beach grass and removal of invasive species has been shown to help
preserve and restore dune ecology (Silk 2007). Shoreline alterations impacting coastal processes and beach raking have also been
identified as pressures (Peach 2006). Other threats include deer browse, cottage development, high controlled water levels and
invasive alien species (Bakowsky 1998a). Ridges and wetland swales have been degraded by off-road vehicles, heavy foot-traffic
and invasive species (Kost et al. 2007). The invasive common reed (Phragmites australis) may establish in low interdunal areas
and expand onto upland dunes. Many backdune areas are under threat of development for cottages and second homes.
Bedrock Shores: The threats to bedrock shores include trampling of limited vegetation by humans, invasive species and the use
of off-road vehicles (Kost et al. 2007, WDNR 2006). Development of adjacent shorelines contributes to these pressures. Some
localized aggregate operations along the coast also impact this system. Invasive species are more likely to occur at sites that lack
a forest buffer (Kost et al. 2007)
Cobble Beaches: Cobble beaches ecosystems are resilient ecosystems because they are adapted to very dynamic conditions.
Shoreline development can result in increased disturbances to cobble beaches including the removal of cobble and dock construction.
Development can also increase associated human activity, such as shoreline recreation, pets (which can disturb fauna), off-road
vehicle usage, and the introduction of invasive species (Adams 2007, Kost et al. 2007). Some cobble beaches could be impacted by
regulation of Great Lakes water levels.
Shoreline Cliffs: Shoreline cliffs are highly enduring features with little commercial value (e.g. timber). Threats tend to be
associated with land uses on adjacent lands and recreational uses. These include development, logging of adjacent forests causing
cliff top erosion, foot traffic on cliff edges, rock climbing, quarrying and invasive plants (Kost et al. 2007, WDNR 2006). Some
sections of shoreline cliffs are at risk for development, but for the most part the difficulty and instability of the terrain allows for
some level of protection from human intervention. There may be a potential threat to the flora of diabase cliffs in Lake Superior
through the inadvertent application of aerial herbicide, which is sometimes used as part of a silvicultural treatment in regenerating
or re-planted forests (Bakowsky 2002).
Shoreline Bluffs: Threats which can affect sensitive bluff ecosystems include shoreline development, bluff-top development,
mining and quarrying, and problems with invasive species. However, the main threats are associated with erosion. Clearing of
adjacent lands for agriculture, deforestation, recreational facilities, trails and roads can cause disturbance of bluffs and tablelands
which can exacerbate erosion (WDNR 2006). Further disturbance encourages erosion, often to the point where deep gullies are
formed and changed to ravine systems, by which water will further erode the bluff. Shoreline stabilization and armouring is
common at the base of many bluffs.
Lakeplain Prairies: The main threat to lakeplain prairies is continued conversion, alterations to groundwater and fire suppression
(Albert and Kost 1998, Albert 1998). Ditching near existing sites, including protected areas, is one of the key threats, as this can
increase the cover of woody species by lowering the water table. Beavers can also impact the landscape with flooding, which can
suppress fires necessary to maintain open habitat, and increase the size of adjacent swamp and marsh communities at the cost of
the loss of lakeplain prairie habitat. Grazing has also been identified as a localized pressure (WDNR 2006).
Arctic - Alpine Disjunct Communities: There is some evidence of trampling and uprooting of sensitive plant species in more
highly used recreational areas. Second home development has recently become a significant threat to the Lake Superior coast.
Second home development on the U.S. shore of Lake Superior has spiked markedly in price, thus shifting development pressure
to the Canadian shore of Lake Superior. Large portions of the coast are unprotected, so this threat is likely to continue to increase
in magnitude unless some level of protection is offered to the Lake Superior shores which support significant plant communities.
Climate change could have a negative impact on this community.
Atlantic Coastal Plain Disjunct Communities: Threats to Atlantic coastal plain disjunct communities include shoreline recreational
and residential development, which directly destroys habitat, especially for those species that tend to occupy the drier portion of
the community gradient. Disturbance of these areas from recreational activities such as off-road vehicles, hiking, and boating can
also be problematic for the generally sensitive plant species. Stabilized water levels are perhaps the most severe problem, as these
plants rely on fluctuating water levels to maintain their populations, and periodic flooding kills woody species, which shade out
NEARSHORE AREAS OF THE GREAT LAKES 2009
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coastal plain disjuncts (Kost et al. 2007, Reid and Holland 1997). Invasive species tolerant of periodic flooding have the potential
to outcompete native species.
Rich Coastal Fens: Pressures to rich coastal fens include alterations to hydrology, development, road construction and upgrades,
off-road vehicles and invasive species (Kost et al. 2007, Bakowsky 1995). The hydrology of these systems is very specific and
contraction adjacent to the fen can result in hydrological changes that drastically alter the vegetation. Off-road vehicles can create
ruts that alter surfoce flows. These systems are also vulnerable to invasive species, especially if the hydrology has been altered.
Invasive species of greatest concern include glossy buckthorn (Frangula alnus), common reed, reed canary grass (Phalaris
anmdinacea), purple loosestrife (Lythrum salicarid) and narrow-leaved (Typha angustifolia)/ hybrid cattail (Typha x glauca) (Kost
et al. 2007). Nutrient cycles and plant communities could also be disrupted by atmospheric deposition of nitrogen which could alter
native plant dominance and promote invasive species.
Shoreline Alvars: Range-wide pressures to coastal alvar ecosystems are: development, off-road vehicles, grazing and browsing,
exotic species, plant collecting and forestry (Reschke et al. 1999). Fire probably once played a very important role in limiting tree
establishment in grassland alvars (Kost et al. 2007), but years of fire suppression have likely converted many grassland alvars to
wooded ones. Many coastal alvars have been protected since the International Alvar Initiative (Reschke et al. 1999).
Coastal Rock Barrens: Threats to this coastal terrestrial ecosystem are mainly from shoreline development and recreational
uses such as campsites and boat launches (Reid and Holland 1997, NHIC 2008). Other pressures include flooding due to dam
construction, mineral extraction, fire suppression and recreational development (Catling and Brownell 1999), off-road vehicles and
invasive species (Kost et al. 2007). The importation of fill for cottage septic systems may be a significant vector for invasive plants.
Coastal Forests: Pressures to coastal forests highly vary because of its wide distribution and diversity. In the south, development,
deer browse and invasive species are key pressures. Some invasive insects, such as emerald ash borer (Agrilus planipennis), could
alter the composition of large areas of forest. In northern Great Lakes coastal forests, incompatible forestry and mining are the
major pressures. Climate change could alter micro-climactic conditions.
Management Implications
Understanding of the coastal terrestrial ecosystems of the Great Lakes has greatly increased in the last decade, and there have
been significant increases in the amount of protected areas, improvements in management, greater recognition in policy and better
community support and engagement in conservation. While this has reduced pressures for some coastal terrestrial ecosystems in
some areas, these efforts need to be expanded. Since 1996, several important examples of Great Lakes coastal ecosystems have
been significantly altered or destroyed by residential and second home development including dunes, bedrock beaches and coastal
forests. There are also increasing threats related to wind development projects. Invasive species, including within most protected
areas, continue to be a high threat.
Most of the growth in protected areas since 1996 has occurred in Ontario through the Ontario Living Legacy program (OMNR
1999) which resulted in the designation of several large coastal areas as Provincial Parks, Provincial Park additions, Conservation
Reserves and Enhanced Management Areas. Some of the larger areas include Lake Superior Archipelago Conservation Reserve
(51,577 ha (127, 450 acres)), Killarney Coast and Islands Provincial Park (13,791 ha (34,078 acres)), North Channel Inshore
Waterway Provincial Park (7,132 ha (17,624 acres)), Lake Superior Shoreline Enhanced Management Area (19,605 ha (48,445
acres)) and the designation of the Lake Superior National Marine Conservation Area. Other protection efforts have been underway
in the United States, including protection of much of the shoreline of the Keweenaw Peninsula, Michigan and application of
conservation easements to many shoreline areas along the Detroit River. While land protection reduces some potential pressures
to such as incompatible development, effective management of protected areas is required to protect the health of coastal terrestrial
ecosystems.
Some of the management implications for consideration of future action are:
• There needs to be a binational effort to classify and map coastal terrestrial ecosystems of the Great Lakes. This project
assembled the best available information, but these datasets are inconsistent in their approach and classification between
Canada and the United States. Several ecosystem types are still relatively poorly understood and may require the
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 30 —
-------
description of additional types (e.g. bedrock shores). Other modifications to Great Lakes coastal classifications need to
occur to better reflect ecosystem structure and composition. For example, cobble beaches are grouped by geology, but it
has been recognized that structure is probably a more important determinant of vegetation communities (Kost et al. 2007)
and better reflects coastal processes.
• Several coastal areas of the Great Lakes have not been fully inventoried. Information in this report can be used to identify
potential sites in need of further inventory. For example, several coastal ecoreaches in Lake Superior (e.g. SI, S3b, S4a,
S4c) have large areas of cobble beach, but no element occurrences (EOs) have been documented. While most coastal
ecoreaches on Lake Michigan have EO data for sand beaches, only five of the 17 coastal eco-reaches on Lake Huron that
have sand beaches have EO information (e.g. coastal ecoreach HG5 is a large sand beach area with no EO data). There
needs to be a focussed effort to inventory coastal ecosystems, particularly those of global conservation concern. This
information is needed to better inform management and policy decisions.
• Land protection and management of key sites needs to be a priority in the next ten years. Residential and recreational
developments are rapidly expanding in many areas. Opportunities to protect some of these places will be lost. Coastal
terrestrial ecosystems should be a focus of land conservation in the Great Lakes.
• Many important coastal terrestrial ecosystems are within protected areas and public lands. These sites need to have
effective management plans that identify and mitigate potential threats, in particular invasive species and incompatible
recreation.
• While coastal classification schemes and the approach of this report examine systems as separate units, in many places
these ecosystems occur as diverse ecosystem complexes. Conservation of these large, diverse landscapes should be a
priority. The integrity of many coastal systems is greatly enhanced by maintaining their landscape context, including
forested buffers.
Comments from the authors
This report has generated information that can be used to report on each coastal ecoreach (e.g. length of coastal terrestrial
ecosystems, pressures index, land cover, protected lands). This information could be used to provide contextual reports for each
coastal ecoreach.
Acknowledgments
Authors:
Dan Kraus, Nature Conservancy of Canada - Ontario Region (Guelph, ON), dan.kraus@natureconservancy.ca
Gary White, Nature Conservancy of Canada - Ontario Region (Guelph, ON), gary.white@natureconservancy.ca
Contributors:
Dave Ewert, The Nature Conservancy
Rachael Franks Taylor, The Nature Conservancy
Bonnie Henson, Ontario Natural Heritage Information Centre
Mary Harkness, The Nature Conservancy
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Appendix A: Classification of Great Lakes Coastal Terrestrial Ecosystems
Ecosystems Addressed
in this Report
SOLEC 1996 Name
Ecological System1
Vegetation Community [Common
Name (Global Rank)2]
Great Lakes State/ Provincial Classification3
Notes
Great Lakes Sand Beaches
Sand Beaches
Great Lakes Dune
Great Lakes Beach (G3)
Northern Great Lakes Dune Grassland
(GNR)
Beach/ Shore Dunes, Great Lakes Type (IL)
Sand /Gravel Beach (Ml)
Sand Beach (MM)
Lake Beach - Sand Subtype (MN)
Sand Beach (NY)
Beach-Dune Community (OH)
Sea Rocket Open Mineral Shoreline Type (ON)
Reed-canary Grass Mineral Open Beach Type (ON)
Great Lakes Sand Spit (PA)
Great Lakes Sparsely Vegetated Beach (part of Great Lakes
Region Beach-Dune-Sand Plain Complex) (PA)
Great Lakes Beach (Wl)
Primary sand beach below
high water mark.
Great Lakes Foredunes
Sand Dunes
Great Lakes Dune
Great Lakes Beachgrass Dune (G3G5)
Cottonwood Dune (G1G2)
Sand Cherry Dune Shrubland (G2Q)
Great Lakes Juniper Dune Shrubland
(G3G4)
Northern Great Lakes Dune Grassland
(GNR)
Shrub Dune Sparse Vegetation (GNR)
Beach/Shore Dunes, Great Lakes Type (IL)
Primary Dune - Lake (IN)
Open Dunes (Ml)
Great Lakes Dune (Ml)
Beachgrass Dune (MN)
Juniper Dune Shrubland (MN)
Great Lakes Dune (NY)
Beach-Dune Community (OH)
Little Bluestem-Swttcn Grass-Beachgrass Open Dune Type
(ON)
Little Bluestem-Long-leaved Reed Grass-Great Lakes
Wheatgrass Open Dune Type (ON)
Sand Dropseed - Flat Stemmed Bluegrass Open Sand Dune
Type (ON)
Sand Cherry Shrub Sand Dune Type (ON)
Hop-tree Shrub Sand Dune Type (ON)
Willow Shrub Sand Dune Type (ON)
Dogwood Shrub Sand Dune Type (ON)
Juniper Shrub Sand Dune Type (ON)
Red Cedar Treed Dune Savanna Type (ON)
Cottonwood Treed Dune Savanna Type (ON)
Balsam Poplar Treed Dune Type (ON)
Hackberry - Basswood - Oak Treed Sand Dune Type (ON)
Sand Dune (PA)
Great Lakes Region Bayberry - Cottonwood Community
(part of Great Lakes Region Beach-Dune-Sand Plain
Complex) (PA)
Great Lakes Dune (Wl)
Herbaceous and shrub
dominated dunes above high
water mark.
Coastal Back Dune Com-
plexes
Sand Barrens
Great Lakes Dune and Swale
Northern Great Lakes Interdunal
Wetland
Great Lakes Wooded Dune and Swale
Complex (G3)
Great Lakes Dune Pine Forest (G3Q)
Great Lakes Pine Barrens (G2)
Interdunal Wetland (G3?)
Alkaline Shoredunes Pond/ Marsh, Great Lakes Type (IL)
Barrens, Central Midwest Type (IL)
Wetland Panne (IN)
Interdunal Wetland (Ml)
Wooded Dune and Swale Complex (Ml)
Great Lakes Barrens (Ml)
Beach Ridge Shrubland (Lake Superior) (MN)
Beach Ridge (PA)
Great Lakes Region Bayberry - Mixed Shrub Palustrine
Shrubland* (PA)
Great Lakes Region Palustrine Sandplain* (PA)
Great Lakes Region Dry Sandplain' (PA)
* part of Great Lakes Region Beach-Dune-Sand Plain
(PA)
Great Lakes Barrens (Wl)
Great Lakes Ridges and Swale (Wl)
Great Lakes Barrens (Wl)
Interdunal Wetland (Wl)
Defined by stabilized back
dunes and includes a complex
of upland and wetland com-
munities. Modified from 1996
report to include all communi-
ties that occur in complex.
Bedrock Shores
Bedrock and Cobble
Beaches
Great Lakes Alkaline Rocky Shore
and Cliff
Great Lakes Limestone - Dolostone
Bedrock Shore (G3)
Great Lakes Basalt - Conglomerate
Bedrock Shore (G4G5)
Great Lakes Acidic Rocky Shore and
Cliff
Great Lakes Granite - Metamorphic
Bedrock Shore (GNR)
Great Lakes Sandstone Bedrock Shore
(G3G4)
Cobble Shore (NY)
Basalt Bedrock Lakeshore (Ml)
Limestone Pavement Lakeshore (Ml)
Volcanic Conglomerate Bedrock Lakeshore (Ml)
Lake Superior Rocky Shore (MN)
Dry Bedrock Shore (Lake Superior) (MN)
Wet Rocky Shore (Lake Superior) (MN)
Lake Beach (Lake Superior) Bedrock Subtype (MN)
Shrubby Cinquefoil Carbonate Open Bedrock Beach Type
(ON)
Sandstone Bedrock Beach/ Bar Ecosite (ON)
Granite Bedrock Beach/ Bar Ecosite (ON)
Great Lakes Alkaline Rockshore (Wl)
Bedrock Shore (Wl)
Typically bedrock that occurs
above the high water mark
or storm surges. Modified
from 1996 report (cobble
and bedrock split) because
of significant differences in
vegetation communities. Two
major sub-types can generally
be defined by coastal unit
NEARSHORE AREAS OF THE GREAT LAKES 2009
35
-------
Ecosystems Addressed
in this Report
SOL£C 1996 Name
Ecological System1
Vegetation Community [Common
Name (Global Rank)2]
Great Lakes State/ Provincial Classification3
Notes
Cobble Beaches
Bedrock and Cobble
Great Lakes Alkaline Rocky Shore
and Cliff
Great Lakes Limestone Cobble -Gravel
Shore (G2G3)
Great Lakes Basalt - Diabase Cobble -
Gravel Shore (G4G5)
Great Lakes Acidic Rocky Shore and
Cliff
Great Lakes Non-alkaline Cobble -
Gravel Shore (G2G3)
Great Lakes Sandstone Bedrock Shore
(G3G4)
Limestone Cobble Shore (Ml)
Sandstone Cobble Shore (Ml)
Cobble Beach (Ml)
Gravel/ Cobble Beach (Lake Superior) (MN)
Wet Rocky Shore (Lake Superior) Cobble Subtype (MN)
Lake Beach (Lake Superior) Gravel-Cobble Subtype (MN)
Cobble Shore Wet Meadow (NY)
Wormwood Gravel Open Beach Type (ON)
Red Cedar-Common Juniper Shingle Shrub Beach Type
(ON)
Willow Gravel Shrub Beach Type (ON)
Typically cobble/ gravel that
occurs above the high water
mark or storm surges. Modi-
fied from 1996 report (cobble
and bedrock split) because of
significant differences in veg-
etation communities. Cobble
beaches were treated sepa-
rately by SOLEC in 1998. Two
major sub-types can generally
be defined by coastal unit.
Shoreline Cliffs
Limestone Cliffs and Talus
Slopes
Great Lakes Alkaline Rocky Shore
and Cliff
Great Lakes Shore Limestone - Dolos-
tone Cliff (G4G5)
Great Lakes Shore Basalt - Diabase Cliff
(GNR)
Great Lakes Acidic Rocky Shore and
Cliff
Great Lakes Snore Granite - Metamor-
phic Cliff (GNR)
Great Lakes Shore Sandstone Cliff
(G4G5)
Sandstone Lakeshore Cliff (Ml)
Basalt Lakeshore Cliff (Ml)
Volcanic Conglomerate Lakeshore Cliff (Ml)
Dry Non-acid Cliff (Ml)
Moist Non-acid Cliff (Ml)
Moist Acid Cliff (Ml) \
Dry Cliff (MN) X
Moist Cliff (MN)
Exposed Mafic Cliff (Lake Superior) (MN)
Sheltered Mafic Cliff (Lake Superior) (MN)
Exposed Felsic Cliff (Lake Superior) (MN)
Calcareous Cliff Community (NY)
Moist Cliff (Wl)
Moist Cliff (Wl)
Ontario has over 20 diff/talus
communities. None of these
are classified as coastal
Modified from 1996 report to
include all coastal cliff types
that had been documented.
Two major sub-types can
generally be defined by
coastal unit.
Shoreline Bluffs
Unconsolidated Shoreline
Bluffs
None?
Clay Seeps (GNR)
Poorly Consolidated Slope, Midwest Type (IL)
Great Lakes Bluff (NY)
Open Clay Bluff (ON)
Open Sand/ Clay Bluff Type
Great Lakes Region Scarp Woodland (part of Great Lakes
Scarp Complex) (PA)
Clay Seepage Bluff (Wl)
Also reported from Michigan
and Ontario.
Lakeplain Prairies
Lakeplain Prairies
Great Lakes Wet-Mesic Lakeplain
Prairie
Lake Plain Mesic Oak Woodland (G2)
Lakeplain Wet-Mesic Prairie (G2)
Lakeplain Wet-Mesic Oak Opening (G1)
Lakeplain Wet Prairie (G2G3)
Wet Prairie (IL)
Prairie - Sand Wet (IN)
Prairie - Sand Wet-Mesic (IN)
Lakeplain Wet-Mesic Prairie (Ml)
Lakeplain Oak Openings (Ml)
Lakeplain Wet Prairie (Ml)
Fresh-Moist Tallgrass Prairie (ON)
Fresh-Moist Pin Oak-Bur Oak Tallgrass Savannah Type (ON)
Fresh-Moist Black Oak-White Oak Tallgrass Woodland Type
(ON)
Fresh-Moist Pin Oak Tallgrass Woodland Type (ON)
Bluejoint-Prairie Slough Grass Tallgrass Meadow Marsh
Type (ON)
Wet-Mesic Prairie* (Wl)
Wet Prairie (Wl)
"Wisconsin wet prairie types include lakeplain coastal types
and interior prairies.
Arctic-Alpine Disjunct
Conmiurdttes
Arctic-Alpine Disjunct Com-
munities
Great Lakes Alkaline Rocky Shore
and Cliff
Great Lakes Arctic-Alpine Basic Open Bedrock Shoreline
Type (ON)
Also nested with non-alkaline
bedrock shores (basalt), but
treated separately due to
special features.
Atlantic Coastal Plain Dis-
junct Communities
Atlantic Coastal Plain Dis-
Junct Communities
None?
rtand Coastal Plain Marsh (G2?)
Bulbet Ratsedge Coastal Plain Sandy
Pondshore (G2)
Coastal Plain Marsh (Ml)
Atlantic Coastal Plain Shallow Marsh Type (ON)
Wetland/ terrestrial interface.
Rich Coastal Fens
New
Great Lakes Alkaline Rocky Shore
and Cliff
Shrubby-cinquefoil - Sweetgate Rich
Shore Fen (G1G2)
Great Lakes Sedge Rich Shore Fen
(G1G2)
Graminoid Coastal Meadow Marsh Type (ON)
Shrubby Cinquefoil Coastal Meadow Marsh Type (ON)
Shore Fen (Wl)
Calcareous Fen (Wl)
Ontario types could also be
included as Cobble Beach
(alkaline).
Wetland/ terrestrial interface.
Shoreline Alvars
Shoreline Alvars
Great Lakes Alvar
Scrub Conifer/Dwarf Lake Iris Alvar
Shrubland (G1G2)
Creeping Juniper - Shrubby Cinquefoil
Alvar Pavement (G2)
Alvar (Ml)
Calcareous Pavement Barrens (NY)
Alvar (OH)
Scrub Conifer-Dwarf Lake Iris Shrub Alvar Type (ON)
Creeping Juniper - Shrubby Cinquefoil Dwarf Shrub Alvar
Type (ON)
Alvar (Wl)
This report only includes
alvar types that are generally
restricted to the coastal area
of the Great Lakes.
Modified from 1996 report to
only include alvar communi-
ties that are influenced by the
coastal environment.
NEARSHORE AREAS OF THE GREAT LAKES 2009
36
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Ecosystems Addressed
in this Report
SOLEC 1996 Name
Coastal Gneissic Rocklands
Great Lakes Coastal
Forests
New
Ecological System1
Vegetation Community [Common
Name (Global Rank)2!
Great Lakes Acidic Rocky Shore and
Cliff
Great Lakes Alkaline Rocky Shore
and Cliff
Common Juniper Rocky Krummholz
(G3G4)
Basalt Bedrock Glade (G?)
Mone?
Great Lakes Spruce - Fir Basalt Bedrock
Shore (GNR)
Great Lakes State/ Provincial Classification3
Northern Bald (Ml)
Volcanic Conglomerate Bedrock Glade (Ml)
Basalt Bedrock Glade (Ml)
Bedrock Shrubland (Lake Superior) (MN)
Lake Superior Rocky Shore/ Bedrock Shrubland/ Bedrock
Outcrop Complex (MN)
Blueberry Granite Shrubland Barren Type (ON)*
Oak - Red Maple - Pine Treed Granite Barren Type (ON)*
Pitch Pine Treed Granite Barren Type (ON)*
Chokeberry Granite Shrubland Barren Type (ON)
Common Juniper Granite Shrubland Barren Type (ON)
Jack Pine Treed Granite Barren Type (ON)
Red Cedar Treed Granite Barren Type (ON)
Dry Granite Barren Type (ON)
Dry Moss Non-Calcareous Open Rock Barren Type (ON)
Non-Calcareous Poverty Oat Grass Rock Barren Meadow
Type (ON)
Non-Calcareous Tuffted Hairgrass Rock Barren Meadow
Type (ON)
Raspberry Non-Calcareous Shrub Rock Barren Type (ON)
Cinquefoil Non-Calcareous. Shrub Rock Barren Type (ON)
White Pine - Oak - Red Cedar Non-Calcareous Treed Rock
Barren Type (ON)
"Ontario community types with documented coastal occur-
rences.
Notes
Modified to include all coastal
rock barrens (except alvars).
Rock barrens that are influ-
enced by the coastal environ-
ment. Occurs as a narrow
band between bedrock shores
(non-alkaline) and interior rock
barrens.
Forests that occur within 2 km
of the coast and are influenced
by the coastal environment.
2 = Global Rank Descriptions:
G1 Critically Imperiled-At very high risk of extinction due to extreme rarity (often 5 or fewer populations), very steep declines, or other factors
G2 rnperiled—At high risk of extinction due to very restricted range, very few populations (often 20 or fewer), steep declines or other factors '
G3 Vulnerable-At moderate risk of extinction due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines or
G4 Apparently Secure—Uncommon but not rare; some cause for long-term concern due to declines or other factors
Go Secure—Common; widespread and abundant.
3 = Sources for state/ provincial classification:
Illinois: White and Madany (1978)
Indiana: Indiana Department of Natural Resources (2008); Homoya et al (1988)
Michigan: Kost ef al. (2007)
Minnesota: Minnesota Department of Natural Resources (2008); Minnesota Natural Heritage Proqram (1993)
New York: Edinger et al. (eds) (2002)
Ohio: Anderson (1982)
Ontario: Ontario Natural Heritage Information Centre (2008)
Pennsylvania: Fike (1999)
Wisconsin: Wisconsin Department of Natural Resources (WDNR 2006)
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Appendix B: Data Sources
Shoreline Mapping
The distribution and extent of nearshore coastal ecosystems were measured using a combination of spatial shoreline data and
element occurrence information. These data were also used to determine the extent of artificial shoreline.
The following ecosystems were assessed using shoreline mapping information from Environment Canada and NOAA: Sand
Beach, Bedrock Shore, Cobble Beach, Shoreline Cliff and Shoreline Bluff. Table Al provides a summary of the shoreline mapping
information that was available for Canada and the U.S. and how it was cross-walked.
Table A1. Shoreline Mapping.
Environment Canada Shoreline Classification 1
ID Morphology Class |
lla
1h
1c
2
3
4
5a
5b
6
7a
7b
7c
8
9
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
11
12
13a
13b
Exposed Bedrock Bluff less than 1 metre elevation
Exposed Bedrock Bluff 1-5 metre elevation \
Exposed Bedrock Bluff greater than 5 metre elevation \
Retaining Wall/Harbour Structure/Breakwaters
Shelving Bedrock
Exposed Sediment Bluff
Sand Beach: DeposWonal
Sand Beach: Erosional or Transitory
Sand Barrier With Lagoon
Pebble Beach
Pebble/Cobble Beach
Cobble Beach
Rip Rap —
Boulder Beach
Mixed Beach (40% Boulder. 30% Cobble, 30% Sand)
Mixed Beach (40% Pebble. 40% Cobble, 20% Boulder)
Mixed Beach (40% Sand. 60% Pebble)
Mixed Beach (50% Boulder, 30% Cobble, 20% Sand)
Mixed Beach (50% Boulder, 50% Cobble)
Mixed Beach (50% Cobble. 50% Boulder)
Mixed Beach (50% Sand. 10% Pebble, 35% Cobble)
Mixed Beach (50% Sand, 25% Pebble, 25% Cobble)
Mixed Beach (50% Sand, 50% Cobble)
Mixed Beach (50% Sand, 50% Pebble)
Mixed Beach (60% Boulder. 20% Cobble, 20% Sand)
Mixed Beach (60% Boulder, 30% Cobble, 10% Sand)
Mixed Beach (60% Boulder, 40% Cobble)
Mixed Beach (60% Sand, 20% Pebble, 20% Cobble)
Mixed Beach (60% Sand, 40% Pebble)
Mixed Beach (70% Boulder, 30% Cobble)
Mixed Beach (70% Cobble, 30% Boulder)
Mixed Beach (70% Pebble, 20% Cobble, 10% Boulder)
Mixed Beach (70% Sand, 15% Pebble, 15%Cobble)
Mixed Beach (70% Sand. 30% Cobble)
Mixed Beach (70% Sand, 30% Pebble)
Mixed Beach (80% Boulder, 20% Cobble)
Mixed Beach (80% Cobble, 20% Boulder)
Mixed Beach (80% Cobble, 20% Sand)
Mixed Beach (80% Pebble. 20% Cobble)
Mixed Beach (80% Pebbles, 20% Boulders)
Mixed Beach (80% Sand. 10% Cobble, 10% Boulder)
Mixed Beach (80% Sand, 10% Pebble, 10% Cobble)
Mixed Beach (80% Sand. 20% Boulder)
Mixed Beach (80% Sand. 20% Cobble)
Mixed Beach (80% Sand, 20% Pebble)
Mixed Beach (90% Cobble, 10% Boulder)
Mixed Beach (90% Sand, 10% Pebble)
Low Vegetated Bank (Grass or Trees)
Delta Mud Flat
Fringing Wetland
Broad Wettand
Jedrock Shore
Shoreline Cliff
Shoreline Cliff
Artificial
Bedrock Shore
Shoreline Bluff
Sand Beach
Sand Beach
Sand Beach
Cobble Beach
Cobble Beach
Cobble Beach
Artificial
Cobble Beach
Cobble Beach
Cobble Beach
Cobble Beach
Cobble Beach
Cobble Beach
Cobble Beach
Cobble Beach
Sand Beach
Sand Beach
Sand Beach
Sand Beach
Cobble Beach
Cobble Beach
Cobble Beach
Sand Beach
Sand Beach
Cobble Beach
Cobble Beach
Cobble Beach
Sand Beach
Sand Beach
Sand Beach
Cobble Beach
Cobble Beach
Cobble Beach
Sand Beach
Sand Beach
Sand Beach
Sand Beach
Sand Beach
Sand Beach
Sand Beach
Cobble Beach
Sand Beach
Other
Wetland
Wetland
Wetland
NEARSHORE AREAS OF THE GREAT LAKES 2009
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NOAA/TNC Shoreline Classification
ID Morphology Class
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
!Z
High (>15m) bluff; cohesive, moderately lo highly erodible, generally linear shore, gullied, subject to dramatic cyclical failure due to
groundwater and other processes.
High (> 1 5m) bluff with beach; higher sand content, high to moderate readability, beach may act as protection, subject to dramatic
cyclical failure due to groundwater and other processes.
Low (<15m) bluff; moderate erodibility.
Low (<15m) bluff with beach; moderate erodibility.
Sandy/silty banks; highly erodible.
Clay banks: very cohesive, highly erodible.
Sandy beach/dunes; low to moderate erodibility. depends on sediment budget.
Coarse beach; cobbles, pebbles, boulders.
Baymouth-barrier beaches; wide beaches fronting established wetlands or embayments. overwash and erosion/accretion processes
present.
Bedrock (resistant); igneous/metamorphic rocks.
Bedrock (non-resistant): sedimentary rocks.
Low Riverine/Coastal Plain; flood prone, low to moderate erodibility.
Open Shoreline Wetlands: mostly emergent vegetation.
Semi-protected wetlands; protected by natural features such as baymouth barriers.
Composite: based on different stratigraphy
Artificial; areas where anthropogenic features / structures have totally obscured the natural, geomorphic shoreline.
Unclassified; data unavailable, inaccurate or indecipherable.
Shoreline Cliff
Shoreline Cliff
Shoreline Cliff
Shoreline Cliff
Shoreline Bluff
Shoreline Bluff
Sand Beach
Cobble Beach
Sand Beach
Bedrock Shore
Bedrock Shore
Other
Wetland
Wetland
Other
Artificial
Other
Land Cover
Land cover data (Table A2) were used to identity coastal forests and rock barrens, and as a measure of coastal pressures (i.e.
amount of natural, urban and agricultural land cover).
Table A2. Land Cover.
PLC28
CLASS
Water
Coastal Mudflats
Intertidal Marsh
Supertidal Marsh
Freshwater Coastal Marsh / Inland Marsh
Deciduous Swamp
Conifer Swamp
Open Fen
Treed Fen
Open Bog
Treed Bog
Tundra Heath
Dense Deciduous. Forest
Dense Coniferous. Forest
Coniferous. Plantation
Mixed Forest Mainly Deciduous
Mixed Forest Mainly Coniferous
Sparse Coniferous. Forest
Sparse Deciduous. Forest
Recent Cutovers
Recent Bums
Old Cuts and Burns
Mine Tailings, Quarries, and Bedrock Outcrop
Settlement and Developed Land
Pasture and Abandoned Fields
Cropland
Alvar
Unclassified (Cloud & Shadow)
PLC2000
DESC_
Water - deep clear
Water - shallow / sedimented
Settlement / Infrastructure
Sand / Gravel / Mine Tailings
Bedrock
Mudflats
Forest Depletion - cuts
Forest Depletion - bums
Forest - regenerating depletion
Forest - sparse
Forest - dense deciduous
Forest - dense mixed
Forest - dense coniferous
Marsh - intertidal
Marsh - supertidal
Marsh - inland
Swamp - deciduous
Swamp - coniferous
Fen - open
Fen - treed
Bog - open
Bog - treed
Tundra Heath
NLCD2001
Class_name
Background
Unclassified
Developed. High Intensity
Developed, Medium Intensity
Developed. Low Intensity
Developed, Open Space
Cultivated Crops
Pasture/Hay
Grassland/Herbaceous
Deciduous Forest
Evergreen Forest
Mixed Forest
Scrub/Shrub
Palustrine Forested Wetland
Palustrine Scrub/Shrub Wetland
Palustrine Emergent Wetland
Estuarine Forested Wetland
Estuarine Scrub/Shrub Wetland
Estuarine Emergent Wetland
Unconsolidatfid Shore
Bare Land / Barren Land
Open Water
Palustrine Aquatic Bed
Agriculture - Pasture / abandoned fields
Agriculture - cropland
Other - unknown
Other - cloud / shadow
Key
Natural [ Water ] Unban ] Agricultural [ Unclassified
NEARSHORE AREAS OF THE GREAT LAKES 2009
39
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4.0 Great Lakes Coastal Wetland Ecosystem
State of the Ecosystem
Background
More than 216.000 hectares (534,000 acres) of coastal wetlands are directly influenced by the waters of the Great Lakes. Under the
United States Clean Water Act. the term wetlands means. "Those areas that are inundated or saturated by surface or ground water
at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation
typically adapted for life in saturated soil conditions."
Lake/River
Lake Superior
St Marys River
Lake Huron
Lake Michigan
SI. Ciair River
Lake St. Clair
Detroit River
Lake Erie
Niagara River
Lake Ontario
Upper St. Lawrence River
Total
Area (ha)
• • .
10.790
61.461
44.516
13.642
2.217
592
25.127
196
22.925
8.454
216.54J
Figure 1. Great Lakes coastal wetland distribution and total area by lake and river.
Source: Great Lakes Coastal Wetlands Consortium, http://www.epa.gov/glnpo/solec/sogl2007/4510_CoastalWetlandAreaByType.pdf
The functions of Great Lakes coastal wetlands - biological, chemical, and physical processes that occur naturally within a
wetland - include the storage and cycling of nutrients and organic materials carried by rivers and streams to the Lakes; food web
production; biological productivity; groundwater recharge; stream base flow maintenance; and, habitats for a wide range of Great
Lakes species. Many fish species, for example, depend upon coastal wetlands for some portion of their life cycles. Coastal wetlands
have functions and values including water quality improvement, flood storage, water supply, erosion protection, and fish spawning
habitats.
Water fluctuations are necessary to maintain this highly productive system. Temporary water fluctuations are caused by wind and
"tides" known as seiches. Seasonal fluctuations reflect the yearly hydrologic cycle of the Great Lakes. Multi-year fluctuations are
caused by basinwide. continental or global changes in climate. Coastal wetland plant life is most affected by water fluctuations.
Low water levels expose bottom sediments which allow seeds to germinate. High water levels may flood out vegetation and dilute
NEARSHORE AREAS OF THE GREAT LAKES 2009
40
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nutrient concentrations. In many areas where the natural systems have been highly modified, vegetated coastal wetlands persist
only because of intensive management that may include water level controls.
There are three major categories of coastal wetlands (Table 1). Lacustrine wetlands are controlled directly by the waters of the
Great Lakes. They are affected by lake level fluctuations, nearshore currents, seiches and ice scour. Riverine wetlands occur in
rivers, tributaries and connecting channels that flow into or between the Great Lakes. Barrier protected wetlands have become
separated from the Great Lakes by a barrier beach or other barrier feature. The barriers protect the wetland from the waves.
Five different types of vegetation can be found in Great Lakes coastal wetlands. Floating plants may be rooted under water, but
have leaves that float on the surface. Submerged plants are rooted under water and grow entirely underwater. Emergent plants
have roots that might be underwater, but grow and flower above the surface of the water. Wet meadow vegetation is less tolerant of
Table 1. Great Lakes coastal wetland classification system.
Source: Great Lakes Coastal Wetland Consortium.
in
Types of Lacustrine Wetlands and Their Definitic
Types of Riverine Wetlands and
Their Definitions
Types of Barrier
Enclosed Wetlands
and Their Definitions
Lacustrine Wetlands
Controlled directly by waters of the Great Lakes and are strongly affected by lake-level fluctuations, nearshore currents, seiches
and ice scour
Open lacustrine
wetlands
Protected lacustrine
wetlands
• These lake-based wetlands
are directly exposed to nearshore
processes with little or no physical
protection by geomorphic features.
• This results in little accumulation of
sediment vegetation development to
relatively narrow nearshore bands.
• These are also a lake-based
system, but characterized by increased
protection by bay or sand-spit
formation.
• This protection results in increased
sediment accumulation, shallower
off-shore profiles, and more extensive
vegetation development.
Open shoreline
wetlands
Open
embayment
wetlands
Protected
embayment
wetlands
Sand-spit
embayment
wetlands
• These are typically characterized by an erosion
resistant substrate of either rock or clay, with occasional
patches of mobile substrate.
• The resultant expanse of shallow water serves to
dampen waves which may result in sand bar development
at some sites.
• There is almost no organic sediment accumulation in
this type of environment.
• They can occur on gravel, sand, and clay (fine)
substrate.
• The embayments are often quite large — large enough
to be subject to storm-generated waves and surges and to
have established nearshore circulation systems.
• They can be completely vegetated with emergent or
submergent vegetation.
• These project along the coast and create and protect
shallow embayments on their landward side.
• Spits often occur along gently sloping and curving
sections of shoreline where there is a positive supply of
sediment and sand transport is not impeded by natural of
man-made barriers.
• These wetlands are typically quite shallow.
Riverine Wetlands
Occur in rivers and creeks that flow into or between the Great Lakes
Open - drowned river
mouth wetlands
Barred - drowned river
mouth wetlands
Connecting channel
wetlands
Deltas
• These wetlands may not have barriers at their mouth, nor do they have a lagoon or small lake present where they
meet the shore.
• The wetlands along these streams occur along the river banks and their plant communities are growing on deep
organic soils.
• These wetlands maintain a relatively constant connection to the lakes.
• These wetlands include the large connecting rivers between the Great Lakes; the St. Marys, St. Clair, Detroit,
Niagara, and St. Lawrence Rivers.
• They are distinctive from the other large river wetlands (drowned river mouth) by their general lack of deep organic
soils and their often strong currents.
• These are formed of alluvial materials, both fine and coarse, and support extensive wetlands that extend out into the
Great Lake or connecting river.
Barrier Enclosed Wetlands
Originated from either coastal or fluvial processes. However, due to coastal processes the wetlands have become separated from
the Great Lakes by a barrier beach or other barrier feature. These wetlands are protected from wave action but may be connected
directly to the lake by a channel crossing the barrier.
Barrier beach lagoon
wetlands
Swale complexes
• These wetlands form behind a sand barrier.
• Because of the barrier, there is reduced mixing of Great Lakes waters and the effects of coastal processes are
minimized.
• These occur between re-curved fingers of sand spits and those that occur between relict beach ridges.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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flooding and represents a transition from wetland to terrestrial. The shrub zone contains woody plants that grow above the water
line, but is influenced by periodic flooding.
A diversity of animals inhabits coastal wetlands. Phytoplankton is at the base of the food chain. Macroinvertebrates such as
insects, snails, molluscs and worms cycle nutrients through the system by breaking down coarse vegetation; they are also food for
fish and birds. Ninety percent of the more than 200 species of Great Lakes fish spend some part of their life cycle in Great Lakes
coastal wetlands. Fish such as northern pike (Esox lucius), yellow perch (Perca flavescens) and bowfin (Amia calvd) spawn in
coastal marshes. Birds, reptiles and amphibians use coastal wetlands as resting, feeding and nesting habitat.
This report summarizes the environmental status and trend of Great Lakes coastal wetlands. It provides details of coastal wetland
indicator reports and outlines current and probable future pressures on coastal wetland resources. It outlines possible management
actions needed to monitor, protect and restore, and manage Great Lakes coastal wetlands. And it describes how assessing the status
and trend of coastal wetlands has changed since SOLEC 1996.
Status and trend summary \
The status of the Great Lakes coastal wetland system is mixed and the trend is deteriorating due to habitat loss and deterioration,
invasive species, water level stabilization, and contaminants. Declines in populations of species that use wetlands almost exclusively
for breeding, combined with an increase in some wetland edge and generalist species, suggest changes in wetland habitat conditions
may be occurring. The status and trend are based on observations or best professional judgment and on indicator reports.
• Over the past decade, statistically significant declining trends were detected for American toad (Bufo americanus), bullfrog
(Rana catesbeiand), chorus frog (Pseudacris triseriata), green frog (Rana clamitans), and northern leopard frog (Rana
pipiens). Wetland bird species with significant basinwide declines were American coot (Fulica americana), black tern
(Chlidonias niger), blue-winged teal (Anas discors), common grackle (Quiscalus quiscula), common moorhen (Gallinula
chloropus), least bittern (Ixobrychus exilis), undifferentiated common moorhen/American coot, northern harrier (Circus
cyaneus), pied-billed grebe (Podilymbus podiceps), red-winged blackbird (Agelaius phoeniceus), sora (Porzana Carolina),
tree swallow (Tachycineta bicolor), and Virginia rail (Rallus limicold).
• Mechanical disturbance of coastal sediments appears to be one of the primary vectors for introduction of non-native
invasive species to coastal wetlands. Intact wetlands, on the other hand, may be a refuge for native fishes, at least with
, respect to the influence of round gobies (Neogobius melanostomns).
• A disturbing trend is the expansion of frogbit (Hydrocharis morsus-ranae); it is a floating plant that forms dense mats
capable of eliminating submergent plants. Frogbit is found from the St. Lawrence River and Lake Ontario westward into
Lake Erie.
• With diet the primary source of exposure, contaminants such as polychlorinated dioxins, furans, polychlorinated
biphenyls (PCBs) measured in snapping turtles (Chelydra serpentina) are persistent and bioaccumulative. This indicates
that contamination still persists throughout the aquatic food web.
• In 2007, low Lake Superior water levels resulted in devastation of Kakagon Sloughs (Wisconsin) wild rice (Zizania
palustris) beds. Bad River Tribe natural resource personnel reported that many wild rice beds resembled mud flats. Low
water levels could lead to an influx of non-native species such as purple loosestrife (Lythrum salicarid).
• The status of Georgian Bay and the North Channel coastal wetlands of Lake Huron are good based on McMaster
University researchers' evaluation of more than 100 wetlands. Some degradation was noted in southeastern Georgian
Bay due to anthropogenic disturbances.
• Water level control in Lake Ontario has resulted in a decrease in plant and animal diversity in coastal wetlands. The
International Joint Commission has completed a five-year study on the impacts of water level controls on shoreline
habitats and properties, shipping, and small boat use.
Status and trend by indicator
The SOLEC 2004 paper The Great Lakes Indicator Suite: Changes and Progress 2004, contains descriptions of 13 indicators
deemed relevant to determine the status and trend of Great Lakes coastal wetlands. Based on the work of the Durham coastal
wetland managers and other Great Lakes coastal wetland scientists, previous SOLEC authors, the Coastal Wetland Consortium,
and the Great Lakes Environmental Indicators (GLEI) collaborators, six coastal wetland indicators are now recommended
to effectively and efficiently monitor Great Lakes coastal wetlands. In addition, other chemical and physical coastal wetland
information such as turbidity, conductivity, phosphorus, and nitrogen, will be collected to help interpret indicator data.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Three indicators suggested in the 2004 report are not considered specific to the coastal wetland indicator suite. Contaminants in
Snapping Turtle Eggs (4506), Phosphorus and Nitrogen Levels (4860), and Effect of Water Levels Fluctuations (4861) are associated
with coastal wetlands, however are broader in the context of overall ecosystem health and should therefore not be included in the
coastal wetland suite. Four indicators—Coastal Wetland Restored Area by Type (4511), Sediment Flowing into Coastal Wetlands
(4516), Human Impact Measures (4864), and Land Cover Adjacent to Wetlands (4963)—are not feasible to monitor at this time.
The recommendation is to eliminate these indicators. One other indicator, Sediment Available for Coastal Nourishment (8142), was
suggested after the 2004 report and is applicable to the entire Great Lakes shoreline so should not be considered solely a coastal
wetland indicator.
The names for the six indicators below have changed since the State of the Great Lakes 2007 report (Environment Canada and U.S.
Environmental Protection Agency 2007). More detailed information is found in each indicator's status and trend report.
Extent and composition of coastal wetlands (SOLEC indicator 4510): mixed, deteriorating
The status of this indicator has not been updated since the State of the Great Lakes 2005 report. One conclusion of the 2005 report
was that wetlands continue to be lost and degraded, yet the ability to track and determine the extent and rate of this loss in a
standardized way is not yet feasible. A GIS database providing the first spatially explicit seamless binational summary of coastal
wetland distribution in the Great lakes system was completed in 2004. Coastal wetlands totaling 216,743 hectares (535,584 acres)
were identified up to Cornwall, Ontario. However, due to existing data limitations, estimates of coastal wetland extent, particularly
for the upper Great Lakes are acknowledged to be incomplete. Despite significant losses in some regions, the Lakes and rivers still
support a diversity of wetland types. Stressors to coastal wetlands continue to contribute to the loss and degradation of coastal
wetland area including filling, dredging, draining for conversion to other uses, shoreline modification, water level regulation, and
sediment and nutrient loading from watersheds.
The 2005 report also concluded that many of the pressures result from direct human actions and therefore, with proper consideration
of the impacts, can be reduced. Because of growing concerns around water quality and supply, which are key Great Lakes
conservation issues, and the role of wetlands in flood attenuation, nutrient cycling and sediment trapping, wetland changes need
to be monitored closely.
Coastal wetland invertebrate communities (SOLEC indicator 4501): not assessed
Development of this indicator is still in progress. In 2002, the Great Lakes Coastal Wetlands Consortium conducted extensive
surveys of wetland invertebrates of the four lower Lakes. The data are not entirely analyzed to date. However, the Consortium
adopted an Index of Biotic Integrity that was applied in wetlands of northern Lake Ontario. Physical alteration and eutrophication
continue to be a threat to coastal wetland invertebrates due to promotion of non-native vegetation and destruction of plant
communities as well as changes to the natural hydrology.
Coastal wetland fish communities (SOLEC indicator 4502): not assessed
Lakes Erie and Ontario tend to have more wetlands containing cattail communities and therefore, fish communities of lower richness
and diversity. The seven wetlands sampled in Lake Superior contained relatively unique vegetation types so fish communities of
these wetlands were not directly compared with those of wetlands of other lakes. There appear to be no wetlands in the U.S. portion
of Lake Erie that have experienced minimal anthropogenic disturbance. Comparatively, northern Lakes Huron and Michigan
wetlands have relatively high quality coastal wetland fish communities.
Bluntnose minnows (Pimephales notatus) and johnny darters (Etheostoma nigrum) are almost absent from Lake Michigan's
lower bay wetland sites. Species associated with plants and clearer water—rock bass (Ambloplites sp.), sand shiners (Notropis
stramineus), and golden shiners (Notemigonus crysoleucas)—are present in upper bay samples, but absent from lower bay samples.
In 2003, there were no alewives (Alosa pseudoharengus) or gizzard shad (Dorosoma cepedianum) at an upper Green Bay site.
Likewise, the fish assemblage structure in Cootes Paradise, a highly degraded wetland in Lake Ontario, is very different from
other less degraded wetlands analyzed in one study. Water quality is one factor in determining plant communities and that in turn
influences fish community structure. Groups of fish species in reference wetlands tend to have similar water temperature and
aquatic productivity preferences.
Based on intensive fish sampling prior to 2003 at more than 60 sites spanning all the Great Lakes, round gobies have not been
sampled in large numbers at any wetland or have been a dominant member of any wetland fish community. Therefore, it seems
likely that wetlands may be a refuge for native fishes, at least with respect to the influence of round gobies. There is little information
NEARSHORE AREAS OF THE GREAT LAKES 2009
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on the habitat preferences of the tubenose goby (Proterorhinus marmoratus) within the Great Lakes with the exception of studies
on the Detroit River. Because this goby shares habitats with fishes from many different habitats, however, it is suggested that the
tubenose goby will expand its geographic range within the Great Lakes.
Ruffe (Gymnocephalus cernuus) have never been found in high densities in coastal wetlands anywhere in the Great Lakes. In one
study it was concluded that coastal wetlands in western Lake Superior provide a refuge for native fishes from competition with
ruffe. The mudflat-preferring ruffe avoids wetland habitats due to foraging inefficiency in dense vegetation that characterizes
healthy coastal wetland habitats. Therefore, further degradation of coastal wetlands could lead to increased dominance by ruffe
in shallow water habitats.
Grasshead carp (Ctenopharyngodon idellus), bighead carp (Hypophthalmichthys nobilis), and silver carp (Hypophthalmichthys
molitrix) have escaped aquaculture operations and are now in the Illinois River and migrating toward the Great Lakes through
the Chicago Sanitary Canal. These species represent a substantial threat to food webs in wetlands and nearshore habitats with
macrophytes. \
Coastal wetland amphibian communities fSOLEC indicator 4504): mixed, deteriorating
Amphibian data have been collected at 548 routes across the Great Lakes basin since 1995. Thirteen species were recorded during
the 1995-2007 period. Spring peeper (Pseudacris crucifer) was the most frequently detected species. Spring peeper populations
are increasing. Green frog was detected in more than half of the survey stations. Grey treefrog (Hyla versicolor), American toad,
and northern leopard frog were common. Statistically significant declining trends were detected for American toad, bullfrog,
chorus frog, green frog, and northern leopard frog. Anecdotal and research evidence suggests that wide variations in occurrence
of many amphibian species at a given site is a natural and ongoing phenomena.
Coastal wetland bird communities (SOLEC indicator 4507): mixed, deteriorating
Since 1995, Marsh Monitoring Program volunteers have collected bird data at 508 discrete routes across the Great Lakes basin.
Fifty six bird species that use marshes for feeding, nesting or both throughout the Great Lakes basin were recorded. The red-
winged blackbird was the most commonly recorded non-aerial foraging bird observed followed by the swamp sparrow (Melospiza
georgiana), marsh wren (Cistothorus palustris), and yellow warbler (Dendroica petechia). Among birds that nest exclusively in
marsh habitats, the most commonly recorded species was marsh wren followed by Virginia rail, common moorhen, pied-billed
grebe, American coot and sora. Among species that typically forage in the air above marshes, tree swallow and barn swallow
(Hirundo rustica) were the two most commonly recorded bird species.
Species with significant basinwide declines were American coot, black tern, blue-winged teal, common grackle, common moorhen,
least bittern, undifferentiated common moorhen/American coot, northern harrier, pied-billed grebe, red-winged blackbird, sora,
tree swallow, and Virginia rail. Statistically significant basinwide population increases were observed for common yellowthroat
(Geothfypis trichas), mallard (Anas platyrhynchos), northern rough-winged swallow (Stelgidopteryx serripennis), purple martin
(Progne subis), trumpeter swan (Cygnus buccinator), willow flycatcher (Empidonax traillii), and yellow warbler. American bittern
(Botaurus lentiginosus) and marsh wren populations did not show a significant trend in abundance indices from 1995 through
2005. Differences in habitats, regional population densities, timing of survey visits, annual weather variability and other factors
will likely interplay with water levels to explain variation in wetland dependent bird populations.
Coastal wetland plant communities (SOLEC indicator 4862): mixed, undetermined
The state of the wetland plant community is quite variable, ranging from good to poor across the Great Lakes basin. There is
evidence that the plant component in some wetlands is deteriorating in response to extremely low water levels in some of the Great
Lakes, but this deterioration is not seen in all wetlands within these lakes. In general, there is slow deterioration in many wetlands
as shoreline alterations introduce non-native species. Trends in wetland health based on plants have not been well established.
Turbidity of the southern Great Lakes has reduced with the expansion of zebra mussels (Dreissena polymorpha), resulting in
improved submergent plant diversity in many wetlands. However, in Saginaw Bay, Green Bay, and Lake Ontario, agricultural
sediments have resulted in highly turbid waters which support few or no submergent wetland plants.
In the southern Great Lakes, almost all wetlands are degraded by either water level control, nutrient enrichment, sedimentation,
or a combination of these factors. Probably the strongest demonstration of this is the prevalence of broad zones of cattails (Typha
sp.), reduced submergent diversity and coverage, and prevalence of non-native plants. Low water conditions have resulted in the
NEARSHORE AREAS OF THE GREAT LAKES 2009
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almost explosive expansion of reed in many wetlands, especially in Lake St. Clair and southern Lake Huron, including Saginaw
Bay. In most Great Lakes urban settings, almost complete wetland loss has occurred along the shoreline. Shoreline hardening is
eliminating wetland vegetation. Mechanical alteration of the shoreline is fostering the introduction of non-native species.
A disturbing trend is the expansion of frogbit, a floating plant that forms dense mats capable of eliminating submergent plants,
found from the St. Lawrence River and Lake Ontario westward into Lake Erie. This expansion will probably continue into all
or many of the Great Lakes. It appears that undisturbed marshes are not easily colonized by non-native species such as purple
loosestrife and reed canary grass (Phalaris arundinaced). As these species become locally established, seeds or fragments of plant
may be able to establish when water level changes create appropriate sediment conditions. The worst wetland invasive species is
the asian carp, whose mating and feeding result in loss of submergent vegetation in shallow marsh waters.
Pressures
Future pressures on the coastal zone will likely include continuing loss and degradation of important coastal wetlands, water
level decrease or stabilization, sedimentation, contaminant and nutrient inputs, and continued invasion of non-native plants and
animals. Human-induced global climate change has the potential to result in severe changes in coastal wetland habitats. The
following summary of pressures on the coastal wetland system is based on an analysis by indicator report authors.
Agriculture
Agriculture degrades wetlands in several ways, including nutrient enrichment from fertilizers, increased sediments from erosion,
increased rapid runoff from drainage ditches, introduction of agricultural non-native species such as reed canary grass, and
destruction of inland wet meadow zone by plowing and diking, and addition of herbicides. In the southern lakes, Saginaw Bay, and
Green Bay, agricultural sediments have resulted in highly turbid waters which support few or no submergent plants.
Urban development
Urban development degrades wetlands by hardening shoreline, filling wetland, adding a broad diversity of chemical pollutants,
increasing stream runoff, adding sediments, and increasing nutrient loading from sewage treatment plants. In most urban settings,
almost complete wetland loss has occurred along the shoreline.
Residential shoreline development
Along many coastal wetlands, residential development has altered wetlands by nutrient enrichment from fertilizers and septic
systems, shoreline alterations for docks and boat slips, filling, and shoreline hardening. Agriculture and urban development are
usually less intense than local physical alteration which often results in the introduction of non-native species. Shoreline hardening
can completely eliminate wetland vegetation.
Mechanical alteration of shoreline
Mechanical alteration takes a diversity of forms, including diking, ditching, dredging, filling, and shoreline hardening. With all of
these alterations, non-native species are introduced by construction equipment or in introduced sediments. Changes in shoreline
gradients and sediment conditions are often adequate to allow non-native species to become established.
Introduction of non-native species
Non-native species are introduced in many ways. Some were purposefully introduced as agricultural crops or ornamentals,
later colonizing in native landscapes. Others arrived as weeds in agricultural seed. Increased sediment and nutrient enrichment
allow many of the worst aquatic weeds to out-compete native species. Most of the worst non-native species are either prolific
seed producers or reproduce from fragments of root or rhizome. Non-native animals have also been responsible for increased
degradation of coastal wetlands. One of the worst invasive species has been asian carp, whose mating and feeding result in loss of
submergent vegetation in shallow marsh waters.
1996 - 2008: Changes in assessing coastal wetlands
The SOLEC 1996 paper, Coastal Wetlands of the Great Lakes (Maynard and Wilcox 1997), presented an overview of coastal
wetland ecology, ecological functions and values, and stressors. The authors suggested the development of coastal wetland
indicators in the following categories: physical and chemical, individual and population level, wetland community, landscape,
and social and economic. The status of coastal wetlands based on expert information was given for each of the Great Lakes,
NEARSHORE AREAS OF THE GREAT LAKES 2009
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the St. Mary's River, St. Clair River, Lake St. Clair, Detroit River, Niagara River, and St. Lawrence River. Among the authors'
conclusions were the following management challenges:
• "There is no comprehensive inventory and evaluation of Great Lakes coastal or even inland wetlands."
• In the U.S., "Individual states have also completed wetland inventories and evaluations, however methodologies are not
consistent and the level of detail and amount of field-based data varies."
• "Work has been initiated to develop indicators for wetland degradation and to choose monitoring sites and appropriate
monitoring strategies. However, there is no international consensus on these matters."
The background paper for SOLEC 1998, Biodiversity Investment Areas, Coastal Wetland Ecosystems (Chow-Fraser and Albert
1998), identified and described a multitude of wetland inventory databases and classification systems in use throughout the basin.
The Great Lakes shoreline was divided into eco-reaches based on fish and avifaunal uses and diverse coastal wetlands identified.
The authors concluded: "We recognize that the value of the eco-reach must reflect the distribution of wetlands as well as size,
distribution and quality...Unfortunately, information regarding\wetland size and quality is incomplete, and we were not able to
conduct a systematic comparison of eco-reaches with respect to mese parameters."
Although coastal wetlands have critically important ecological values and functions, coastal wetland data are not available
binationally or basinwide; no one entity has the responsibility to oversee the coordination of coastal wetland data. The conclusion:
a binational monitoring program is needed to assess the health of Great Lakes coastal wetlands, an integral part of the Great Lakes
basin ecosystem.
In 2000, the U.S. EPA Great Lakes National Program Office funded the creation of the Great Lakes Coastal Wetland Consortium
to expand the coastal wetland monitoring and reporting capabilities of the U.S. and Canada under the Great Lakes Water Quality
Agreement. The Consortium was coordinated by Great Lakes Commission staff and consisted of scientific and policy experts
drawn from key U.S. and Canadian federal agencies, state and provincial agencies, non-governmental organizations, and other
interest groups with responsibility for coastal wetlands monitoring. Approximately two dozen agencies, organizations and
institutions were brought into the Consortium as Project Management Team members. In addition, other members were brought
in as small project teams formed to address discrete project elements and pilot studies.
The purpose of the Consortium was to design a long term, binational coastal wetland monitoring program. Indicators suggested in
the SOLEC papers were evaluated and protocols tested. In early 2008, a final report detailed indicators, protocols for monitoring,
and costs. Major accomplishments include:
• A map of the 217,000 hectares (536,219 acres) of known coastal wetlands;
• A new classification system consisting of three major categories: lacustrine, riverine, and barrier-protected that was then
applied to the mapped coastal wetlands;
• Field-tested sampling protocols;
• A statistical sampling design; and,
• A database that will house future data.
In 2002 and 2003, the initial work of the Consortium was field tested at 15 sites in the Regional Municipality of Durham on the north
shore of Lake Ontario. The project was designed to improve coordination among stakeholders, standardize monitoring methods in
order to compare results among wetlands and watersheds, and improve the condition of wetlands in this highly urbanized region
through support of meaningful management decisions. In turn, the Durham Region Coastal Wetland Monitoring Project provides
a blueprint for implementing a basinwide coastal wetland monitoring program.
A U.S. project, Great Lakes Environmental Indicators (GLEI), researched the development of an integrated set of environmental
indicators to assess the condition of the shoreline, including coastal wetlands. This project combined field and existing data to link
stressors with environmental indicators and recommended a suite of hierarchically-structured indicators. Consortium and GLEI
project partners worked together to determine coastal wetland monitoring protocols that are feasible and cost effective yet result
in useful data.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Management Implications
Over the past seven years, a group of dedicated Great Lakes coastal wetlands experts mapped the extent of Great Lakes coastal
wetlands; created a coastal wetland classification system and applied it to the mapped wetlands; developed an indicator sampling
design and process; and built a database. The pieces are in place to implement a long-term coastal wetland monitoring program.
Data from this program will, over time, improve coastal wetland system assessment and allow management agencies to better
target protection and restoration of coastal wetland resources. The management challenge is to provide the resources needed to
monitor Great Lakes coastal wetlands over the long term.
Comments from the Authors
Authors of the indicator papers have recommended the following actions to monitor, protect and restore, and manage Great Lakes
coastal wetlands.
Monitor
• Continue to monitor coastal wetland in order to determine impacts from water level stabilization, sedimentation,
contaminant and nutrient inputs, climate change and invasion of exotic species.
Maintain high quality wetland habitat as well as associated upland areas adjacent to coastal wetlands.
• Monitor amphibians according to a five-year rotational cycle in order to sufficiently monitor noteworthy changes in
population indices and trends in species occurrence or relative abundance to environmental factors.
• Monitor the contaminant status of snapping turtles on a regular basis across the Great Lakes basin where appropriate.
Once the usefulness of the indicator is confirmed, a U.S. program that is complementary to the Canadian program is
required to interpret basinwide trends
• Monitor the response of reed canary grass to rising water levels.
• Monitor following disturbance of coastal sediments to reduce new introductions of non-native plants.
Protect and restore
• Address impacts detrimental to wetland health such as water level stabilization, invasive species and inputs of toxic
chemicals, nutrients and sediments.
• Conserve and restore wetland habitats to ensure their functioning.
Incorporate buffer strips along steams and drains to mitigate the effects of agriculture and urban sediments on coastal
wetlands.
• Reduce algal blooms by more effectively applying fertilizer.
• Establish regional goals and acceptable thresholds for species-specific abundance indices and species community
compositions.
• Thoroughly clean equipment to eliminate non-native seed sources.
• Verify the relationships between wetland-adjacent land cover and the functions of coastal wetlands.
Uniformly measure adjacent land cover field parameters across the region to determine accurate information.
Acknowledgments
Authors:
Karen M. Rodriguez, U.S. Environmental Protection Agency, Great Lakes National Program Office
Krista Holmes, Environment Canada
Numerous scientists and managers have had input to the development of coastal wetland indicators. For a list of Great Lakes
Coastal Wetlands Consortium contributors, please see the "Acknowledgments" section in the "Great Lakes Coastal Wetlands
Monitoring Plan" report at http://www.glc.org/wetlands/final-report.html.
Information Sources
Chow-Fraser, P., and Albert, D.A. 1998. Biodiversity Investment Areas, Coastal Wetlands Ecosystems. Identification of "Eco-
reaches" of Great Lakes Coastal Wetlands that have high biodiversity value. A discussion paper for the State of the Lakes
Ecosystem Conference, 1998. Chicago, IL: U.S. Environmental Protection Agency, and Burlington, ON: Environment Canada.
http://www.epa.gov/glnpo/solec/solec_1998/Coastal_Wetland Ecosystems_Biodiversity_Investment_Areas.pdf
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Chow-Fraser, P., McNair, S., Seilheimer, T., Wei, A., Kostuk, K., and Croft, M. 2006. Ecosystem-based assessment of the quality
offish habitat in coastal wetlands of Eastern Georgian Bay and the North Channel. Hamilton, ON: McMaster University.
March 2006.
Environment Canada and U.S. Environmental Protection Agency. 2007. State of the Great Lakes 2007. Chicago, IL: U.S.
Environmental Protection Agency, and Burlington, ON: Environment Canada.
Grabas, G. 2004. Durham Region Coastal Wetlands, Baseline Conditions and Study Findings. Downsview, ON: Environment
Canada. http://www.cloca.com/resources/DRCWMP-2004%20Fact%20Booklet.pdf
Great Lakes Coastal Wetlands Consortium. 2008. Great Lakes Coastal Wetlands Monitoring Plan. Ann Arbor, MI: Great Lakes
Commission. March 2008. http://www.glc.org/wetlands/final-report.html
Great Lakes Environmental Indicators Project. 2006. Duluth, MN: Natural Resources Research Institute, University of Minnesota
Duluth. http://glei.nrri.umn.edu/default/
Lake Huron Binational Partnership 2008 - 2010 Action Plan. 2008. Chicago: U.S. Environmental Protection Agency. June 2008.
http://www.epa.gov/glnpo/lamp/lh_2008/index.html
Lake Ontario Lakewide Management Plan 2008. 2008.\Chicago: U.S. Environmental Protection Agency. June 2008.
http://www.epa.gov/grnpo/lamp/lo_2008/lo_2008_5.pdf)
Maynard, L., and Wilcox, D. 1997. Coastal Wetlands. A discussion paper for the State of the Lakes Ecosystem Conference 1996.
Chicago, IL: U.S. Environmental Protection Agency, and Burlington, ON: Environment Canada. October 1997.
Rasmussen, Charlie Otto. 2007. Parched for water, Ojibwe Country feels impact. Mazina'igon Fall 2007. Great Lakes Indian Fish
and Wildlife Commission. http://www.glifwc.org/publications/Mazinaigan/fall2007.pdf
NEARSHORE AREAS OF THE GREAT LAKES 2009
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5.0 NEARSHORE WATERS OE THE GREAT LAKES
5.1 Nutrients and the Great Lakes Nearshore, Circa 2002-2007
Overview
In the last 10-20 years, there has been increasing concern about ecological changes in the nearshore region of the Great Lakes.
Effects are directly related to changes in nutrient loading and biogeochemical interactions that involve invasive dreissenid mussels,
water quality, and benthic macroalgal growth. Edsall and Charlton (1997) noted some early trends related to mussels, Cladophora.
nutrients, chlorophyll, and light in their background paper prepared tor SOLHC 1996. This chapter revisits the themes of Edsall and
Charlton (1997). using data from the first decade of the 2000s. Some previously-noted trends have continued. For example, nutrient
concentrations often appear higher in nearshore waters, but this trend depends on the nutrient form and the lake being considered.
Recent lower lake studies report no real distinction between nearshore and offshore in terms of nutrients and chlorophyll at specific
locations. Such studies suggest that decreases in nearshore chlorophyll and nutrient concentrations involve mussels and have lead
to renewed growth of Cltulophoru.
While we have some information for a nearshore assessment, it is largely ml hoc. This chapter has relied primarily on a large-scale
research project supplemented with data from regular offshore monitoring, and information from selected recent site-specific
research. Water quality protection would benefit from information collected by a regular, consistent, and Great Lakes-wide
monitoring to include the nearshore: one such planned effort is described briefly. Additionally, there are some powerful mapping
technologies being evaluated to assist with assessment.
Slate of the Kcosystem
In 1996. Edsall and Charlton (1997) reported that there were few data to assess nutrient status that were explicitly from nearshore
zone sampling. Nearshore nutrient impressions were largely limited to observations of local spatial trends from a few site-specific
studies and some temporal trends at a set of Canadian water intake locations (later summari/ed in Nicholls el til. 1999). Lacking
a systematic information base for the nearshore. Edsall and Charlton (1997) used data from existing open water surveillance and
monitoring programs (Environment Canada [EC] and U.S EPA Great Lakes National Program Office [GLNPO] 2007) to describe
decadal trends in the lakes leading up to the mid-1990s. Their impressions of the mid-1990s included the following related to the
nearshore:
(I) Nutrients and chlorophyll tended to be elevated closer to shore and decreased moving offshore.
(2) Exceedance of Total Phosphorus (TP) guidelines (10-15 ug I.) were noted in Lake Ontario (nearshore) and Lake Erie
(nearshore and offshore).
(3) The levels of nearshore chlorophyll a relative to TP were low after dreissenid mussel infestation (which occurred in late
1980s in Lake Erie, thereafter in other lakes), compared to observations at those same locations pre-mussel invasion.
(4) Long-term declines in TP and chlorophyll at shallow (-3-17 m) water intake stations were evident for all the lakes from
the 1970s through the late 1980s. Some chlorophyll declines may have continued into the 1990s, whereas further TP
declines were less apparent.
(?) The reappearance of the attached benthic (bottom-dwelling) alga C/M/oplioni in shallow waters was noted in the mid/
late 1990s. ('hidophora was a problem in former decades, prior to Phosphorus (P) abatement, when excessive growth and
drift to shorelines lead to widespread problems of beach fouling/odor.
This chapter revisits these themes, using recent information. As initial background for SOLEC 2008, this is not an exhaustive
review, but is intended to capture the flavor of conditions in the nearshore during the current decade.
Assessment
Basis
There has been no regular or consistent monitoring and assessment of Great Lakes coastal systems, including the shallow open
nearshore. semi-enclosed embayments. or coastal wetlands. The focus of this chapter is open nearshore1 waters, not excluding larger
I There are a variety of operational definitions of nearshore (cf. U.S. hl'A 1442. Hdsall and Charlton l'«7. Mackey and (iotbrlh 2(105). The shoreward extent
is variously considered, especialh as to hou far it should extend up tributary im.mhs and whether small, semi-enclosed embaymenls should be included or
considered a separate class of coastal system. The offshore "boundary" has been considered to he a certain depth or distance from shore, or combination
thereof: usually, a deepest extent to about lO-.W m (to include intersection of the summer ihermocline with the bottom) has been considered. The depth
NEARSHORE AREAS OF THE GREAT LAKES 2009
49
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bays like Saginaw Bay and Green
Bay. To my knowledge, Gregor and
Rast (1979, 1982) last attempted
a quasi-synoptic examination of
nearshore trophic status, including
nutrients, using data from the mid-
1960s to early 1970s. Their final
evaluation was limited to Canadian
shorelines (Gregor and Rast 1982),
due to adequacy of data. In the last
30-1- years, there have been many
periodic research efforts, but these
usually have focused on a given site or
basin/region within a lake. It has been
rare to have comparable information
available across the nearshore of the
whole region (Nicholls et al. 1999).
A recent analysis of gaps in Lake
Michigan monitoring concluded
there were limited, disconnected
efforts in nearshore monitoring
(Lake Michigan Pilot Study 2008).
Most recently, there have been
some directed efforts to take a
more dedicated look at nearshore
waters as a component of lake-wide
assessment efforts; these include
the recent Lake Erie Millennium
assessment efforts, and a binational
lower food web assessment in Lake
Superior (2005/2006) as part of
continuing efforts at internationally-
coordinated monitoring in each
lake on a five-year rotating basis.
Nearshore research has increased, so
the information base is expanding,
even if it is not yet systematic and
consistent.
LAKE
Superior*
Huron **
Michigan
Erie
Ontario
TP (ug/L)
ISRP^gA.)]
6.43 (
-------
schemes within and across the lakes (cf. Danz el ul. 2(105.
2007): data provide a representative range and capture average
conditions well enough to make some example comparisons
within and across the lakes. Nearshore data are contrasted to
offshore nutrient concentrations measured in the same time
period in the ongoing U.S. EPA GLNPO monitoring program.
Simple use of these data here is intended to provide a current
perspective, and is not a detailed statistical analysis.
Concentrations aiui vuriuhilitv
The summaries of nutrient and chlorophyll a for both nearshore
and offshore waters across the Great Lakes (Tables 1. 2) show-
values and ranges consistent with other recent reports for
various specific locations (cf. Lake Erie [Davies and Heck>
2005. Higgins el ai. 2006. Depew et al. 2006. Smith el ul.
2007]: Lake Ontario [Hall et al. 2003. NYSDEC 2005. Hecky.
et ul. 2007. Holeck ct ul. 2008. Malkin et al. 2008]: Lake
Nearshore o Offshore
• L
.
* * *
TP (ug/L) from 2001-2007
i Nearshore a Offshore
0.1 to 1-2-3-4-5-6-7-8-
0.99 199 2.99 3.99 4.99 5.99 6.99 799 8.99
Chlorophyll a (ng/L) from 2001-2006
Figure 1. Frequency distribution of summer Total
phosphorus (ug/L) and chlorophyll a (ug/L) in Lake Erie, in
the 2001-2007 period.
Dotted lines are guidelines for Lake Erie, 10 ug/L or 15
ug/L depending on the basin. The offshore mean was
slightly <10 pg/L and the nearshore mean was >15 ug/L.
There is no guideline for chlorophyll a.
Source: U.S. EPA. Mid-Continent Ecology Division and U.S. EPA. GLNPO
LAKE
Superior
Huron
Michigan
Erie
Ontario
Nearshore
(n=207)
Offshore
(n=111-130)
Nearshore
(n=89)
Offshore
(n=84-98)
Nearshore
(n=130)
Offshore
(n= 66-74)
Nearshore
(n=48)
Offshore
(n=140)
Nearshore
(n=60)
Offshore
(n=48-56)
TP
48%
69%
73%
28%
83%
27%
82%
111%
155%
19%
NO,
14%
31%
24%
10%
22%
13%
46%
51%
27%
22%
Silicate
13%
7%
24%
19%
56%
54%
52%
95%
193%
62%
Chloride
26%
6%
29%
7%
25%
3%
21%
19%
14%
3%
Chlorophyll
106%
38%
163%
46%
69%
36%
100%
84%
55%
36%
Table 3. Variability (coefficient of variation, CV%) compared for
nearshore and offshore data summaries for the Great Lakes
during 2001-2007 period.
Sources: U.S. EPA. Mid-Continent Ecology Division and U.S. EPA. GLNPO
Michigan [Carrick et ul. 2001]: Lake Huron [Fahnenstiel et al.
2008]). In general, concentration ranges are wide within each lake
and the concentration ranges of nearshore and offshore locations
are overlapping: nearshore and offshore locations typically have
similar low-end concentrations near or below detection limits for
some analyses. It is usually the case that nutrient and chlorophyll
variability is higher in the nearshore (Table 3). which reinforces a
classic vie\\.
For many analytes and most lakes, the mean and overall
distribution of samples is biased to higher levels within the
nearshore (Fig. 1) and the average levels thus tend to be higher
in shallower nearshore waters, again reinforcing the classic vie\\.
This is not the case for all analytes nor for all lakes: one example
of this exception is shown for Lake Superior's nitrate (NO.i and
Total Nitrogen (TN) le\ els (Fig. 2).
Recognizing the considerable variability, it is still instructi\e
to look at average conditions (Figs. 3-5) across the lakes. Two
overall patterns are highlighted. One is exemplified by TP and
chlorophyll, where levels tend to appear higher on average in the
nearshore (Fig. 3): Lake Ontario is an exception in this data set'.
The iruijontv of samplini: that was conducted in Lake Ontario was in June 2(10? and earlier in the summer than most sampling (biased to August and early
September). The values for Lake Ontario appear low compared to a modest sampling we also conducted at -e\ eral -lies in 2004 and in relation to some other
summer summaries (Holeck ci al. 2008. Hccky et al. 2007). Moreover, the western nearshore end of the lake, which is nutrient rich, was not sampled as
pan of our studies On the other hand, recent studies in both Lake Ontario and Lake Erie suggest there are nearshore areas which are less distinct from the
offshore, an effect which is attributed to mussels and C'ladophora (Smith et al. 200". 1 lecky. > / al. 2007).
NEARSHORE AREAS OF THE GREAT LAKES 2009
51
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A second pattern is contrasting. NO, and silicate concentrations
(Fig. 4) are very similar between nearshore and offshore waters
in the upper lakes (Superior. Huron. Michigan); but for the two
lower lakes, the nearshore appears substantially higher in both
silicate and NO,. Interestingly. Lake Erie's and Lake Ontario's
nearshores are more enriched in NO, compared to all other
nearshore and offshore waters (Fig. 4c). Ratios between P. N.
and silicate can affect the plankton community; in this regard
there appear to be some ecologically-significant differences.
from upper to lower lakes. The contrasting patterns suggest
that, from lake to lake, there are some different relationships
between nearshore and offshore interactions and nutrient
cycling. For example. Lake Superior has some rather distinct
differences in TP and chlorophyll concentrations inshore to
offshore, but not for NO, or silicate. In contrast, there appears
a strong inshore-offshore gradient in NO,. TP. and chlorophyll
concentrations in Lake Erie. Reasons may be complex, but
some lake-to-lake and within-lake differences likely relate to
watershed use (see later section).
N
• TN
500
Nearshore i<30 m) Midshore (30-150 m) Offshore (>150 m)
DTP
nCI
i Chi a
5.00
4.00
3.00
2.00
1.00
0.00
Nearshore (<30 m) Midshore (30-150 m) Offshore (> 150 m)
Figure 2. Comparison of mean summer concentrations in
epilimnion water composites in Lake Superior.
A 52-station sampling was conducted across three depth
strata in 2006. Concentrations units are as indicated in Table
1, except for N forms, which are in ug-N/L.
Source U.S. EPA. Mid-Continent Ecology Division
Nearshore
Offshore
Nearshore
Offshore
•)\M -\\nii in at ;vi cnl nutrient
One way to assess concentrations is in relation to nutrient
loading targets provided under the Great Lakes Water Quality
Agreement (GLWQA). Conversion of loading to an equivalent
average ambient lake-wide concentration is potentially
confounded by a number of things including benthic algal
urowth. like ( 'Imiophoru. and invasiv e dreissenid mussels, each of which can temporarily remove P from water and store it in biomass.
Lake Erie's GLWQA based-loading targets have been equated to -10-15 ug L TP (Eastern vs. Western basins, respectively), when
expressed as basin-wide concentrations. Lake Michigan's average concentration at the loading target (5.600 metric tons) previously
was estimated as 7 ug L when expressed as an average concentration: the newest high-resolution mass-balance model runs suggest
the loading target would translatetoalakewideconcentrationof~7.5u.g/L(Pauer«7 al. 2008). Pendinga future revision of the GLWQA,
it is nonetheless
clear at this time that
nearshore waters are
recommended as a
primary focal point
(1JC 2006). There are
no specific criteria
for the nearshore of
different lakes, but due
to volume differences
nearshore loading
could be at least 2-4x
the lake-wide estimate
and still satisfy a
lake-wide loading
target. Using rough
"guideline" values of
75 ug L. 10 ug L. and
15 ug L TP as simple
touchstones, the data
sets explored above
reveal the following.
based on n = 501
20
18
16
14
o
Superior Huron Michigan Erie Ontario
s.
O
Superior Huron Michigan Erie Ontario
Figure 3. Comparison of nearshore and offshore data by lake for sampling during the 2001-2007
period, a) Total phosphorus; b) Chlorophyll a.
Mean summer values for each lake (see Tables 1-2).
Source: U.S. EPA. Mid-Continent Ecology Division and U.S. EPA. GLNPO
NEARSHORE AREAS OF THE GREAT LAKES 2009
52
-------
O)
.
SS
500
450
400
350
300
250
200
150
100
50
0
Nearshore -o-Offshore
Superior Huron Michigan Erie Ontario
b
-•-Nearshore -
^-Offshore
op
en
1.5
13
0>
"5
(A
tA
0.5
Superior Huron Michigan Erie Ontario
c
nr
N and Si
• Nearshore ° Offshore
This simple comparison and the others in figures presented
make it clear that the nearshore waters have, in general,
higher TP levels at local sites and on average, compared to
offshore waters, which is neither surprising nor unexpected
based on historical observations. Recent data also reinforce
the notion that Lake Erie's TP levels continue to be high.
Nutrients and chlorophyll
One of the interesting patterns between nearshore and offshore
conditions appears in the relationship between average lake
values for TP and chlorophyll (Fig. 5). Gregor and Rast (1982)
had pointed out that nearshore waters generally contained
lower chlorophyll concentrations for a given TP level than
offshore waters, during the 1960s and 1970s, well prior to
mussel invasions. Edsall and Charlton (1997), Nichols et al.
(1999) and Depew et al. (2006), among others, all confirmed
that where mussels invaded, a lowered water column
chlorophyll relative to TP resulted. Figure 5 shows that, for
the 2001-2007 period, the nearshore characteristically and
distinctly differed from the offshore with respect to a lower
chlorophyll at a given TP level. The suggested difference,
about 10% lower chlorophyll in nearshore waters, is similar
to that described for the nearshore by Gregor and Rast (1979,
1982) for pre-mussel conditions. Curiously, Lake Superior,
the only lake where nearshore and offshore has not yet
experienced a mussel invasion, is not an exception; it is worth
noting that Gregor and Rast (1979, 1982) as well as others
have recognized that chlorophyll-TP relationships may be
altered by suspended solids and light, among other factors
not involving invasive species.
The possible exception to the trend in Figure 5 is Lake
Ontario, although a caveat for Ontario data was footnoted
previously. Recent reports for Lake Ontario and eastern
Lake Erie do however suggest that, because of extended
mussel populations and associated, extensive re-growth
of Cladophora (e.g., Higgins et al. 2006, Hecky et al. 2007, Smith et al. 2007, Malkin et al. 2008), the dynamic between TP
loading and planktonic chlorophyll has been altered. The suggestion is that shunting of P through mussels and then to benthic
NEARSHORE AREAS OF THE GREAT LAKES 2009
8 1-5
55 ,
0>
> 0.5
O
(O
.<2 o
y = 0.012x- 1.98
R2 = 0.89
Offshore Trend
Ontario Erie
100
200
300
400
500
Total Nitrate + Nitrite
Figure 4. Comparison of nearshore and offshore data by lake
for sampling during the 2001-2007 period, a) Nitrate + nitrite; b)
Silicate; c) Silica vs. (Nitrate + nitrite).
Mean summer values for each lake (see Tables 1-2).
Source: U.S. EPA, Mid-Continent Ecology Division and U.S. EPA, GLNPO.
offshore stations sampled 2001-2007 and n = 535 nearshore
stations sampled 2002-2007:
> 15 ug/1 TP
> 10 ug/1 TP
> 7.5 ug/1 TP
3% of Offshore (epilimnion) samples;
only exceeded in Lake Erie
8% of Nearshore samples; mostly
Erie, but found in all lakes
7% of Offshore (epilimnion) samples;
only exceeded in Lake Erie
18% of Nearshore samples; mostly
Erie, many sites in each lake
10% of Offshore (epilimnion)
samples; only Lake Erie
36% of Nearshore samples;
occurs in all lakes
— 53
-------
• Nears hore ° Offs hore
7
/
6
IT 5
~O)
3 4
co 3
£ 9
O 2
1
0
9
X
X
Offshore x^x
y=0.418x-0.03 xx"
R2=0.98 X> ^/'
.S X
^r S
5* ,'' Nearshore
/ ,''* y=0.395x-1.07
OT "• R2=0.91
0 5 10 15 20
TP Gig/L)
Figure 5. Mean Chlorophyll a - TP relationship for nearshore
and offshore of each of the five lakes for summer during the
2001-2007 period.
Lines show linear regression models independently fit to each
depth strata. Averages are by lake.
Source: U.S. EPA, Mid-Continent Ecology Division and U.S. EPA, GLNPO.
algae is concomitant with lowering of water column TP, and
lower chlorophyll because of mussel filtering; together this
new ecology may create nearshore areas that are not very
different from more offshore waters. We do not fully know
about dynamics for all areas, which may involve time-varying
changes in loading rates, water movement/circulation, mussels,
benthic algae, and TP/chlorophyll trends; but there are
compelling illustrations at some locations where nearshore-
offshore differences in nutrients or chlorophyll are slight and/
or indistinguishable. Perhaps the most important reminder is
that use of nutrient concentrations alone, as simple assessment
criteria, is not always simple.
Trends \
Generational and decadal patterns
Nearly a scientific generation ago, Gregor and Rast (1979)
compiled nearshore data for pre-phosphorus abatement/
GLWQA periods (late 1960s to early 1970s). Although more
sparse on the U.S. side, data were available for most of the
lakes. The range was from <3 ug/L (detection limits) to >100
ug/L. The entire Lake Ontario nearshore routinely exceeded 15
ug/L, as did Lake Erie. Some locations in Lake Huron exceeded
10 ug/L or even 15 ug/L, principally in Saginaw Bay and the Midland, ON area. Areas noted in Lake Michigan with very high
values (>15 ug/L) included those off Milwaukee and east of Chicago, and much of Lake Michigan was 7-10 ug/L. \n Lake Superior,
high values (>15 ug/L) included areas in Thunder Bay and in the western arm around Duluth.
In 1996, Edsall and Charlton (1997) noted that some sites in Lake Ontario and Erie exceeded 10 ug/L or even 15 jig/L TP. Quasi-
synoptic information does not appear to be available.
The above summary for the current decade suggests exceedance of 15 ug/L occurred in the nearshore. Eighteen percent of samples
taken in the nearshore exceeded 10 ug/L and over one-third were above 7.5 u.g/L. In general, recent concentrations may be
comparable to the nearshore of the 1990s, but at a regional level, it is not really possible to make strong comparisons of the 2000s
era data with the preceding two decades, barring some additional, more comprehensive data. The issue of conducting a consistent,
comprehensive collection of nearshore data continues today.
Overall assessment
By many observers' eyes, nearshore conditions are low (if not also declining) in overall water and habitat quality, especially within
the lower lakes (cf. Mackey and Gofbrth 2005, Niemi et al. 2007). By any observer's eyes, nearshore conditions are spatially
variable and temporally highly dynamic. These ecosystems have been continuously changing in response to changes in external
loading as well as internal factors such as the mussel invasion. Open nearshore and even offshore waters are changed by mussel
invasions in all the lakes, but Superior, whose edges though have been recently invaded by the quagga mussel (Grigorovich et al.
2008).
Pressures (that directly or indirectly affect status of nutrients)
Studies have recently re-emphasized the old notion that the lakes, even as large as they are, exist in a basin. Also, coastal waters
are frontline receiving regions that are sensitive to basin-wide trends. Recent findings emphasize that there are numerous human
activities on the landscape that create pressures which can trickle down to affect nutrient concentrations and ecological responses
in coastal and open nearshore waters.
T-andscape changes
The Great Lakes terrestrial basin, at least the U.S portion, has continued to change and be developed. Wolter et al. (2006) estimated
that 2.5% of the area (798,755 hectares [1,793,767 acres]) experienced a land use/land cover change from 1992 to 2001, and this
rate exceeded that predicted by the rate of population growth. Moreover, the change is heavily biased to the near-coastal zone.
From Wolter et al. (2006): "...49.3% of the change that occurred within the watershed [the U.S. basin draining to the Great
NEARSHORE AREAS OF THE GREAT LAKES 2009
54
-------
Agriculture
0-0.2
0.2-0.4
0.4-0.6
0.6-0.8
0.8- 1
1 Nearshore Offshore
c
o
c
G
o
c
o
o
c
c
Lakes] between 1992 and 2001 imolved transitions of
non-developed land to developed land. ...This steady
increase in hardened surface area is of particular
concern for near-shore areas of the Great Lakes and
the watershed as a whole. Over 21"o (-84.000 hectares
[207.569 acres]) of all newly developed land within the
basin between 1992 and 2001 occurred within 10 km of a
shoreline, even though this only represents 0.27° o of the
whole watershed."
"igure 6 illustrates the relationship between the basin's
andscape condition and nutrient concentrations in the
akes—the scale is lakewide. both offshore and in the
aggregate frontline receiving waters of the nearshorc.
\l more local scales, the connection between landscape
:ondition metrics and the resultant downstream
concentrations in the water of coastal ecosystems has
become strongly established for coastal wetlands.
and the effect generally carries, somewhat diluted, to
embayments and the more open nearshore (cf. Danz ct al.
2007. Nicmi ct <;/. 2007. Trebit/ ct al. 200~. Kireta ct al.
2iur. Reavie 2007. Yurista and Kelly 2007). Morrice ct
al. (2007) demonstrated that the coastal wetland nutrient
concentrations (TN. TP) and chlorophyll arc influenced
by an aggregate of human activ ities. i.e.. not just from
agriculture (e.g.. Fig. ft), hut including land use change.
the density of human populations, point sources, and other
atmospheric and terrestrial features modified by humans.
The broad scale or site-specific effects of changes in
nearshore water quality from landscape changes on the
order of 2.5% of the entire watershed may not be eas>
to predict. Significant effects on coastal waters may be
more keyed to some types of landscape changes than
others, and sensitive to the spatial mosaic of land use
throughout the watershed. Continuing research efforts
will help define these connections and perhaps offer
some managed growth alternative. Nonetheless, the
recent direction of landscape change would indicate
the prospect of increased loading to coastal waters, and
this should be expected from the aggregate increase in
various human acti\ ities.
Management Implications
The nature and strength of landscape influences on
nearshore lake processes are being quantitatively
described. At the same time we can project that human populations and activities in the Great Lakes coastal zones will continue
to rise. These two intersecting trends should provide both impetus and means to relate watershed-based pressure and nearshore
state, and therefore to formulate general land management plans. It will take more effort to bring pressure-state projections to
local and small watershed levels, as these scales demand more detailed spatial modeling. The will to establish land use. zoning and
land management practices will likely become a pressing management topic. This is a complex issue interwoven with societal and
economic drivers, not just environmental pressures and ecological responses.
20
18
.
'•.
10
-
-
-5-4-3-2-1012345
Agriculture PC1
(Weighted average for segmentsheds in each lake)
Figure 6. Agriculture landscape metric and TP concentrations
across the Great Lakes.
a) The distribution of an agriculture Principal Component (PC1) from
Danz et al. (2005, 2007).
The summary metric is based on CIS data (circa 1990s to 2000)
for 21 agricultural-chemical variables on 762 segmentsheds
(Hollenhorst et al. 2007) across the entire U.S. basin.
b) Trends in summer TP (ug/L), as related to the agriculture PC1.
Calculated for entire U.S. basin draining to each given lake.
Concentrations are the simple arithmetic mean for all data within the
2001-2007 period (Tables 1 and 2).
Sources: a) Danz et al. (2005. 2007) and Hollenhorst et al. (2007); b) Danz et al. (2005).
NEARSHORE AREAS OF THE GREAT LAKES 2009
55
-------
Comments from the Author
On the need for consistent monitoring
There is broad recognition that the nearshore has not been regularly or comprehensively sampled (e.g Mackey and Goforth 2004,
IJC 2006, SOLEC 1996, this chapter). Recent studies demonstrate that the variability in the nearshore can be overcome with
adequate sampling, which in the past has hindered the attempt. Development of explicit nearshore nutrient criteria or benchmarks
might be considered; future monitoring/assessments would be strengthened and could be indexed against such benchmarks.
There are also recent approaches that have successfully incorporated nearshore and offshore sampling into unified whole lake
assessments. We should strive to do so, on a more regular basis.
An upcoming effort led by the U.S. EPA's Office of Water is the National Coastal Survey, to be conducted with coastal States'
participation. The survey, planned for 2010, will be the first in the U.S. to report on the Great Lakes coastal condition through
a thorough sampling of the nearshore at about 250 sites. The data will provide an opportunity to make both regional-scale
assessments and assessments for each of the lakes on a repeating cycle (every five years). Although it presently is planned only for
the U.S. shoreline, this is the kind of program necessary to^urvey the nearshore on a consistent and unbiased basis, and it may be
a continuing platform to work towards an integration of monitoring from the basin to the offshore.
On technology and trends in our ability to examine landscape-nearshore linkages
It is interesting to compare images of Gregor and Rast (1979) with images that can be generated today (Fig. 7). Gregor and Rast
(1979,1982) classified nearshore waters and felt that variations in trophic status "compared favorably" with geographic land areas
and shorelines described by their relative potential for nutrient export based on soil, land use, and hydrologic characteristics
(described by Johnson et al. 1978). Gregor and Rast (1979, 1982) viewed the direct cause-effect relationship between land use and
nearshore trophic status as a qualitative, but obvious, finding for the data of the early 1970s.
The generational advances of remote sensing and an ability to compile extensive spatial data in GIS layers allow characterization
of the entire Great Lakes basin (Fig. 7). There is now a framework to study the influence of landscape-derived pressures on
the nearshore; there are many scales (Hollenhorst et al. 2007) still to be explored. Recent advances in nearshore sampling
strategies show that continuous sensing with towed in situ sensors is feasible and can provide spatially-explicit water quality
information across vast nearshore regions. Nearshore variability can be sampled as a virtual census of the entire water column
(both horizontally and vertically) with a variety of sensors, and the suite of available sensors continues to expand. Results have
indicated strong, quantifiable links between water quality and biology in the nearshore and indicators of landscape condition in
the adjacent watersheds (Fig. 8). In conclusion, the future of nearshore assessment is bright; the technological means to quantify
linkages and better fulfill the vision of Gregor and Rast (1979,1982) is available. Time will tell how successful we can be in putting
these technologies into practice on a sustained basis to aid management decisions.
Acknowledgements
Author: John R. Kelly, U.S. EPA, Office of Research and Development, National Health and Environmental Effects Research
Laboratory, Mid-Continent Ecology Division, Duluth, MN 55804
Anne Cotter at the Mid-Continent Ecology (MED) Division of EPA coordinated the nearshore nutrient analyses in our program
over the past 6 years.
A host of MED scientists have played significant roles in this program, including: Peder Yurista, Anne Cotter, Sam Miller, John
Morrice, Greg Peterson, Jill Scharold, Mike Sierszen, Mike Knuth, Anett Trebitz, Tim Corry, Corlis West, Leroy Anderson,
Joel Hoffman, and Mario Picinich.
Thanks to David Rockwell and Glenn Warren of the U.S EPA Great Lakes National Program Office for providing offshore
monitoring data for comparisons presented here. Ed Mills and Kristin Holeck at Cornell graciously provided data, reports,
and insights on recent Lake Ontario trends, including recent LOLA studies. Bob Hecky (now at Large Lakes Observatory,
University of Minnesota Duluth) graciously shared insights and reports on eastern Lake Erie and western Lake Ontario. Thanks
also to Jan Ciborowski (U. Windsor) and Russ Kreis (U.S. EPA-MED, Grosse-Ile) for information and many discussions on
lake trends and for sharing historical insights on Lake Erie and Michigan in particular, and to Jerry Niemi (University of
Minnesota Duluth) and a cast of many on the GLEI project whose efforts have helped enable my impressions regarding the
influence of coastal landscapes upon nearshore waters.
NEARSHORE AREAS OF THE GREAT LAKES 2009
— 56 —
-------
TROPHIC STATUS
(based on total phosphorus.
chlorophyll a and Secchi depth)
OLIGOTROPHIC
OLIGOTROPHIC / MESOTROPHIC
EUTROPHIC
MESOTROPHIC / EUTROPHIC
MESOTROPHIC
INSUFFICIENT DATAAVAILABLE
AREAS WHERE SOIL. LAND USE.
, AND HYDROLOGIC CONDITIONS
.PRODUCE THE SEDIMENT AND
PHOSPHORUS LOADS TO THE
GREAT LAKES
.AREAS WITH THE POTENTIAL TO
JPRODUCE LARGE SEDIMENT AND
PHOSPHORUS LOADS TO THE
GREAT LAKES
Note: Nearshore zones not
drawn to scale.
Stress Index
Bo.o - 0.2
0.2-0.4
0.4 - 0.6
• 0.6 - 0.8
• 0.8- 1.0
Figure 7. Perspectives on landscape and nearshore condition from the 1970s and the early 2000s.
a) Summary figure from Gregor and Rast (1979) to illustrate nearshore areas of different trophic status and potential
relationship to landscape characteristics.
b) Summary figure from Niemi et al. (2007).
Response-based cumulative landscape stress index. Derived from landscape attributes circa 20!
the U.S. shoreline and calibrated to biological response in receiving coastal systems.
Sources: a) Gregor and Rast (1979): b) Nlemi el a/. (2007).
NEARSHORE AREAS OF THE GREAT LAKES 2009
57
-------
:•
,
Apostle Island
:
Figure 8. A shoreline nearshore transect over 537 km track in western Lake Superior surveyed with continuous in situ sensors
oscillated throughout the water column (Modified from Yurista and Kelly, 2007).
Upper panel shows track with adjacent watersheds, where watershed colors are scaled to show different agriculture PC1
values (as in Figure 8). Lower panel shows in situ fluorescence, calibrated relative to chlorophyll a. along the entire track.
Values are high near Duluth and along the south shore to the Apostle Islands, in association with higher agricultural PC1
scores. Yurista and Kelly (2007) provide multivariate regression models that relate water quality along the track to adjacent
shoreline landscape metrics.
Source: Modified from Yurista and Kelly (2007).
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Res. 32:607-628.
Yurista, P.M., Kelly, J.R., and Miller, S. 2005. Evaluation of optically acquired zooplankton size-spectrum data as a potential tool
for assessment of condition in the Great Lakes. Environ. Manage. 35(l):34-44.
Yurista, P.M., Kelly, J.R., and Miller, S. 2006. Comparisons of zooplankton community size structure in the Great Lakes. J.
Geophys. Res. Ill, C05S08, doi: 10.1029/2005JC002971.
Yurista, P.M., and Kelly, J.R. 2007. Spatial patterns of water quality and plankton from high-resolution continuous in situ sensing
along a 537-km nearshore transect of western Lake Superior, 2004. Special Lake Superior Issue, Aquatic Ecosystem Health
and Management Journal, Ecovision World Monograph Series. Backhuys Publishers, the Netherlands.
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5.2 Nonindigenous Species (NIS)
State of the Ecosystem
Nearshore and coastal waters provide habitat tor all 1S4
nonindigenous species (NIS) introduced to the Great Lakes
since 1840; none are restricted exclusively to offshore
areas. These habitats have been profoundly altered by
NIS. with effects ranging from uprooting of wetland
plants by common carp to direct and indirect creation of
microhabttats by dreissenid mussels. The status of Great
Lakes nearshore waters with respect to NIS is poor. Since
1996, IS new NIS (Table I) have been discovered - a rate
of 1.5/year. This rate is higher than the long-term discovery
rate (I.I/year since 1840). but lower than the rate since the
opening of the St. Lawrence Seaway in 1959 (1.8/year)
(Fig. 1). Despite the slightly lower discovery rate in the
last decade, any increase in the number of NIS in the Great
Lakes represents a deteriorating trend since additional
NIS may portend further disruption of existing food webs,
in many cases in unpredictable and or undesirable ways.
1830 1850 1870 1890 1910 1930 1950 1970 1990 20
Year
Figure 1. Cumulative number of aquatic NIS discovered in the
Great Lakes basin since 1840.
Sources: Mills etal. (1993); Ricciardi (2001); Grigorovich et al. (2003); Ricciardi
(2006).
Of the IS NIS introduced since 1996. 12 are attributed to the ship vector and nine are native to Eurasia-proportions consistent
with historical patterns (Kelly ct al. in press). Lake Michigan and Lake Ontario were lirsl discovery sites for seven and six
species, respectively; Lake Erie, Lake St. Clair and connecting waters hosted four; and Lake Superior harbored one -Gammarus
Year
1996
1997
1998
1998
1999
1999
2000
2001
2001
2001
2002
2002
2002
2002
2002
2003
2005
2006
NIS
Heteropsyllus nr. nunni
Acineta nitocrae
Cercopagis pengoi
Schizopera borutzkyi
Daphnia lumholtzi
Nitokra incerta
Heterospohs sp.
Gammarus tigrinus
Psammonobiotus communis
Rhabdovirus carpio
Cylindrospermopsis raciborskii
Piscirickettsia cf. sa/monis
Psammonobiotus lineahs
Psammonobiotus sp.
Ranavirus sp.
Enteromorpha flexuosa
Novirhabdovirus sp.
Hemimysis anomala
Common Name
harpacticoid copepod
suctorian
fish-hook waterflea
harpacticoid copepod
waterflea
harpacticoid copepod
microsporidian
amphipod
testate amoeba
SVC spring viraemia of carp
cyanobacterium
muskie pox
testate amoeba
testate amoeba
largemouth bass virus
(LMBV)
green alga
Viral Hemorrhagic
Septicemia (VMS) virus
mysid shrimp
Region of
Origin
Atlantic North
America
Eurasia
Ponto-Caspian
Ponto-Caspian
Africa
Ponto-Caspian
Unknown
Atlantic NA
Ponto-Caspian
Eurasia
South America
Unknown
Ponto-Caspian
Ponto-Caspian
Unknown
Widespread
Atlantic North
America
Ponto-Caspian
Lake of First
Discovery
Lake Michigan
Lake Erie
Lake Ontario
Lake Michigan
Lake Erie
Detroit River
Lake Ontario
Lake Superior
Lake Ontario
Lake Michigan
Lake Michigan
Lake St. Clair
Lake Ontario
Lake Ontario
Lake Michigan
Lake Michigan
Lake Ontario
Lake Michigan
Vector
Shipping
Shipping
Shipping
Shipping
Unintentional release
Shipping
Unknown
Shipping
Shipping
Unknown
Unknown
Unknown
Shipping
Shipping
Unintentional release
Shipping
Shipping
Shipping
Table 1. NIS discovered in the Great Lakes since 1996
Sources: Ricciardi (2001): Grigorovich et al. (2003): Ricciardi (2006); Great Lakes Aquatic Nonindigenous Species Information System (GLANSIS)
(http://www.glerl.noaa.gov/res/Programs/ncrais/glansis.html).
NEARSHORE AREAS OF THE GREAT LAKES 2009
61
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• Fauna
• Flora
Total=184
Unknown Ontario Erie Michigan Huron Superior
Lake/Basin of first discovery
Figure 2. Location of first discovery for NIS in the Great Lakes
since 1840.
Discoveries in connecting waters between Lakes Huron, Erie.
and Ontario were assigned to the downstream lake. Species
that were widespread at the time of discovery were assigned to
the unknown category.
Source: Great Lakes Aquatic Nomndigenous Species Information System
. wwglerl noaa gov/res'Programs/ncrais/glansis html).
rigrinu* (amphipod)—which was also found in Lake Huron
one year later. This distribution is generally consistent
with historical patterns (Fig. 2). although discoveries
have become more prevalent in Lake Michigan in recent
years. Species discovered since 1996 that have the greatest
potential to disrupt Great Lakes nearshore ecosystems are
Cercopagis pcngoi (fishhook waterflea) (discovered 1998).
viral hemorrhagic septicemia (VMS) (discovered 2005). and
Hemimysis anomala (bloody-red shrimp) (discovered 2006).
Cercopagis. present in Lakes Ontario. Erie, and Michigan.
preys on zooplankton. impacts native zooplankton species
community composition, and competes with planktivorous
fish for food. VHS. a virus originally believed to affect only
salmonid species, is responsible for die-offs of muskellunge.
smallmouth bass, northern pike, freshwater drum, gizzard
shad, yellow perch, round goby, lake whitefish. Chinook
salmon, and walleye in all the Great Lakes except Lake
Superior. Hemimysis. a mysid shrimp that has become
established in Lakes Ontario. Michigan, and Erie. was
predicted to invade the Great Lakes because of its likelihood
of surviving transport in ship ballast water and its extensive
recent invasion history in Europe (Ricciardi and Rasmussen
Il'l)S). Hcmiinysis is a shallow water mysid that resides at depths from 0.5 to 50 m (generally 6 to 10 ml (Salemaa and Hietalahti
ll'l'3l. whereas the Great Lakes name A/> w\ rclicta (opossum shrimp) prefers deeper waters. Hcniini\:\i.\ has the potential to be
both a food competitor with young fish and a food source for older fish.
No new tish species have been discovered Mnce 1996. but several fish diseases are cause for concern. VHS. spring viremia of carp
(SVC), and largemouth bass virus (LMBV) have each caused die-offs offish in recent years. The VHS virus affects many (> 40)
fish species and appears to have significant potential for further spread in and around the Great Lakes Concern about the transfer
of VHS to other waters led to regulation of the haittish industry in all U.S. Great Lakes states: haitfish that are to be transported to
waters other than those in which they were collected must be certified disease free. SVC has caused large die-offs of ornamental
koi in aquaculture facilities in Virginia and North Carolina. Carrier carp have been isolated from the Calumet-Sag Channel (Lake
Michigan basin) that connects Lake Michigan to the Mississippi drainage and from Hamilton Harbor. Lake Ontario. LMBV has
been detected in fish in Lake St. Clair and the Bay of Quinte. Lake Ontario although no large fish kills have been reported to date
in the Great Lakes basin. Large kills have occurred in several southern states and appear to be related to thermally-stressed fish. In
addition to viruses, five protozoa and one bacterium have been discovered since 1996. This shift in the pattern of discovery toward
microscopic organisms likely reflects greater research efforts to identify new NIS.
Pressures
Ballast water discharge
New regulations in Canada (2006) and in the United States (2008) require transoceanic ships declaring no ballast on board to flush
their ballast tanks with saline water, but the method does not provide 100".i efficacy. While planktonic organisms will be flushed
or killed with close to 100°o efficiency (Gray ct til. 2007), species with resistant life stages may still gain entry. Also. NIS may
still be transferred within the Great Lakes by "lakers" vessels that do not leave the Great Lakes-St. Lawrence Seaway system.
but do transfer ballast water between Great Lakes ports (Rup 2008). New ballast water treatment technologies (heat. L'V light.
chemicals, and filtration) show promise for both oceangoing and lake vessels, particularly when used in combination, although
their application to Great Lakes conditions needs further attention.
Other vectors
MS may continue to be introduced and spread by other vectors. Baitfish may contain more than one species, including NIS like
round gobio (\t'i>^nhins mclnnostomtts). In addition, infected baitfish could vector VHS to inland lakes. Asian carp species
(bighead. silver) from the Mississippi drainage still threaten to enter Lake Michigan through the Chicago Sanitary and Ship Canal.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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despite the presence of an electric barrier. Growth in aquaculture, live gardens, and the aquarium trade increase the risk that NIS
will be introduced either intentionally or unintentionally (Cohen et al. 2007).
Synergistic effects
Combined effects of water quality change, climate change, and facilitative interactions between NIS may increase the pressures
exerted on nearshore waters of the Great Lakes. NIS may act in concert with one another with results that are more severe than the
effect of any NIS alone (Ricciardi 2001,2005). For example, recurring outbreaks of avian botulism resulting in the deaths of large
numbers of waterfowl in Lakes Erie and Ontario are thought to result from the combined effects of dreissenid mussels and round
gobies. It has been suggested that mussels, through deposition of pseudofeces, create environmental conditions that promote the
pathogenic bacterium, and round gobies, through their ingestion of mussels, transfer bacterial toxin from the mussels to higher
levels of the food web (Yule et al. 2006). Warming temperatures and changing water quality (e.g. increasing clarity, declining
nutrients) may enhance the success of established NIS that have a broader range of environmental tolerance as compared with
native species.
Range expansions of established NIS
Although there have been no new vascular plant discoveries in the Great Lakes since 1996, several established invasive plant
species continue to spread. Since 1996, new records of purple loosestrife (Lythrum salicaria) have been documented in all Great
Lakes states except Indiana and Illinois (USGS 2008). Purple loosestrife replaces cattail and other native wetland plants resulting
in the alteration of the structure and function of wetlands. Large infestations reduce native foods and cover for wildlife and can
impede water flow. Phragmites australis, or common reed, is also spreading throughout the Great Lakes basin. Recent research
demonstrates the presence of two genotypes—one native and one invasive. It is the invasive European genotype that has expanded
its range in the Great Lakes basin in areas such as Lake St. Clair; Long Point, Lake Erie; and Green Bay, Lake Michigan.
Phragmites forms dense monospecific stands, altering native wetland plant and wildlife communities. Additional macrophytes
including Hydrilla verticillata and Cabomba caroliniana (Carolina fanwort) are currently found in water adjacent to the Great
Lakes, and could pose significant problems in shallow wetland areas if introduced.
Dreissenid mussels have continued to expand their range, with quagga mussels (Dreissena bugensis) replacing zebra mussels
(Dreissena polymorphd) in numerous nearshore and offshore habitats in Lakes Erie, Michigan, and Ontario. Dreissenid mussels
may be partially responsible for lack of improvement in nearshore water quality despite distinct improvements in offshore waters
due to declines in phosphorus loadings. Hecky et al. (2004) suggest that dreissenids sequester phosphorus in nearshore areas
through their filtering activity and through deposition of pseudofeces (nearshore shunt hypothesis).
Management Implications
The introduction of each new NIS adds ever-increasing complexity to Great Lakes food webs. Before the effects of any one
invader are known, another arrives, confounding research results and forcing modification of previously successful management
strategies in the face of uncertainty. Prevention of new introductions will require aggressive vector management (e.g. ballast water
exchange, to be replaced by ballast water treatment, for all vessels) coupled with continued monitoring to determine the efficacy
of preventative measures. New ballast water regulations for transoceanic No Ballast Onboard (NOBOB) vessels should reduce the
risk of introduction of new NIS in Great Lakes waters, but interlake transfer of ballast water by vessels that do not leave the Great
Lakes will continue to spread existing NIS among the lakes. Transfer of unexchanged ballast water to the Great Lakes by vessels
originating from coastal ports of North America must also be explored. Some species, including the amphipod Gammarus tigrinus,
may have entered the lakes via ballast discharge from a coastal vessel. Nearshore and coastal habitats in the Great Lakes continue
to be significantly impacted by NIS and are areas that require increased attention by scientists, managers, and policymakers.
Comments from the authors
To better assess nearshore and coastal waters, facilitative and/or synergistic effects should be assessed. Data access is typically
quite good; NOAA's Great Lakes Aquatic Nonindigenous Species Information System (GLANSIS) provides reliable information.
Endpoints that would infer achievement of good quality nearshore waters are no new NIS discoveries, a decrease in the discovery
rate, and confinement of existing NIS to current distributions (no spread). It must be acknowledged, however, that time lags
between introduction and discovery of NIS could result in further finds of NIS in the Great Lakes even after the vectors responsible
for their introduction have been muted or eliminated.
Acknowledgments
Authors:
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Kristen T. Holeck, Department of Natural Resources, Cornell University, Cornell Biological Field Station, Bridgeport, NY
Edward L. Mills, Department of Natural Resources, Cornell University, Cornell Biological Field Station, Bridgeport, NY
Hugh Maclsaac, Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada
Anthony Ricciardi, Redpath Museum, McGill University, Montreal, QC, Canada
Information Sources
Cohen, J., Mirotchnick, N., and Leung, B. 2007. Thousands introduced annually: the aquarium pathway and non-indigenous plants
in the St. Lawrence Seaway. Frontiers in Ecology and the Environment 5:528-532.
Gray, D.K., Johengen, T., Reid, D.F., and Maclsaac, H.J. 2007. Efficacy of open-ocean ballast water exchange as a means of
preventing invertebrate invasions between freshwater ports. Limnol. Oceanogr. 52:2386-2397.
Grigorovich, I.A., Colautti, R.I., Mills, E.L., Holeck, K.T., Ballert, A.G., and Maclsaac, H.J. 2003. Ballast-mediated animal
introductions in the Laurentian Great Lakes: retrospective and prospective analyses. Can. J. Fish. Aquat. Sci. 60:740-756.
Hecky, R. E., Smith, R.E.H., Barton, D.R., Guildford, S.J., Taylor, W.D., Charlton, M.N., and Howell, T. 2004. The nearshore
phosphorus shunt: a consequence of ecosystem engineering by dreissenids in the Laurentian Great Lakes. Can. J. Fish. Aquat.
Sci. 61: 1285-1293.
Kelly, D.W., Lamberti, G., and Maclsaac, H.J. In press. Laurentian Great Lakes as a case study of biological invasion. In: ISIS
Bioeconomics of Biological Invasions, eds. R. Keller, M. Lewis, and D. Lodge.
Mills, E.L., Leach, J.H., Carlton, J.T., and Secor, C.L. 1993. Exotic species in the Great Lakes: A history of biotic crises and
anthropogenic introductions. J. Great Lakes Res. 19(l):l-54.
Ricciardi, A. 2001. Facilitative interactions among aquatic invaders: is an "invasional meltdown" occurring in the Great Lakes?
Can. J. Fish. Aquat. Sci. 58:2513-2525.
Ricciardi, A. 2005. Facilitation and synergistic interactions among introduced aquatic species. In: Invasive Alien Species: A New
Synthesis, eds, H.A. Mooney, R.N. Mack, J. McNeely, L.E. Neville, P.J. Schei, and J.K. Waage. Pp. 162-178. Washington, DC:
Island Press.
Ricciardi, A. 2006. Patterns of invasions in the Laurentian Great Lakes in relation to changes in vector activity. Diversity and
Distributions 12:425-433.
Ricciardi, A., and Rasmussen, J.B. 1998. Predicting the identity and impact of future biological invaders: a priority for aquatic
resource management. Can. J. Fish. Aquat. Sci. 55:1759-1765.
Rup, M. 2008. Examination of ballast water movement by domestic vessels in the Great Lakes as vector of introduction or spread
of aquatic nonindigenous speices. BSc thesis, University of Windsor. 25p.
Salemaa, H. and Hietalahti, V. 1993. Hemimysis anomala G. O. Sars (Crustacea: Mysidacea) - immigration of a Pontocaspian
mysid into the Baltic Sea. Annales Zoologici Fennici 30(4): 271-276.
USGS. 2008. Nonindigenous Aquatic Species Database, Gainesville, FL. http://nas.er.usgs.gov
Yule, A.M., Austin, J.W., Barker, I.K., Cadieux, B., and Moccia, R.D. 2006. Persistence of Clostridium botulinum neurotoxin Type
E in tissues from selected freshwater fish species: implications to public health. J. FoodProt. 69: 1164-1167.
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5.3 Viral Hemorrhagic Septicemia in the Great Lakes
State of the Ecosystem
Background
Viral hemorrhagic septicemia virus (VHSv) is a fish pathogen reportablc to the World Organization for Animal Health (O1E). First
reported as a disease of European rainbow trout (Oncorhym-lnis mykiss) in 193X. it was not until 1963 that a virus (VHSv) was
identified as the pathogen responsible. Since that time, three (3) VHSv genotypes have been isolated from fish in Europe, and in
1988, a fourth genotype was isolated from marine fishes in the Pacific Northwest (Meyers and Winton 1995). One of the European
genotypes significantly affects freshwater salmonids and pike, whereas the remaining two affect marine fishes (Jim Winton,
personal communication). Ciagne ct til. (2007) reported the isolation of VHSv genotype IV from brown trout (Salmo tnitta),
mummichog (FiinJiilns hctcrocliiux). striped bass (\furonc MUtiiilis), and three-spined stickleback (Gastcmstenx aculeatiis) from
New Brunswick and Nova Scotia. Canada. Genotype IV was detected in the Great Lakes in 2003 and 2005 although it is unknown
how VHSv was introduced into the Great Lakes basin. The Great Lakes strain of VHSv is most similar to the Atlantic strain of the
virus isolated by Gagne et al. (2007) and suspected vectors for the introduction and spread within the Great Lakes include ballast
water, movement of live fish (possibly baitfish) into the Great Lakes, and the natural migration offish. The strain of VHSv found
in the Great Lakes is known as VHSv-IVb. Signs of disease in fish infected with VHSv include pale gills and organs, bloated
abdomens, bulging eyes, darker body color and hemorrhaging (bleeding) on the body and in the organs. Bleeding is the most
commonly reported sign of disease.
2005 Reports
During the spring of 2005. a large mortality event affecting freshwater drum (Aplodinotiis grunniens) occurred in the Bay of
Quinte. Lake Ontario and VHSv was isolated from the diseased tish (Lumsden ci al. 2007). Although this was the first report of
VHSv in the Great Lakes, it was not the first isolation of the virus from the Great Lakes. Biologists at Michigan State University
had isolated an unknown virus from a muskellunge (Lsox nui.'it/iiiiion^y) caught in Lake St. Clair in the spring of 2003, but did not
pursue identification of the virus until learning of the Lake Ontario isolation. Confirmation of the Lake St. Clair isolation as VHSv
was made in December 2005 (Elsayed ct al. 2006).
2006 Reports
In 2006. VHSv was determined to be a causative factor in mortality events in Lake Erie, Lake Ontario, Lake St. Clair, St.
Lawrence River, and Conesus Lake (NY). The detection of VHSv in walleye (Stizosu-tlion vilreiim) from Conesus Lake was the
first inland detection of the virus in the Great Lakes basin. Within the first year after detecting VHSv. fifteen warm and cool
water species were known to be susceptible to the virus in the Great Lakes including freshwater drum, gizzard shad (Dorosoma
ce/H'tJiunHiH). muskellunge, round goby (Aw-jo/ims nicltiiioxioniiis), walleye, and yellow perch (Percaflavescens). Other Great
Lakes fish species that were shown to be carriers (no large fish kills reported) of VHSv-IVb in 2006 included bluegill (Lepomis
macrofhinis). bluntnose minnow (Pimcpha/cs nottttns). emerald shiner (Notmpis atherinoides), redhorse sucker (Moxostoma sp.)
and smallmouth bass (Micropterus dolotnieui).
In a press release dated January 25. 2007. the Michigan Department of Natural Resources (MI DNR) reported that VHSv had
been isolated from chinook salmon (O. tshuwyucliii), lake whitefish (Con^onus clii/mi/tinHis), and walleye from the Thunder Bay
(Alpena, MI) and Rogers City. Ml. regions of northern Lake Huron during the fall of 2006. Although mortality was not associated
with this report, the fish did show clinical signs of VHSv. Additionally, the MI DNR reported detecting VHSv in an archived lake
whitefish sample originally collected in the fall of 2005 near Chcboygan. Ml. by the Chippewa Ottawa Resource Agency (CORA),
a tribal organization located in the upper peninsula of Michigan.
2007 Reports
Freshwater drum kills were observed in Little Lake Butte cles Morts and Lake Winnehago in the spring of 2007, the first reports
of VHSv in Wisconsin waters (WT DNR News Release May IS. 2007). Both lakes are part of the Lake Winnebago system and are
in the Great Lakes Basin. Additional detections of VHSv were made in smallmouth bass, lake whitefish. and brown trout collected
from Wisconsin waters of Green Bay and Lake Michigan near the Door County Peninsula (W] DNR News Release May 24, 2007).
A significant fish kill occurred on Budd Lake in Clare County Michigan in the spring of 2007. Fish species affected included black
crappie (Pomoxis nigroniiicnlaitis). bluegill. largemouth bass (A/, sctlmoulcs). muskellunge. pumpkinseed sunfish (L. gibbosus),
and yellow perch (Ml DNR press release May 17. 2007). Budd Lake is land-locked, with virtually no flow in or out. suggesting
that the source of VHSv to the lake was probably a live-fish introduction such as baitfish (Gary Whelan. personal communication).
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The state of New York was the site of numerous fish kills in 2007 that were associated with VHSv. In May, a significant kill of
smallmouth bass and rock bass (Ambloplites rupestris) occurred at Skaneateles Lake in New York's Finger Lakes region (NY DEC
press release June 19,2007). A lake trout collected from Skaneateles Lake also tested positive for VHSv. VHSv was also detected
in rainbow trout collected from the Little Salmon River, sunfish collected from the Seneca-Cayuga Canal, and sunfish and koi carp
(Cyprinus carpio) collected from a farm pond in Ransomville. The farm pond was infected when the owner transferred infected
fish from nearby Twelve Mile Creek as part of a fish rescue operation (NY DEC press release July 23, 2007).
The only reported fish kill in Ontario associated with VHSv took place in Hamilton Harbour, Lake Ontario in May. There were low
numbers of dying fish of several species reported, and the virus was isolated from two diseased freshwater drum (John Lumsden,
personal communication).
By the end of 2007, the list offish species susceptible to VHSv had been expanded to include 25, with some species known to be
more susceptible to disease and dying than others. In the Great Lakes, these species included game and commercial food fish,
baitfish, predators and preyfish, and native and invasive species. This list has since been expanded to include more than 28 fish
species. Mortalities have not occurred in all species listed as susceptible. Most Great Lake jurisdictions had also implemented
monitoring programs to test fish from a variety of locations within the Great Lakes basin by the end of 2007. Several detections of
VHSv were made in these monitoring programs.
2008 Reports
The Wisconsin DNR reported a round goby kill in Lake Michigan waters just south of Milwaukee in May of 2008 (WIDNR press
release June 5,2008). Yellow perch collected nearby as part of surveillance efforts by the DNR also tested positive (WI DNR press
release June 13,2008). Similarly, rock bass and round goby collected from Illinois waters of Lake Michigan near Waukegan tested
positive for VHSv, but did not show clinical signs of the disease (IL DNR press release July 2,2008).
Sea lamprey (Petromyzon marinus) collected from northern Lake Huron tributary streams tested positive for VHSv. The animals
were collected from the Cheboygan River, Green Creek, and Ocqueoc River during routine sea lamprey trapping operations in
early June and screened for VHSv by the La Crosse Fish Health Center (LFHC) as part of the National Wild Fish Health Survey.
Clinical disease signs were not observed in the lamprey screened. The results suggest that sea lamprey may serve as a vector for
spread of the virus throughout the Great Lakes basin.
The first detection of VHSv outside of the Great Lakes basin was made from muskellunge collected from Clear Fork Reservoir
(OH) in April 2008. Clear Fork Reservoir is located in north central Ohio and drains to the Ohio River. Ovarian fluid samples
taken as part of routine fish health screening of spawning fish by the Ohio Division of Wildlife tested positive for VHSv-IVb at the
LFHC, the first isolation using ovarian fluids. Clinical disease signs were not observed in the muskellunge.
Pressures
Biological Impacts
The virus has been detected in the St. Lawrence River muskellunge population and unusually high mortalities have occurred in
this population since 2005. Casselman et al. (2008) reported that most of the muskellunge carcasses from the St. Lawrence River
were larger, mature fish likely in the age-classes of peak fecundity. Analysis of creel census data from pre- and post-mortality
years (2003-2007) indicated a 49% reduction in catch of mature individuals (Casselman et al. 2008).
Population-level effects due to VHSv-linked fish kills have not been reported at other sites in the Great Lakes basin. The Bay of
Quinte in Lake Ontario was the site of a large freshwater drum kill in 2005, the first kill associated with VHSv in the Great Lakes.
Assessments of the Bay of Quinte freshwater drum population by the Ontario Ministry of Natural Resources have not shown a
decline (Christie et al. 2008). Ontario and Michigan combined assessment data indicate that VHSv-linked fish kills in 2003 and
2006 did not have a significant impact on the adult muskellunge population in Lake St. Clair (Yunker et al. 2008). Kayle and
Wright (2008) reported that the yellow perch population in Lake Erie does not appear to have been affected by the VHSv-related
kills that occurred in the Central Basin in 2006.
It appears that fish populations already under stress from other pressures are most vulnerable to population-level impacts resulting
from fish kills associated with VHSv. Large populations that have good representation at all year-classes and strong food webs
appear to be more resilient to VHSv-related mortalities, however this will not be known with certainty for several more years until
one generation has cycled through the populations.
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Regulatory Impacts
As a response to the significant scale of the VHSv outbreaks in the Great Lakes during the spring and summer of 2006, the USDA
Animal and Plant Health Inspection Service (APHIS) issued a Federal Order on October 24,2006. The initial order prohibited the
interstate movement of VHSv-susceptible species from Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania,
and Wisconsin, as well as the importation of the same species from the Canadian provinces of Ontario and Quebec. Upon gathering
additional information, APHIS amended the Federal Order on November 14, 2006, to allow for interstate movement from the
affected states under certain conditions if the fish were for human consumption or if the fish tested negative for VHSv according
to specified standards. Additional amendments have been made to the list of susceptible species and to allow for catch and release
fishing. APHIS' interim rule for VHSv was published in the Federal Register on September 9, 2008 however, the effective date
for this rule has been delayed indefinitely (Federal Register 2009) to provide APHIS with additional time to make adjustments to
ensure the rule will be successfully implemented.
The states of Illinois, Indiana, Michigan, New York, Ohio, Pennsylvania, and Wisconsin have also adopted VHSv rules. Rules
vary by state, but generally place limits on live fish (including baitfish) movements and require testing for VHSv prior to intra- or
interstate transfer or release. The state of New York has adapted rules requiring testing for eight additional fish pathogens for
intrastate movements or importations into the state.
The Canadian Food Inspection Agency, the federal agency responsible for fish disease control and investigation, has not placed
any restrictions on the movement of fish species susceptible to VHSv. Quebec has taken steps toward the development and
implementation offish movement restrictions to help protect against the spread of VHSv. In Ontario, the OMNR first took action in
January 2007 to slow the spread of VHSv out of the Great Lakes. Recent actions include the establishment of a VHS Management
Zone that includes VHSv positive waters in Ontario. Restrictions have been placed on where baitfish may be transported, where
eggs are collected and where fish can be stocked.
Management Implications
The scale of the VHSv outbreak in 2006, the subsequent Federal Order, and state/provincial regulations have had significant
impacts on the operations of Federal, State, Provincial and Tribal natural resource agencies, as well fish-related industries and the
private sector. For resource agencies, the most significant impact has been, and will continue to be, the impact of new restrictions on
the movement of warm and cool water fishes. Most jurisdictions developed new restrictions, implemented the changes and worked
with stakeholder groups to advise and educate them on the changes. Monitoring programs were developed and implemented
and new practices were adopted for warm and cool water rearing programs which are a major component of Great Lakes basin
hatchery programs. Historically, fish health inspections have not been performed on warm and cool water fish species. Often these
species are not at the culturing facility long enough for inspection laboratory tests to be completed prior to stocking, or are reared
using extensive culture methods, which require additional effort to sample. In these instances, brood stock (which is often from
wild stocks) may need additional testing prior to egg take to ensure that the virus is not passed down from parents to progeny, or
young fish may need to be held longer prior to stocking so testing can be completed. Costs associated with the additional fish health
testing have stressed the limited budgets of Great Lakes resource agencies.
Natural resource agencies have also altered their warm and cool water fish rearing programs in response to the VHSv outbreaks
that have occurred since 2006. The Michigan Department of Natural Resources suspended its muskellunge and walleye rearing
programs in 2007; these programs resumed on a limited basis in 2008 (Gary Whelan, personal communication). Many natural
resource agencies have also limited wild gamete collection to sites that have not tested positive for VHSv, and all agencies have
adopted new egg disinfection protocols to limit the risk of spreading VHSv.
The new regulations have not had a significant impact on salmonid fish operations since cold water species have historically
received fish health inspections.
Conclusions
Viral hemorrhagic septicemia is a new introduction into the Great Lakes, introduced prior to 2003. To date, VHSv has been
confirmed to be present in all of the Great Lakes except Lake Superior, and inland lakes and streams in Michigan, New York,
Ohio, and Wisconsin. The detection of VHSv in Clear Fork Reservoir in Ohio in 2008 was the first isolation of the virus outside of
the Great Lakes basin. The Chicago Waterway links Lake Michigan to the Mississippi River basin, providing an additional entry
point for VHSv to make its way to the Mississippi River. Movement of live fish, including baitfish, will contribute to the spread of
the Great Lakes strain of VHSv through the Great Lakes basin and other regions of the United States and Canada.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Significant fish kills, particularly in spring, are expected to occur as VHSv spreads into these new areas. Additionally, naive fish
populations or year classes will be susceptible to periodic disease outbreaks of VHS in the future.
Acknowledgments
Author: Ken Phillips, La Crosse Fish Health Center, U.S. Fish and Wildlife Service, 555 Lester Avenue, Onalaska, WI 54650
Collaborator: Elizabeth Wright, Fish Health and Aquaculture, Ontario Ministry of Natural Resources, elizabeth.wrightl@ontario.ca
Information Sources
Casselman, J., Lusk, T., Farrell, J., and Lake, C. 2008. Die-off of muskellunge (Esox masquinongy) in the Upper St. Lawrence
River caused by viral haemorrhagic septicaemia, 2005-2007: impacts and consequences. Symposia 15: VHS in the Great
Lakes, 138th Annual Meeting, American Fisheries Society.
Christie, G., Hoyle, J., Bowlby, J., Morrison, B., and Wright, B. 2008.Response of freshwater drum to outbreak of viral hemorrhagic
septicemia (VHS) in Lake Ontario. Symposia 15: VHS in the Great Lakes, 138th Annual Meeting, American Fisheries Society.
Elsayed, E., Faisal, M., Thomas, M., Whelan, G., Batts,W., and Winton, J. 2006. Isolation of viral haemorrhagic septicaemia virus
from muskellunge, Esox masquinongy (Mitchill), inLake St. Claire, Michigan, USA reveals a new sublineage of the North
American genotype. Journal of Fish Diseases 29: 611-619.
Federal Register. 2009. Viral Hemorrhagic Septicemia: Interstate movement and import restrictions on certain live fish. Volume
44 Number 1, January 2, 2009.
Gagne, N., MacKinnon, A-M., Boston, L., Souter, B., Cook-Versloot, M., Griffiths, S., and Oliver, G. 2007. Isolation of viral
haemorrhagic septicaemia virus from mummichog, stickleback, striped bass, and brown trout in eastern Canada. Journal of
Fish Diseases 30: 213-223.
Kayle, K.A., and Wright, M.E. 2008. Predicting and detecting VHS impacts on populations using modeling results: is VHS
mortality separable from M? Symposia 15: VHS in the Great Lakes, 138th Annual Meeting, American Fisheries Society.
Lumsden, J.S., Morrison, B., Yason, C., Russell, S., Young, K., Yazdanpanah, A., Huber, P., Al-Hussinee, L., Stone, D., and Way,
K. 2007. Diseases of Aquatic Organisms 26:99-111.
Meyers, T.R., and Winton, J.R. 1995. Viral hemorrhagic septicemia virus in North America. Annual Review of Fish Diseases 5:
3-24.
Yunker, G., Thomas, M., and Faisal, M. 2008. Effects of VHS on the muskellunge population of Lake St. Clair. Symposia 15: VHS
in the Great Lakes, 138th Annual Meeting, American Fisheries Society.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Figure 1. Cladophora in its growth habit in Lake Michigan off
Milwaukee, Wisconsin.
Source: Image by Harvey Bootsma.
5.4 Cladophora in the Great Lakes: Guidance
for Water Quality Managers
State of the Ecosystem
Introduction
Cladophora is a native, filamentous, green alga that is found
attached to solid substrate in all of the Laurentian Great
Lakes (Fig. I). The alga grows sparsely in a few locations in
Lake Superior (Jackson ct al. 1990). is typically associated
with tributary and point source phosphorus (P) inputs in Lake
Huron (Auer et al. 1982) and occurs as widespread blooms in
the comparatively P-rich waters of Lakes Erie (Higgins et al.
2005a). Michigan (Greb etal. 2004) and Ontario (Wilson ct al.
2006). While Cladophora can successfully colonize offshore
reefs where supported by whole-lake nutrient conditions, it
is the nuisance growths observed in nearshore regions of
Lakes Erie. Michigan and Ontario (Fig. 2) that have drawn
the attention of those involved in public recreation, operation
of utilities and water quality management. Public a\\arencss
of the problem has been heightened by reports in the popular
press of beach fouling and the shutdown of nuclear power
plants, concerns that incidences of avian botulism are linked
to Cladophora. (New York Sea Grant and Pennsylvania Sea
Grant 2001) and scientific studies linking CladophorusinA human pathogens (Hyappanahalli ct al. 2003. Ishii ctal. 2006. Olapade
et al. 2006. Englebert ct al. 2008). Nuisance growth rf Cladophora. with attendant beach accumulation, will demand the attention
of those re-writing the Great Lakes Water Quality Agreement (GLWQA) because the negative effects of the phenomenon are
manifested in a manner and at locations that influence public perception of water quality.
The Historical Context
Cladophora has been known to the Great Lakes scientific community for over 150 years, with nuisance conditions noted as far
back as the mid-20lh century (Taft and Kishler 1973). Regulatory and research interest became more focused with the publication.
in the mid-1970s, of an International Joint Commission (IJC) report entitled. "Cladophora in the Great Lakes" (Shear and
Konasewich 1975). Although the 1978 GLWQA specifically referenced nuisance algae problems and excessive Cladophora growth
was identified as an emerging issue (Task Group III), it was concluded that there was insufficient scientific information available
to develop effective control strategies (Vallentyne and Thomas 1978).
Following publication of the IJC report, the U.S. Environmental Protection Agency and the Ontario Ministry of the Environment
supported a series of scientific and modeling initiatives, seeking to develop a more complete scientific understanding of the
Cladophora problem. The results of these and other studies were presented in a special issue of the Journal of drcat Lakes
Research devoted to the ecology of filamentous algae (Auer 11>S2). It was the general sense of this body of work that the P
management strategies being implemented under the GLWQA could lead to the control of nuisance conditions.
There is evidence that P control strategies have played a role in reducing nuisance conditions of Cladophora growth. Canale and
Auer (1982a) reported a dramatic local decline in Cladophora biomass following implementation of P removal at a wastewater
treatment facility at Harbor Beach, Michigan on Lake Huron. The work of Painter and Kamaitis (1987) strongly suggests that P
abatement efforts had a marked effect on Cladophora in Lake Ontario. They reported that, between 1972 and 1982-83. Cladophora
biomass and Cladophora tissue (stored) P levels declined almost 60% in response to a 67",, reduction in spring soluble reactive
phosphorus (S ) concentrations. l.e\ els of (ladophora biomass observed in 1982-83 were generally at or below the threshold for
nuisance conditions (<50 gDW nr: ct".. Canale and Auer 1982a). If one considers these few reports as representative of the post-P
abatement, pre-dreissenid period, it can be concluded that the management strategies mandated under the GLWQA achieved the
desired effect (cf. Neilson etal. 1995). Interest in Cladophora. as evidenced in the publication record of the Journal of Great Lakes
Research, began to decline in the mid-1980s and the issue of nuisance growths received little attention through the balance of the
20th century.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Resurgence?
A suite of papers recently published in the Journal of Great Lakes Research (Higgins et al. 2005a. 2005b. 2006) and a workshop
convened at the Great Lakes Water Institute of the University of Wisconsin - Milwaukee (Bootsma et al. 2004a) have signaled
a rekindling of attention to the topic of nuisance
Cladophora growth. It is not clear to what degree
renewed interest reflects a true resurgence of the
problem as the relative dearth of data makes it difficult
to compare the magnitude of past Cladophora problems
with those reported currently (Young and Berges 2004).
No systematic, basinwide surveys of Cladophora
distribution and biomass were made during the period of
peak interest and little is known about nearshore P levels
or Cladophora colonization over the period of declining
attention (Higgins et al. 2005a).
It is clear, however, that nuisance growth of Cladophora
is a significant water quality problem as we move into
the 21s' Century. Over the period 1995-2002 (an interval
following dreissenid establishment), the Ontario Ministry
of the Environment supported a series of surveillance
investigations into shoreline fouling by Cludoplmra
in Lake Erie where nuisance blooms were a regular
occurrence. Survey results, published by Higgins ft nl.
(2()05ai. indicate that CUidophi>rn colonizes nearly 100°0
of the available substrate along the north shore of Lake
Erie and that abundance (standing crop) reaches levels
equivalent to those of the 'nuisance growth' period of the
1970s. The Ontario Water Works Research Consortium
initiated studies of the occurrence of Cladophora in
Western Lake Ontario in 2002. In late summer (a sub-
optimal period) of 2003. Cladophora coverage at a
5m depth at 25 locations along the lake's north shore
a\-eraged 57° 0 and attained a greater substrate coverage
than in similar surveys in 1981 and 1991 (Wilson et al.
2006). Anecdotal evidence for Lake Michigan suggests
an increase in Cladophora biomass in recent years (Greb
et al. 2004) with a noticeable increase in the number
of incidents of beach fouling along the Lake Michigan
shoreline (Bootsma et al. 2004b). Today. Cladophora
is abundant along Wisconsin's entire Lake Michigan
shoreline with colonization exceeding 80% in areas of
suitable substrate (Greb et al. 2004) and with nuisance
levels of standing crop (200-400 gDW m:. Bootsma et
al. 2004b).
The high Cladophora abundance in these lakes
is somewhat paradoxical in light of the fact that
concentrations of dissolved P in the pelagic zones
have been declining and. »vith the exception of Lake
Erie, are below the target levels set by the Great Lakes
Water Quality Agreement (Barbiero et al. 2002. Dolan Figure 2. a) Cladophora accumulation along the shoreline of Lake Erie
and McGunagle 2005). This, along with observations (Rock Point Provincial Park), b) Lake Ontario (Coronation Beach), and
of extensive Cladophora coverage in regions that are c) Lake Michi9an (Bradford Beach).
f . Sources: a) Image by Scotl Higgins: b) Image by Sairah Malkin; c) Image by Milwaukee
relatively remote from point nutrient sources (e.g. Greb Metropolitan sewerage District
NEARSHORE AREAS OF THE GREAT LAKES 2009
70
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et al. 2004), suggests that there have been fundamental changes in how nutrients and energy move through these large ecosystems.
These changes may also be reflected in other recent trends, including the decline in plankton abundance in Lakes Huron and
Michigan (Environment Canada and U.S. EPA 2007), declines in the benthic amphipod Diporeia spp. (Nalepa et al. 2005),
changes in the condition of lake whitefish and salmonids (Schneeberger et al. 2005, Claramunt et al. 2007), decimation of the
yellow perch population (Marsden and Robillard 2004), and increased prevalence of type E botulism in fish and birds. Causes of
these various trends require further exploration, but there are plausible mechanisms by which they may be connected (e.g. Hecky et
al. 2004). For example, consumption of plankton by dreissenids may promote Cladophora growth by increasing water clarity and
nutrient supply in the nearshore zone, while at the same time depleting pelagic food resources. Therefore, the problem of excessive
Cladophora growth should not be considered in isolation, but within the larger ecosystem context. While excessive Cladophora
growth is a problem in itself, it may reflect ecosystem changes that have larger ecological and economic consequences.
Pressures
How Does Your Garden Grow?
Like other aquatic and terrestrial plants, Cladophora requires a suite of inorganic nutrients to support growth and flourishes over
a particular range of temperature and light conditions. There is consensus that P is the growth-limiting nutrient for Cladophora in
the Great Lakes (see Higgins et al. 2008 for a review) and P has been and remains the appropriate target for management actions.
Where SRP levels meet the growth requirement lakewide, nuisance conditions may be observed wherever solid substrate is present,
extending to depths where light availability limits growth. Lakewide support of Cladophora growth occurs in Lakes Erie, Michigan
and Ontario (as described above) and management of nuisance growth will require attention to whole lake phosphorus levels. In
cases where SRP levels do not meet the growth requirement lakewide, nuisance conditions occur in the vicinity of point sources of
nutrients, with the extent of colonization being limited by P availability (dilution by whole lake waters) or the light environment
(with increasing depth offshore). As with some other algae, Cladophora has the capacity to store P beyond its immediate needs
(Auer and Canale 1982a). Exposure to transient sources of P (e.g. plume migration and runoff events) for less than one day can
provide sufficient P to support a ten-fold increase in biomass (Auer and Canale 1982b). It should also be noted that mixed conditions
occur where a site is impacted by both whole lake and point source conditions. Managers should bear this in mind when evaluating
the impact of controlling one source of P or the other. The case of nuisance Cladophora growth in the Lake Michigan nearshore
may provide an example of such a case.
The response of Cladophora growth to P availability is non-
linear, an occurrence which has importance when developing
expectations for the outcome of nutrient management programs.
The growth rate of Cladophora increases in a linear fashion as
the amount of stored P increases from its minimum value, then
becomes less sensitive to additional increase in available P and
eventually reaches an asymptote (Fig. 3). From a management
perspective, this figure should be examined from the opposite
direction, i.e. high levels of P availability. Where Cladophora
growth is supported by whole-lake nutrient levels, initial
reductions in available P may not yield a striking response
because the system remains within the P-saturated region of the
curve. Subsequent reductions, however, will place the system
within the linear region where changes in Cladophora growth
will track changes in P loading.
&
m
<£.
s
saturated, unresponsive region
>— linear, responsive region
»minimum P requirement
Phosphorus Availability ->
Figure 3. The relationship between phosphorus availability
and Cladophora growth.
Source: Adapted from Auer and Canale (1982a).
Given an adequate supply of nutrients, Cladophora growth
is governed by conditions of light and temperature. The alga
grows most rapidly in late spring and early summer (May-June in Lake Huron) when water temperatures are in the optimum
range (13-17 °C, Graham et al. 1982). The mid-summer sloughing period (Canale and Auer 1982b, Higgins et al 2005a), where
Cladophora detaches from the substrate and accumulates on beaches, occurs as temperatures reach 22-24 °C (July-August in
Lake Huron). However, no experimentally-verified relationship between sloughing and temperature has been developed, and the
mechanisms responsible for sloughing remain poorly understood (cf. Higgins et al. 2008). Light availability determines the depth
to which Cladophora may colonize substrate at a particular site. An important metric in this regard is the compensation point, i.e.
the light intensity above which net growth is positive. Graham et al. (1982) determined that this critical light intensity lies between
NEARSHORE AREAS OF THE GREAT LAKES 2009
71 —
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25 and 35 fiE-nr2-s"' for temperatures ranging from 5-20 °C. Assuming an incident light intensity of 1000 nE-nr2-s'' and a light
extinction coefficient representative of pre-dreissenid conditions (e.g. 0.46 nr1 for Lake Ontario, Auer et al. 2008), the maximum
depth of colonization by Cladophora would be on the order of 8 m, with optimal light intensities occurring in shallower waters
(1.5-3.0 m). The significance of these growth mediating environmental conditions as influenced through nutrient enrichment and
ecosystem changes with respect to light penetration is discussed below.
Management Implications
Modeling Support for Management
The critical role of mathematical
modeling in providing support for water
quality management is now widely
recognized. A build and measure
approach, where remedial actions are
implemented and assessed iteratively
without guidance from model
projections, has been largely rejected.
This is especially the case for large lake
ecosystems where high costs and long
response times can lead to significant
socioeconomic burdens. For example, P
control measures mandated by the
GLWQA benefited from rigorous model
testing before implementation.
Stored phosphorus mass balance
algal uptake
saturation
feedback
Cladophora
Stored
Phosphorus
partitioning to
new biomass
Algal biomass mass balance
Growth regulation by:
• light
•temperature
• stored phosphorus
•carrying capacity feedback
Loss to respiration (f. light, temperature)
t
Cladophorc
Biomass
•^^^
Loss to sloughing (f. depth, temperature)
Figure 4. A mass balance framework for modeling Cladophora.
The mass balance for ambient soluble reactive phosphorus is presented in Figure 6.
Sources: Adapted and re-drawn from Canale and Auer (1982b) and Tomlinson et al. (2009).
The first model for Great Lakes
Cladophora was developed by Canale
and Auer (1982b; and accompanying
papers). More recently, two modeling
tools (COM, the Cladophora Growth
Model (Higgins et al. 2005b) and GLCM,
the Great Lakes Cladophora Model
(Tomlinson et al. 2009)) have been developed by
expanding on and revising that framework. The CGM
was applied to Lakes Erie (Higgins et al. 2005b) and
Ontario (Malkin et al. 2008) and the GLCM to Lakes
Huron and Michigan (Tomlinson et al. 2009). CGM
and GLCM developers joined forces in a binational
effort to examine the impacts of P management and
ecosystem changes associated with the proliferation of
dreissenids (Auer et al. 2008, discussed below).
Models for Cladophora in the Great Lakes are based
on the principle of mass balance, a concept which
may be likened to a checking account, i.e. the rate of
change in the account balance is equal to inputs from
deposits less outputs to checks written plus or minus
changes due to 'reaction' such as interest or fees for
bad checks. In its application to Cladophora (Fig.
4) the mass balance includes inputs (or gains) due to
growth, outputs (or losses) due to respiration and a
loss 'reaction' associated with physical detachment
(sloughing). The mass balance itself is straightforward; however, characterization and quantification of the factors mediating the
input, output and reaction terms (e.g. the roles of light, temperature and nutrients) must be well supported by science. While it
NEARSHORE AREAS OF THE GREAT LAKES 2009
•o
o
Added
Scientific
Support
Model Complexity
Figure 5. The relationship between model complexity and model
reliability, illustrating the role of scientific studies in improving reliability.
Source: Adapted, modified and re-drawn from Chapra (1997).
— 72 —
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may seem that the more comprehensive (i.e. complex) a model becomes, the better it represents nature, adding complexity without
appropriate scientific support leads to a decline in model reliability (Fig. 5), an important concern in management applications.
The art in modeling (and perhaps in managing) is to select an approach that resides at the optimum position on the complexity-
reliability continuum.
Not Your Mother's Ecosystem
Research efforts in the 1980s and 1990s made it clear that the distribution and abundance of Cladophora were governed by P
availability (Auer and Canale 1982a, b, Painter and Kamaitis 1987) and the underwater light climate (Graham et al. 1982, Lorenz
et al. 1991). It has been concluded from hindcast modeling (Auer et al. 2008) that P loading reduction mandated under the GLWQA
achieved the desired effect with respect to nuisance conditions. It is also clear, however, that nuisance Cladophora growth has today
reclaimed its position as a serious water quality problem in the Great Lakes. Scientists familiar with the ecology of Cladophora
have recognized that changes in the Great Lakes associated with the dreissenid invasion could have profound (Lowe and Pillsbury
1995, Higgins et al. 2005a, b) and previously unrecognized (Hecky et al. 2004, Higgins et al. 2008) effects. Dreissenid mussels can
potentially impact Cladophora growth by providing substrate for attachment (Wilson et al. 2006), altering pathways of P cycling
(Hecky et al. 2004) and modifying the underwater light climate (Holland 1993, Howell et al. 1996, Auer et al. 2008).
With respect to alteration of the underwater light climate, the case is undeniable. Auer et al. (2008) estimated that, following the
establishment of dreissenids, the average light attenuation coefficient for Lakes Erie, Michigan and Ontario dropped from 0.46
to 0.29 per meter, extending the depth to which Cladophora could colonize substrate by 6 m. Model calculations indicated a
corresponding increase in Cladophora growth potential of ~50%, an amount sufficient to significantly offset reductions in growth
potential achieved previously through management of P loads.
A second effect, alteration of pathways for P cycling, remains an intriguing, but unproven hypothesis. The underlying premise is
that filtration of the water column by mussels, with subsequent excretion of soluble phosphorus (the nearshore P shunt, Hecky et
al. 2004) would provide a source of P for Cladophora that was previously unavailable. The hypothesis is intellectually satisfying
because mussels have the potential to capture and recycle particulate inorganic P originating from nearshore sources that would
historically have been transported to offshore depositional sites before being solubilized and made available to the algae. Further,
mussels capture and recycle particulate organic P in the form of phytoplankton, an activity which may promote Cladophora
growth by increasing dissolved P availability (Heath et al. 1995, Arnott and Vanni 1996) while eliminating a competitor for those
resources.
Into the 21st Century
Managers seeking to control the nuisance growth of Cladophora will encounter a Great Lakes ecosystem profoundly changed
by the proliferation of dreissenids. A binational modeling study (Auer et al. 2008) concluded that gains made through P loading
reduction have been offset by dreissenid-driven changes in water clarity that extended the depth of colonization of Cladophora,
increasing total production. Attendant impacts relating to dreissenid mediation of P cycling have not been isolated and identified.
Barring a dramatic reduction in mussel abundance, it is unlikely that the Great Lakes light environment will return to pre-
dreissenid conditions. This leaves the management of nearshore P levels as the only means of addressing the conditions of nuisance
Cladophora growth presently experienced in Great Lakes waters. That management effort will require an integrated program of
scientific study, mathematical modeling and field monitoring to establish targets for P control and to assess the efficacy of remedial
measures. Such a program would also inform other management decisions not directly related to Cladophora. For example, an
improved understanding of P and carbon exchange between the pelagic and nearshore zones will provide insight into how plankton
consumption by dreissenids may affect food supply for pelagic and nearshore fish communities.
Hindcast Assessment
No systematic, comprehensive, basinwide monitoring programs for Cladophora have ever been implemented. Our knowledge
of the extent and magnitude of the Cladophora problem consists of observations by individual investigators at isolated sites
and regional surveys conducted by state and provincial authorities for limited periods. Because of this, scientists exploring the
apparent resurgence of Cladophora cannot confidently state that conditions have truly worsened, only that nuisance conditions
are occurring at present (cf. Auer et al. 2008). It would be prudent, as a prelude to development and implementation of new P
management strategies, to utilize archival remote sensing data (see below) and hindcast modeling to properly characterize the
development of today's conditions.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Supporting Science
Development of a management plan for Cladophora
in the Great Lakes nearshore will be guided by
model simulations, testing the system response to
changes in P loads. The current models incorporate
a framework linking external P loads to the ambient
nutrient concentration to which the alga is exposed
(Fig. 6). That framework is no longer complete in
its description of those linkages. Scientific studies
will be required to describe the role of the nearshore
shunt in mediating P dynamics, identifying and
quantifying pathways that have evolved with the
advent of dreissenid populations. This new framework
should accommodate the transformation of in-lake
(i.e. phytoplankton) and watershed (i.e. terrigenous)
particulate P to S^, (dashed lines in Fig. 6) and the
dynamics of Cladophora utilization of that P (ambient
SRP -» P stored in the alga) in the post-dreissenid
ecosystem.
NPS
Ambient
S
NPS
Phytoplankton
Phosphorus
offshore
and
>— longshore
mass
transport
Figure 6. Conceptual model for soluble reactive phosphorus (SRP) and
particulate phosphorus (PP) dynamics in the nearshore.
Dashed lines indicate changes to the phosphorus cycle hypothesized
to have resulted from dreissenid colonization (i.e. the nearshore
phosphorus shunt, NPS).
Source: Adapted from concepts developed by Hecky et a/. (2004).
In addition to science that directly supports Cladophora models, there is a need for research that addresses eco-dynamics in
nearshore zones supporting large amounts of benthic algae biomass. This growth sequesters a significant amount of P and produces
large amounts of organic carbon, but the fate of these materials is unknown. Critical questions include the contribution of this
carbon and P to the nearshore food web, and the effect of decomposing algae on dissolved oxygen and redox conditions in the
nearshore benthos.
Modeling
The Cladophora models currently available to the management community (COM and GLCM) compare favorably with those
routinely applied in simulating nutrient-phytoplankton dynamics in offshore waters. The nature of the Cladophora issue requires
that only a single species be addressed, making a rigorous characterization of the alga's physiology more tractable (although recent
outbreaks of other filamentous algae, such as Lyngbya sp., in Lake Erie may eventually expand the need for physiological and
ecological studies). The reliability of Cladophora models for management applications would benefit from additional consideration
of sloughing mechanisms and from further testing of model capabilities in simulating the response to the light environment in the
post-dreissenid era.
The true challenge from a modeling perspective is to place the subroutines describing P kinetics within the context of a nearshore
P model. Here, the model would simulate ambient SRP conditions by accommodating TP loads, cycling of particulate P through
the dreissenid shunt, uptake of Sgj, and horizontal and vertical transport. The only extant example of such an application is that
of Canale and Auer (1982b) for a site on Lake Huron, however this framework does not include cycling by dreissenids and the
treatment of mass transport would be considered quite simple by today's standards. It will be necessary to integrate models for
Cladophora growth with newly-developed information on P cycling and couple these with a nearshore hydrodynamic (mass
transport) model.
Monitoring
Efforts to manage nuisance growth of Cladophora through P management must be supported by a comprehensive and systematic
monitoring program, documenting biological, chemical and physical conditions over a statistically-defined grid in time and
space. The appropriate metric for assessing the status of the Cladophora problem is annual biomass production, as it is this that
determines the quantity of algae available for transport to the extreme nearshore, fouling beaches and clogging water intakes. It
is infeasible to measure production directly; however, it may be estimated as the product of the alga's areal coverage, its biomass
density and its growth rate (~ P status).
It is believed that extension of areal coverage to new habit has occurred in response to dreissenid-induced increases in transparency.
Reductions in ambient P levels, resulting from newly-implemented management programs, will stress Cladophora populations
NEARSHORE AREAS OF THE GREAT LAKES 2009
74
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colonizing substrate at the lower limits of available light, leading to a reduction in areal coverage. Areal coverage may be effectively
monitored through remote sensing using established (Fig. la. cf. Lekan and Coney 1982) and emerging technologies (Fig. 7b).
Monitoring biomass density, in a manner similar to that for chlorophyll in pelagic habitats, has historically been a favored metric
for assessing the status of Cluduphom populations. Biomass density presents particular challenges with respect to Cladophora,
however, because substrate is irregularly colonized (sand/silt patch, uncolonized solid substrates) and because the stochastic
sloughing phenomenon uncouples standing crop from production. These challenges may be overcome by expanding the space
and time scale of the monitoring program, but this is logistically prohibitive. Benthic sampling often requires SCUBA, which is
technically more demanding and time-consuming than conventional water quality sampling with bottles deployed from a research
vessel. The most promising avenue in this regard may be evolving remote sensing technologies that can quantify biomass as well
as areal coverage.
P status may be one of the most powerful metrics for assessing the status of Cliulophora as the relationship between stored P and
growth (and thus production) is well defined. Because the alga has the capability to accumulate P beyond its present needs, stored P
levels provide an integrated picture of the ambient SR[, environment (information not available from grab samples of ambient SRP).
This approach was successfully used to assess the response of Cladophora to P controls in Lake Ontario (Painter and Kamaitis
1987). Monitoring of stored P also offers advantages logistically as the required level of sampling intensity is more tractable.
However, it is important that irradiance is also monitored, as light availability alters the relationship between ambient dissolved P
and CUulophiira P status (Bootsma el ul. 2004b).
Summary
Cladophora is a filamentous alga that grows attached to solid substrate in nearshore waters and on offshore reefs in the Great
Lakes. Where P resources are sufticient. the alga can grow to nuisance proportions, fouling beaches and clogging water intakes.
It is believed that P management efforts implemented in the latter decades of the 20Ih century were successful in reducing the
frequency of nuisance conditions. C'hanges in the underwater light climate, occurring in response to colonization by dreissenids.
permitted (.'Uhloplwni to expand its range and increase overall production to levels that resulted in significant beach accumulation
and problems with water intake structures.
Management of the apparent resurgence in Ckuhplwrn growth will appropriately focus on further reductions in ambient levels of
S . The identification of target loads for P should be guided by mathematical models ofCIaduplioni growth. It will be necessary to
couple those models with simulations of nearshore P dynamics, taking into account the role of dreissenids in mediating P cycling.
Emerging remote sensing technologies and on-site measurements of the stored P content of the alga hold promise as a means of
assessing the response of CUutophora populations to management actions.
Figure 7. Remote sensing of Cladophora.
a) aircraft-generated, multispectral scanner output for Lake Huron at Harbor Beach, Michigan.
b) Platte River mouth, Lake Michigan.
Sources: a) Lekan and Coney (1982); b) Digital Globe, 2003. Pan-sharpened color image of Platte River Point from a June 2": 200 Digital G
Retrieved using Google Earth Professional on July 25, 2008.
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Acknowledgments
Authors:
Martin T. Auer, Ph.D., Michigan Tech
and
Harvey A. Bootsma, Ph.D., Great Lakes WATER Institute University of Wisconsin-Milwaukee
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5.5 Harmful Algal Blooms (HABs) in the Great Lakes:
Current Status and Concerns
Introduction
Cyanobacterial and algal1 blooms are a long-standing issue in eutrophic waters with high anthropogenic or natural nutrient loading.
Widespread blooms (planktonic and attached, e.g.. Cladophora) were a recognized impairment in offshore and nearshore areas in
the Great Lakes in the 1960s and 1970s (e.g.. Munawarand Munawar 1996. 2000, Higgins et «/. 2008). Concerns at that time were
based around impaired aesthetics; taste and odour (T&O); foodweb decline: fouling of beaches, water intakes and fishing nets;
and economic impacts. These were addressed largely by targeting total phosphorus (TP) and chlorophyll a (chlo) levels, mitigated
through reductions in point-source nutrient loadings. Recently, however, there has been an apparent resurgence in algal blooms
in parts of the Great Lakes, accompanied by the potential production of toxins or harmful metabolites, compounds which were
unidentified in the 1970s. In fact, there is a widespread perception- that harmful algal blooms (HABs) are increasing worldwide
(e.g., Hallegraeff 1993) and that they may be linked to the cumulative effects of human development.
Definition of HABs
There are no quantitative definitions of HABs. With current publicity, the terms 'HABs'. 'harmful' and 'bloom' are often used
synonymously in reference to all types of algal outbreaks. In fact, 'bloom' is an ambiguous term, currently defined only by
qualitative descriptors (e.g., Smayda 1997). Pearl (1988) further differentiates 'harmful' from 'non-harmful' blooms by their
qualitative impacts on: i) water quality, biota or physico-chemical characteristics; ii) health risks from toxins or heightened
microbial activity; or iii) aesthetics or recreation.
HABs in the Great Lakes are generally associated with planktonic toxic cyanobactcria, but HABs involve a variety of species
and are particularly problematic in coastal areas. These events are often highly sporadic and dynamic in nature, showing episodic
patterns which vary seasonally and annually in severity and geographical range. Importantly, as a coastal phenomenon, their
appearance is often unlinked with current monitoring targets. Great Lakes monitoring programs continue to evaluate planktonic
(subsurface) ch\a as a measure of total algal biomass and productivity, but that metric is often irrelevant to identifying HABs.
Impacts can include: risks to human and animal health via toxins, carcinogens, teratogens. or irritants in drinking water; other
drinking water impairment (T&O, aesthetics); fouling of water intakes, fish nets and shoreline; bacterial growth in rotting mats
(including potential pathogens, e.g., E. coli); beach closures (affecting recreation and tourism): tainting offish, shellfish, and
processed food (harming commercial and recreational fisheries and other food industries); food web integrity and structure, and
environmental degradation such as anoxia. HABs thus include Cladophora, other benthic or littoral macroalgal proliferation, and
planktonic blooms. All represent current concerns in the Great Lakes and are addressed below.
State of the Ecosystem - Harmful Algal Blooms
Background
The ability of HABs species to proliferate is dependent on the nature of the environment and its seasonal and spatial variance. The
operational definition of the nearshore zone thus has an important bearing on assessing, monitoring and managing HABs. In the
Great Lakes, the nearshore has been statically defined as the zone between the edge of the shoreline or wetlands and the deepest
lake contour at the late summer thermocline (if established). It includes connecting channels and waters, lower tributaries and
unstratified areas around islands and shoals (Edsall and Charlton 1997). Yet in function, these coastal regions are highly dynamic.
with long- and short- term spatially and temporally variable boundaries
The size of nearshore zones varies enormously among and within the Great Lakes (-1-10% of Lake Superior to 60-90% of Lake
Erie, Edsall and Charlton 1997), as does the degree to which each zone is influenced by physical and climatic factors (e.g., runoff
erosion; thermal bar; upwelling and downwelling; alongshore, nearshore. and offshore currents; circulation patterns; surface and
ground water inputs; ice formation). This translates to a highly variable littoral community structure and activity. Nearshore
1 'Algae' in this paper denotes both cukaryotic algal taxa and eyanohacteria.
2 Toxins are only recently recognized as a threat from algal blooms. With few historical data, this perception is based more on anecdotal evidence and not
quantified information. Reports may be biased due to increasing public awareness. Most sites are not monitored, many blooms are not identified, and visible
blooms are not the only sources of the toxins.
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biotic assemblages are further shaped by regional differences in bottom substrate, daily and seasonal ranges in water levels and
temperature, and impacts of human development on the shoreline (e.g., deforestation, agriculture, industry, urbanization, wetland
drainage and dredging, water level regulation). The lower Great Lakes are considerably more impacted by human disturbance, and
they are also significantly more prone to algal blooms.
Biochemical impacts of HABs
T&O compounds and toxins are often assumed to be manageable by controlling excess algal growth. However, there is often a very
poor relationship between algal biomass and the presence of these metabolites. Their production may involve a variety of genetic
and biochemical pathways, the same or different taxa, and cell-specific variability in production capacity and output, which is also
related to genetics and environmental factors (Watson 2003).
Toxicity, T&O or other impacts are difficult to predict. One or more of ~200 known toxins and T&O compounds are produced
by many different species, but current resources and knowledge limit our ability to characterize and evaluate impacts. The issue
is complex and effective field sampling is difficult. Outbreaks can be episodic, erratic and involve planktonic or benthic biota.
Incidence and levels of toxins, T&O, visible blooms, and algal abundance (cell counts, biomass, or chla) may or may not be
related. For example, Microcystis does not produce 'earthy' T&O (geosmin and 2-MIB) and is often odourless, while odour-
causing species (e.g., Anabaena, Lyngbya) may or may not be toxic. Genetic capacity and cell production can vary for toxins and
T&O among species, cell populations and environments. Potential producers and morphologically similar species co-occur,e.g.,
Microcystis aeruginosa and M. wesenbergii4, Anabaena flos-aquae and A. lemmermanii (e.g., Rinta-Kanto et al. 2005, Jiittner and
Watson 2007). Variance among analytical and sampling methods often generates inconsistencies among reported levels (G. Boyer
unpublished data).
Toxins
Cyanobacterial toxins have no taste or odour. Because they were identified relatively recently, there are no long-term records, hence
any long-term changes in severity and occurrence are difficult to verify. They were unknown when beneficial use impairments
(BUI) were defined for Areas of Concern (AOCs), and they are still largely not addressed by most Great Lakes management
programs. Current (and limited) sampling is often reactive, often fails to capture episodic events, and is biased towards research
in high-risk areas. Yet concern has been growing since the first report of a toxic outbreak in western Lake Erie (Brittain et al.
2000). Recent lakewide surveys since 2000 (e.g., MERHAB-LGL, EC)3 found detectable toxin levels in many areas, especially in
the Lower Lakes or coastal areas with moderate to severe impairment (Boyer 2007, Watson et al. 2008a, b). Toxin levels at most
offshore sites are generally very low, but in nearshore zones with advanced eutrophication (e.g., harbours, embayments and river
mouths, including Bay of Quinte, Oswego Bay, Sandusky Bay, Maumee Bay, Saginaw Bay, and Hamilton Harbour) they can often
exceed drinking water guidelines, particularly where present as surface or windblown shoreline scums.
The most commonly reported toxins in the Great Lakes and other waters are microcystins (MC). Exposure though ingestion or
inhalation can cause liver failure and death or increased risk of cancer with long term chronic exposure. Numerous structural
variants differ in toxicity.4 Microcystin-LR (MC-LR) is the most widespread and toxic and is the basis for many guidance levels
(Codd et al. 2005). MCs are produced by a range of cyanobacteria species, some of which cause outbreaks in the Great Lakes,
notably Microcystis spp. (e.g., Boyer 2007). MC and hepatotoxic nodularin are stable, even to boiling, and may impair food webs.
Guidance levels are few and vary among agencies,5 especially for recreational areas with high public exposure and risk. In Lakes
Ontario and Erie, neurotoxic anatoxin-a and saxitoxins have been detected at both high and low levels (Boyer 2007, Watson et al.
2008a, b). There are no data on the occurrence of lipopolysaccharides (LPS), produced by all cyanobacteria and widely believed to
cause gastroenteritis, skin and eye irritations, hay fever, asthma and blistering (although this is debated, e.g., Stewart et al. 2006).
3 NOAA Monitoring and Event Response in the Lower Great Lakes; Environment Canada.
4 >90 MC variants (congeners) now identified.
5 E.g., WHO, Health Canada GLs for total MC of 1-1.5 ng/L for treated drinking water respectively; recreational water -10- ±20 jig/L; Watson et al. ibid;
currently still on the U.S. EPA Critical Contaminant List.
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Taste and odour
T&O impairment is widespread in the Great Lakes. Most of the recorded outbreaks and incidental reports of this impairment have
not been traced to their biological origin(s). T&O compounds have no known human health effects, but can impart significant
consumer alarm and drinking water treatment costs (e.g., Engle et al. 1995). T&O compounds, however, can function in foodwebs
as powerful chemical signals, acting as grazer deterrents or toxins (e.g., Watson 2003). Numerous algal volatile organic compounds
(VOCs) are known, which vary in odour, potency, seasonal dynamics and treatment implications. One or more planktonic or
benthic species may co-produce different VOCs, which may be cell-bound until death, continuously released, or triggered only
by cell lysis. Benthic and planktonic diatoms and chrysophytes can produce lipid derivatives6 causing fishy or cucumber odours
in low to moderately productive waters. In remediated, mesotrophic and eutrophic waters such as the Great Lakes, T&O is caused
frequently by terpenoids7 (geosmin, 2-methylisoborneol (MIB)), and to a lesser extent, pigment derivatives (p-cyclocitral)7 or
methyl- and isopropyl sulphides8. Hidden or detached benthic, littoral and epiphytic cyanobacteria (e.g., Lyngbya, Oscillatoria,
Gloeotrichia) are significant geosmin and MIB sources in nearshore areas of the lower Great Lakes and channels (St. Lawrence
River, Maumee River, Bay of Quinte, Watson et al. 2005 and unpublished data) affecting shorelines and drinking water supplies.
The anaerobic breakdown of any excessive bloom material is also a frequent T&O source. Rotting mats of Cladophora, Lyngbya
and other attached algae are major sources of septic, sewage or sulphur odours along beaches and shorelines in the Great Lakes
and connecting channels, driven inshore by wind or currents.
Most jurisdictions have not regulated T&O, and there are no quantitative guidance levels in drinking or recreational waters. T&O
is listed under the Canadian Drinking Water Quality Guidelines "aesthetic effects" and is a listed BUI (treated municipal supplies).
T&O impairment occurs in over a third of AOCs, mostly in the Lower Lakes, but likely is more widespread (Watson et al. 2007,
Watson et al. 2008a, b). There has been little or no direct monitoring or quantification of T&O, other than by some drinking water
treatment facilities, and it is usually deduced by environmental assessment programs (e.g., Remedial Action Plans (RAPs)) using
often unrelated measures (e.g., chkr, nutrient levels, Keene 2002, Watson et al 2008a,b).
Great Lakes: current status of HABs in individual lakes
As noted above, there are no long term trends in toxins and T&O because HABs data are limited. Hence, only a qualitative
assessment of the current status in each Lake can be made here.
Lake Superior - Status: good
There is very little quantitative current information on HABs in Lake Superior. To our knowledge, severe HABs outbreaks
have not been documented recently in Lake Superior, although cyanobacteria, including Mcrocystis, are detected in samples
taken during routine monitoring. Algal biomass remains mostly at low levels, although there may be some local impairment
near shoreline development (J. A. Thompson and J. Kelly, U.S. EPA MED, Duluth, personal communication). A recent survey of
drinking water utilities showed few reported T&O issues, which may or may not be of algal origin. Intermittent outbreaks have
been reported from one drinking water utility (Moore and Watson 2007).
Lake Michigan - Status: mixed
Lake Michigan has a fairly extensive nearshore zone as defined by the 9 m or 27 m depth contour (10%, 26% area, respectively),
which nevertheless only accounts for a small fraction of the total volume (0.4%, 4%, respectively). Yet the nearshore area has a key
influence on the lake ecosystem. Lake Michigan has the largest groundwater input (79% hydrological loading) due to nearshore
aquifers, and water levels recently have been lower than long-term normal. Resuspension during mixing and storm events
generate extensive late winter-early spring plumes of resuspended sediments along the eastern shore, which have a significant
effect on the light regime and nutrient cycling and transport. These events also influence the biological community by introducing
resuspended diatom plumes characteristic of more eutrophic waters and modifying the spatial distribution of other phytoplankton
and microbiota. Cyanobacteria blooms are reported in some coastal regions in eutrophic embayments such as Green Bay and
Muskegon Bay. Shoreline and beach fouling by Cladophora, stimulated by nutrient loading from nearshore sources, represent a
6 Synthesized during lysis.
7 Synthesized over growth and mainly cell-bound.
8 Synthesized over growth and continuously released.
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potential source of bacteria for beaches and groundwater by trapping bacterial flora (washed in from runoff and other sources)
during their growth, which are then deposited along shores by currents and storms.
Lake Huron - Status: mixed
Lake Huron is one of the more oligotrophic of the Great Lakes, yet excessive phytoplankton and potentially toxic HABs occur in
some nearshore areas, notably Saginaw Bay and Northern Georgian Bay (Fahnenstiel et al. 2008, Scheiffer and Scheiffer 2002).
These two areas differ markedly in drainage basin development, HABs species, and associated impairment. Saginaw Bay has a
large and extensively developed catchment, and it develops toxic summer outbreaks of Microcystis aeruginosa. These blooms
appear to be genetically distinct with a greater MC production capacity than HABs populations of M. aeruginosa in other Great
Lakes, e.g., Western Lake Erie (Dyble et al. 2008, Fahnenstiel et al. 2008). Highest toxin levels occur in shallow regions with
high TP concentrations. Northeast Georgian Bay watershed is far less developed, but it has extensive wetlands and a growing
cottage industry. The region has generally good water quality, but a few nearshore areas show high TP and chla levels, including
Sturgeon Bay (Diep et al. 2006). The upper stratified basin of Sturgeon Bay experiences hypolimnetic anoxia, accompanied by
sediment nutrient release and severe annual blooms during fall turnover, which impair shorelines and water quality (Schieffer
2003). Samples collected during a partnered MOE-EC two-year characterization of these blooms showed a predominance of
diatoms, N-fixing Aphanizomenon and Anabaena. Toxin levels (MC, Anatoxin-a) were at or below detection over the entire season
(Watson and Howell 2007).
Similar to Lake Superior, there are few issues with drinking water T&O outbreaks in Lake Huron, with outbreaks reported at a
single area (Moore and Watson 2007). However, macroalgal impairment is a major concern in some areas. Recently, complaints
of fish-net fouling by attached chlorophytes have increased (Spirogyra cf. circumlineata, Stigeoclonium; Watson and Milne
unpublished). Rotting mats of beached green macroalgae are increasingly impacting aesthetics, recreation and tourism along
some shorelines. Notable occurrences were observed along Saginaw Bay and, more recently, along the southeast coast, largely
caused by Cladophora and Chara, respectively. Recent studies by United States and Canadian agencies (MDEQ, MNR, OME,
EC) have raised new concerns about the health implications of these events due to the detection of human fecal indicators (E. coli,
Enterococcus) and evidence of differential survival in the beached mats and in situ beds of the macroalgae (Lake Huron Binational
Partnership 2008-2010 Action Plan 2008). Patchy sites have also shown elevated E. coli counts associated with algal debris buried
in beach sand. There is a perceived increase in the range and severity of these events, which demonstrate different patterns, thereby
suggesting that several (unresolved) factors contribute to the problem. Cladophora is more clearly associated with suspected
nutrient discharge, while Chara is more widespread and not clearly linked to local inputs (Howell et al. 2005).
St Clair River/Lake St Clair/Detroit River - Status: fair to good
Recent reports and surveys do not identify algal blooms as a problem, and chla levels are generally low (-3-5 ug/L; Lake St.
Clair Canadian Watershed Coordination Council 2005, Watson unpublished), although there is some spatial variance. However, a
summary report issued in 1999 reported 'floating mats of submersed aquatic plants and algae' along the Western shoreline,9 and
several utilities report annual or intermittent T&O in water drawn from the St. Clair and Detroit Rivers (Moore and Watson 2007).
Lake Erie - Status: mixed to poor
Water levels in Lake Erie typically fluctuate about 36 cm/yr, but in some years up to 50 cm (e.g., 2002). There has been a steep
decline in levels from a 1997 peak to below average during recent years, with significant fluctuations due to climate and storm
events. This, together with the corresponding dynamics in the physical and chemical regime, has been accompanied by some
disturbing trends in biota and system integrity. Not only does Lake Erie have the most extensive nearshore area, but toxic HABs
are a particular concern and the focus of several recent studies. These studies have provided more insight into these events than
for the other Lakes.
HABs biomass and impairment in Lake Erie
General trends: The operative definition of the nearshore area includes 60-90% of Lake Erie, including most of the Western Basin.
Collective evidence points to important recent changes in coastal areas and the dynamic nature of the functional nearshore zone.
Overall, the data indicate an apparent deterioration of the physical, chemical, and biological regimes, notably in the Western basin.
These are not easily assessed using current monitoring methods and measures, which may provide contradictory or ambiguous
9 Lake St. Claii: Its Current State and Future Prospects conference summary report 1999; http://www.great-lakes.net/lakes/stclairReport/summary_OO.pdf
NEARSHORE AREAS OF THE GREAT LAKES 2009
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evidence, particularly where basin-wide averages and/or surface (1 m) chla concentrations are considered (Ghadouani and Smith
2005). Makarewicz (1993) reported a 70-98% reduction in the biomass of nuisance and eutrophic 'indicator' species10 in the 1980s
(e.g., diatoms Stephanodiscus binderanus, S. niagarae, S. tenuis, and the cyanobacterium Aphanizomenon flos-aquae), which
generally correlated with TP levels. Other studies also suggest a decline in overall chla levels and total or eutrophic species
biomass in the Central and Eastern basins, which has been attributed to nutrient reduction, increased water transparency and
grazing by invasive dreissenids. Conroy et al. (2005a) evaluated trends in biomass and chla data (covering studies in 1970,
1983-88/89,1989/90-93,1996-2002) and concluded that average biomass has generally increased in all basins since the late 1980s
minima. They also observed no consistent relationship between algal biomass and dreissenids or external TP loading (total or
basin-specific), and they suggested that internal loading is becoming more important (e.g., Makarewicz et al. 2000, Matisoff and
Ciborowski 2005). However, Conroy et al. (2005) also highlight different patterns among basins and seasons underlying basin-
wide averages. Spring algal biomass in the Western basin decreased markedly in the 1980s to 1990s, but approached previous
maxima in 2000-2002. Summer algal biomass also decreased significantly during the same time period, but then increased to
about 50% of the earlier maxima. A similar, slightly less significant resurgence occurred in the Central basin. The Eastern basin
showed a more variable interannual pattern, with an aUrtime maxima in the late 1990s. Recent levels (2000s) were still elevated.
These generalized patterns overlay significant spatial (horizontal and depth-related) variance among sites, particularly along
shorelines and in the Western Basin (e.g., Carrick et al. 2005, Ghadouani and Smith 2005).
Cyanobacteria: Pre-remedial (1970s) summer-fall high cyanobacterial biomass was reported by Munawar and Munawar (1996),
with a predominance of N-fixers (Aphanizomenon, Anabaend) and regional maxima indicating localized development or
translocation by currents in the Western basin (Maumee-Peele; Sandusky), West-Central basin and Eastern basin (Erie, Buffalo).
'Bloom proportion' cyanobacterial levels (> 1000 ug/L) were reported only in the Western basin and far Eastern basin (Buffalo).
Diatoms were dominant. Recently, Conroy et al. (2005) reported a resurgence in cyanobacterial biomass in all basins in summer
since the mid-1980s, notably in the 2000s.
Again, there was high interannual and spatial
variability, but an overall increasing frequency
of high cyanobacteria biomass (which may also
reflect targeted sampling). Both total algal and
cyanobacterial biomass showed no significant
relationship with external TP loading and a
poor relationship with chla levels. Most of
the increase in summer cyanobacteria was
attributed to Mcrocystis spp., suggesting a
long-term shift from N-fixers in the 1970s
to non-fixers. This shift may reflect changes
in nutrient supply or dreissenid activity. A
1998 survey by Barberio and Tuchman (2001)
also showed a predominance of Mcrocystis
and other chroococcales (Aphanocapsa
delicatissima, Chroococcus Hmneticus).
Toxins: Lake Erie and associated channels
and embayments are among the most severely
HABs-impacted areas of the Great Lakes (e.g.,
Table 1). July to October outbreaks of planktonic
and benthic taxa show significant interannual,
seasonal and spatial variation in origin and
impacts. Immense surface blooms (> 20 km2)
have been recorded in the Western basin near
the Maumee and Sandusky Rivers, which are
potential sources for HABs in Western and
Cruise, date
Brittain
MELEE-VII
MELEE-VIII
Lake
Guardian &
OSU
MELEE-IX
Limnos
Sep-
96
Jul-02
Jul-03
Aug-
03
Jul-04
Aug-
04
#
samples
44
119
59
48
40
13
toxin
MC
MC
ATX
PSTs
MC
ATX
MC
ATX
MC
ATX
CYL
MC
ATX
CYL
%
samples
toxic
10
7
14
0
41
5
60
4
38
33
0
85
31
15
max
level
jig/L
3.4
0.7
0.04
0.65
0.11
21
0.2
>1
0.6
2.4
0.07
0.18
Comments
WB only
whole lake; highest
at Sandusky, Long
Ft., Rondeau Bays
whole lake; highest
in WB & Sandusky
Bay
WB only, highest
nr. Maumee R.
Highest nr.
Maumee &
Sandusky Bay
WB only
MC=Microcystin; ATX=anatoxin-a; PSTs=saxitoxin + neosaxitoxin;
CYL=cylindrospermopsin
Table 1. Summary of toxin levels in Lake Erie from 5 surveys.
Source: Boyer (2007).
10 See section on indicator species below
NEARSHORE AREAS OF THE GREAT LAKES 2009
82
-------
West-Central basins (e.g., Rinta-Kanto et al. 2005). Data from five targeted cruises during 2000-2004 measured a wide range
in MC levels from detection limits (in 2002) to > 20 ug /L (in 2003). Toxicity and bloom distribution varied spatially and were
not restricted to the Western basin. In 2003, highest MC concentrations were measured from Maumee Bay, Long Point Bay
and Sandusky Harbour. Neurotoxins (anatoxin-a, saxitoxin, neosaxitoxin) and cylindrospermopsin occurred at or near detection
limits. In 2001 and 2002, some significant localized MC occurrences were also reported from the Central and Eastern basins
(Wendt Beach, Presque Isle, Port Dover; Murphy et al. 2003, Ghadouani and Smith 2005).
Variance in toxicity among species and strains means that microscopic identification, biomass or cell counts cannot predict toxin
levels. MCs are the most common cyanobacterial toxins measured in Lake Erie. Recent work reported toxic Microcystis blooms
from Maumee Bay with 5-100% variance in genetic potential for MC production and suggested that these blooms were the likely
MC sources in far west and Long Point areas. In contrast, in Sandusky Harbor, subdominant Planktothrix and/or other unidentified
taxa were the likely MC sources where cyanobacteria were dominated by non-MC producers (Aphanizomenon, Anabaena; Rinta-
Kanto et al. 2005, Rinta-Kanto and Wilhelm 2006, Boyer 2007). Most impairment occurs at shorelines and beaches and can be
manifested as fish or bird kills (e.g., Murphy et al. 2003). To date, however, Lyngbyatoxins (which can be inflammatory, vesicatory
and tumour-promoting) have not been detected, including in the extensive mats ofLynbya wollei now proliferating in the Maumee
Bay.
Spring and late fall samples are often overlooked, yet some species can show significant development during this period.
Cylindrospermopsis raciborskii, first identified in Sandusky Bay in 2005, may develop localized high spring biomass (Conroy et
al. 2007). This N-fixing species has a wide temperature tolerance (up to 30°C) and high P storage capacity. It is invading north
from warm to mid-latitude regions and has a strain-specific potential to produce cylindrospermopsin, mediated by light (Dyble et
al. 2006). Cylindrospermopsis is buoyancy-controlling, like Microcystis, but better adapted to turbid conditions, and it is found
near rivers and as deep chlorophyll maxima in stratified waters. Therefore, it may be missed by discreet depth sampling regimes
of current surveillance programs. To date, Cylindrospermopsis has not been found as a dominant species. Conroy et al. (2007)
reported it as < 2% total algal biomass in 2005, except during early spring. It has been seen each year around Sandusky Bay,
but not associated with the low levels of cylindrospermopsin or deoxycylindrospermopsin detected there or in other areas of the
Western basin (e.g., Maumee River, Boyer unpublished data). The highly variable morphology of this and other species (including
Microcystis, discussed above) may lead to misidentification of these cyanobacterial taxa. Non-heterocystous trichomes of
Cylindrospermopsis can be easily misidentified as an Oscillatoria (Planktothrix) and overlooked, or misidentified as Raphidiopsis
curvata, which has been identified in recent Maumee Bay samples. Strains of this species produce deoxycylindrospermopsin (e.g.,
Wilhelm and Li unpublished data, Gugger et al. 2005).
Taste-odour: Geosmin and 2-MIB are likely the cause of annual musty-muddy odour problems in drinking water supplied from the
Western basin (e.g., Toledo). In addition, significant odour is produced by extensive rotting mats of shoreline attached algae. The
planktonic cyanobacterial taxa which are currently problematic in Lake Erie (Microcystis and the local strain of Planktothrix) do
not produce these or other T&O compounds which would impair drinking water supplies (e.g., Watson et al. 2008a).
Bentbic cyanobacterial impairment is becoming a key issue in some areas. Recent severe impairments of beaches by thick mats
of the cyanobacterium Lyngbya wollei have been reported in the mouth of the Maumee River (Western basin) at sites with high
ambient P concentrations in the overlying water (Watson et al. 2008b). These have provoked significant media coverage and
website postings". The mats have not been found to produce any of the common toxins and represent no direct threat to human
health (Quilliam, Wilhelm, and Boyer unpublished data). However, they do produce significant T&O problems and foul fishing
nets, but their effects on bacterial levels on beaches and benthic foodwebs are unknown.
Other HABs taxa: In addition to the invasive cyanobacterial taxa noted above (Cylindrospermopsis, Lyngbya wollei) which produce
direct impairments, numerous other taxa have been recorded in Lake Erie (cf., Mills et al. 1993, Patterson et al. 2005). These
include invasive species (e.g., attached red algae (Bangia atropurpurea, Chroodactylon ramosum)), and diatoms (e.g., Skeletonema
potamos, S. subsalsum, Thalassiosira guillardii, T. lacustris, T. weissflogii). Western and Central basin spring-summer biomass
diatom maxima can include the invasive diatom Actinocyclus normaniif. subsalsa, which is indicative of eutrophic, polluted sites
11 e.g. http://www.westernlakeerie.org/phosphorousalgae.html;http://glhabitat.org/iiews/glnews606.html;
http://www.epa.state.oh.us/dsw/inland_lakes/Lyngbya%20wollei.pdf
NEARSHORE AREAS OF THE GREAT LAKES 2009
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that might exhibit high conductivity, elevated levels of cations (Mg++, Ca*4), fluctuating light levels and turbulent vertical mixing.
Recent high spring abundances of the filamentous diatom Aulacoseira islandica in the Western basin (e.g., Barbiero and Tuchman
2001, S. Wilhelm unpublished data) have the potential to foul fishing nets, although to date there are no known reports of this
impairment. Extensive mats of attached green algae, notably Cladophora, are increasing in abundance along shorelines.
These outbreaks are of concern for several important reasons: i) the production of noxious and potentially toxic metabolites by
these taxa (odour, toxins); ii) fouling issues (beaches, nets); iii) impacts on aesthetics, tourist industries, and real estate values;
iv) modified nutrient recycling, sequesterment or translocation (via detached material); v) their potential to act as substrates and
attachment sites for bacterial development in recreational waters and beaches; vi) their adverse effects on food web integrity; and
vii) their appearance is often unlinked with offshore nutrient levels.
Causes and controls: Past and recent work suggests that in general Lake Erie phytoplankton are P-limited (Guildford et al. 2005).
Guildford et al. observed strong seasonality in measured P deficiency during 1997, which varied among basins, but was less acute
in the Western basin. These and other authors have alWdetected short-term N-deficiency and P + N co-limitation (Wilhelm et al.
2003, Guildford et al. 2005). More recent bioassay and enrichment studies have suggested that plankton in the Eastern basin are
co-limited by Fe, N and P, but N chemistry influences current phytoplankton structure in Lake Erie (Wilhelm et al. 2003, North
etal.20Ql).
Conroy et al. (2005b) report significant differences in PO4 and NH4 turnover rates between quagga (Dreissena bugensis) and
zebra mussels (Dreissena polymorpha), with quagga mussels tending to assimilate and possibly sequester more P or direct it
more effectively to recruitment. They suggest that changes in mussel densities and distribution and increasing predominance of
quagga mussels have important implications for the nutrient turnover rates in the nearshore areas. They also attribute, like some
other authors, some of the apparent increased predominance of Microcystis to mussel activity (cf., Madenjian 1995, Vanderploeg
et al. 2001, Barbiero et al. 2006), but the mechanism of influence is much debated. They calculated that in both 1998 and 2003,
crustacean zooplankton excreted about three times more PO4 than dreissenids, highlighting the often forgotten role of zooplankton
in nutrient turnover.
Overall, the risk of cyanobacterial dominance is driven by P in most Northern temperate fresh water systems, while short-
term deficiencies and physico-chemical and foodweb processes mediate the response (e.g., Downing et al. 2001). Our current
understanding of HABs outbreaks in the Great Lakes points to nearshore areas and drainage waters as most severely affected,
and also possibly serving as sources of biota and toxins for the offshore waters. Current estimates of P-loading to the Great Lakes
are inadequate, and in many cases, do not address the growing inputs from non-point sources from the watershed and shorelines.
Recent research is also indicating that there may be several overlooked inputs from external and internal sources (e.g., Payton et
al. 2008, Lowes and Young 2008).
Lake Ontario - Status: mixed
Lake Ontario has an extensive watershed development and urban input. Blooms of cyanobacteria and related impairments (toxins,
T&O compounds) have been identified recently in some nearshore areas, notably AOCs. Circulation and exchange can result in
plumes of affected water translocated into adjacent nearshore and offshore waters (Howell 2002, Hamblin and He 2003, Rao et
al. 2003).
Toxins: Sporadic outbreaks of high MC levels have been reported in Microcystis blooms in nearshore areas (Watson et al. 2005,
Boyer 2007, Hotto et al. 2007, Watson 2007). Data collected by larger Ontario municipal water treatment plants (e.g., Toronto,
Hamilton, Deseronto) show episodes of elevated MC in raw water, but MCs are adequately removed by the treatment process.
However, a potential risk exists for less advanced removal technology by small or private users (Watson et al. 2005, unpublished
data). Spatial and temporal levels of these toxins in specific AOCs such as the Bay of Quinte, Hamilton Harbour and the Rochester
Embayments indicate periods of severe impairment of nearshore sites by windblown accumulations of toxic material, where MC
levels can reach levels in excess of 300 ug/L (Watson et al. 2003,2005). Recent surveys have indicated the widespread occurrence
of low concentrations of anatoxin-a in both nearshore and offshore sites in Lake Ontario (Boyer 2007, Yang 2007). Other toxins
(saxitoxins and cylindrospermopsin) appear to be quite rare.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Taste-odour: Studies have identified three T&O patterns over the past five years which are, in general, unrelated to chla or total
cyanobacterial biomass. In the Northwest basin, widespread T&O is caused by abrupt and severe geosmin outbreaks, which afflict
major municipal supplies between Hamilton and Cobourg in the most densely urbanized region of Canada. Late summer T&O
peaks occur with considerable interannual variation in severity. Planktonic chla and algal biomass remain very low and show much
lower variability (2-7 ug/L; 100-500 ug/L, respectively). Climate and large-scale water movement play a key role in these events
by transporting offshore pelagic T&O production by dispersed and patchy distributions of cyanobacteria (Anabaena lemmermanii)
to nearshore water treatment plant intakes. The strength of the annual downwelling and associated T&O event varies among years
with the duration and persistence of east winds (Rao et al. 2003, Watson et al. 2007, Moore and Watson 2007). In the Northeast
end of the lake (Kingston basin) and upper St. Lawrence River, T&O is produced annually by both geosmin and MIB. This affects
an extensive shoreline (200 km) and persists over a more prolonged period (September to November). Primary sources are littoral
and epiphytic cyanobacterial biofilms in nearshore areas and macrophyte beds. Midstream amounts of pelagic chla remain low.
Geosmin and MIB co-occur or peak in succession over the season, and they vary in relative and absolute abundances (Watson and
Ridal 2004, Ridal et al. 2007). The Bay of Quinte develops annual cyanobacterial blooms, with patchy mid-summer increases in
geosmin and MIB and cyanotoxins (Watson et al. 1997,2005), but shows less extensive T&O impairment than the other two more
'oligotrophic' areas. Although T&O reaches significant levels in some areas of the Bay of Quinte, the effects are localized with
little impact on municipal drinking water supplies.
Benthic algal impairment is a major concern along many nearshore areas in Lake Ontario. Dense mats of Cladophora occur along
many nearshore areas, creating issues of fouling drinking water treatment plant intakes and beaches (Higgins et al. 2008). In
early spring, detached mats of the green algae Spirogyra and other related species in areas of the Lower St. Lawrence River and
Northwest shoreline have recently been causing severe intake fouling in drinking water plants (Watson unpublished data). Severe
impairment is also manifested by benthic mats of the cyanobacteria Lyngbya cf. wollei and epiphytic colonies of Gloeotrichia
pisum, recently identified in the St. Lawrence River near the confluence of nutrient-rich tributaries (Vis et al. 2008). These
populations of Lyngbya are non-toxic but show high geosmin production, likely the source of extensive drinking water T&O
impairment in the Montreal area. Comparisons with Lyngbya populations from Maumee Bay (Lake Erie) show morphologically
similar populations, but significant differences in cell geosmin production. The greater capacity is seen in the St. Lawrence River
population.
Pressures
The cumulative effects of past and continued stressors continue to influence the response of Lake Ontario to remedial action.
For example, major shifts in nutrient pools and recycling can result in time lags, increased variability and hysteresis, and more
stringent remedial targets might be required than traditional models predict. Current and future concerns include: i) continued
introduction of invasive species, as discussed above; ii) shoreline development and expanding urbanization, which will continue
to affect point-source and non-point source loadings, timing, magnitude and bioavailability; and iii) climate change, which will
continue to have significant effects on all components of the Great Lakes, including HABs.
Warming and increased storm events may favour higher productivity and more intense and widespread noxious blooms though
such factors as:
• extended growing season
• altered patterns of runoff, circulation, mixing, resuspension and water column stability
• warmer ambient water temperatures
• changes in water levels, coastal erosion and littoral zones
altered light regimes favouring algal taxa that are tolerant to high irradiance and UV (e.g., cyanobacteria)
• extension of distribution and success of warm water and/or invasive taxa
• indirect top-down and bottom up effects on water quality, nutrient cycling, respiration, remineralization, sediment and
hypolimnetic oxygen demand, anoxia and nutrient release.
Management Implications - Concerns and recommendations
Compatibility of long term data: sampling regimes and methods
Different sampling regimes and analytical protocols (e.g., surface or integrated sampling; taxa enumeration; toxin analyses)
employed by individual studies affect data comparability and interpretation of long-term trends (Kane et al. 2005, Conroy et al.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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2005a, e.g., Table 2). The size and complexity of the Great Lakes means that many sampling regimes are inevitably sparse and
likely to miss spatial and temporal peaks in algal abundance. Annual peaks shift in timing and size as a result of natural variability,
and differences are generally greater in more impacted, eutrophic areas, e.g., Western Lake Erie and AOCs (Frost and Culver 2001,
Conroy et al. 2005a). Furthermore, basin-wide seasonal means do not resolve temporal and spatial differences in biomass and taxa,
and thus cannot identify problem areas or potential drivers.
Year
1970
1978
1978
1983-1987
1998
1996-2002
2000-2006
Boyer;/
Watson/
Richardson
Reference
Munawar and
Munawar 1976
Munawar and
Munawar 1996
Devault and
Rockwell 1986
Makarewicz 1993
Barbiero and
Tuchman 2001
Frost and Culver
2001
Boyer 2007, Watson
etal. 2008a
Sampling regime
Apr- Dec, 4-week intervals, all
basins, 25 stations
Jun-Sept; CB & EB only; 18
stations (different sites than
1970)
V
May-Nov, all basins, 9 cruises;
87 stations
spring, summer, fall; all
basins, 33 cruises, 21 stations
spring (7-9 April) summer (2-4
Aug), 20 stations
late spring-late Sept. -Oct.; all
basins; 30 - 80 stations
late spring-late Sept.-Oct.; all
basins; 30 - 80 stations
Field methods
Van Dom, 1 , 5m, mixed- layer integrated
Van Dom, 1 , 5m depth, mixed-layer integrated
Niskin; stratified: 1m, 1m above metalimnion,
thermocline, hypolimnion, bottom. Unstratified: 1m, mid
-depth, bottom-1 m.
Niskin; deep: 1, 5, 10, 20m. shallow (West B) 1m, mid-
depth, bottom-1 m
Niskin; combined 0.5m, 5 m, 10 m, lower epilimnion
integrated tube 0-[2*SD]
Van Dome / Rosette 1 m and integrated mixed layer
Table 2. Representative surveys of phytoplankton in Lake Erie and sampling regimes.
Sources: Conroy et al. (2005), Boyer (2007), Watson unpublished.
Littoral, benthic, epiphytic and meroplanktic algal populations are not addressed by most sampling programs, yet they can account
for a high proportion of algal productivity or represent seed beds where surface blooms originate. Extensive attached algal or
cyanobacterial beds have significant effects on nutrient pools and recycling. They effectively 'decouple' nutrient loading, ambient
levels, and nearshore-offshore exchange, and they influence or mask relationships between biomass and nutrient levels or other
environmental factors.
Many 'state of the lake' papers compare mean planktonic biomass and taxonomic composition among years, based on infrequent
samples taken during the spring, summer and fall seasons. Alternative measures of algal abundance are often poorly correlated
with productivity or measures of light regime. Chla continues to be a target measure for management, yet there are often poor
correlations between chla, total algal biomass and levels of impairment. Conroy et al. (2005a) pointed out the inconsistency among
seasonal means of chla and algal biomass from early surveys and those from recent surveys, which showed resurgence in biomass,
but minimum amounts of chla. The authors suggested that the use of chla in place of biomass may explain apparent contradictions
among different recent studies regarding trends in Lake Erie, some of which conclude that biomass is still at a minimum, based
on chla.
Secchi depth (SD) is widely used to estimate the depth of the euphotic zone, and it as a basis for integrated samples (e.g., Table 2)
using a constant conversion ratio between SD and photosynthetically active radiation (PAR). This relationship is functional and
simple, but SD estimates can differ significantly seasonally and spatially from PAR extinction in the water column.
Recent advances in technology have increased the number of tools available to diagnose HABs. Examples include remote sensing,
genetic probes, moored instrumentation and profilers, fluorescence-based measures, and genetic probes. All of these are extremely
useful diagnostic tools, and when combined, can provide considerable insight into HABs occurrence, species, toxicity and ecology
NEARSHORE AREAS OF THE GREAT LAKES 2009
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(Wilhelm 2008). However, researchers should understand the limitations of these tools and use them in combination with other
methodologies. Remote imaging from satellites has potential, but it measures only surface material and needs to be carefully
groundtruthed with field samples. Fluorescence-based profiling of algal assemblages is gaining widespread, often indiscriminate,
use as a measure of community structure, but this method needs careful calibration, preferentially with local biota. Comparison
among individual instruments deployed in parallel has shown wide discrepancies (Boyer, unpublished data). Fluorescence data
need to be interpreted with caution because wavelengths used to measure chromophytes and cryptophytes overlap with those
used for the diatoms, and those used for cyanobacteria overlap with colored dissolved organic matter (CDOM). At low biomass,
resolution is poor, notably between cyanobacteria and crytophytes (Boyer unpublished data, Watson and Kling unpublished data).
Impairment criteria
As noted above, current efforts to monitor algal populations target parameters that are often unrelated to levels of toxic or nuisance
impairment and/or are based on non-quantitative measures. Toxins should be systematically investigated, particularly in high
risk source waters, using regular monitoring at recreational and drinking water intake areas. Mid to late summer spatial surveys
during high risk periods should be coupled with an alert-level framework such as that developed by the World Health Organization
(Watzin et al. 2006). More effective criteria for T&O would include regular measures of the most problematic compounds (e.g.,
geosmin, MIB, isopropyl thiol, p-cyclocitral) in source waters and municipal supplies.
In the Great Lakes, considerable progress has been made in many areas towards Remedial Action Plan (RAP) goals, not the least
of which has been an increased public awareness and participation in this initiative. However, remedial efforts are addressing a
moving target. These ecosystems are under constant assault by an expanding human population and emerging threats. Advances in
our understanding of these systems have not kept pace with these changes. Remedial and management programs should frequently
revaluate the list of target goals, their acceptable levels, and progress toward them.
Nutrient levels may or may not predict toxin or odour outbreaks. Blooms appear to be local and nearshore in origin and can spread
over considerable areas, likely the combined result of growth and translocation of surface scums. The relative importance of these
different mechanisms is not well resolved. There are numerous incidental reports, media releases and websites that may inflate
these issues. Most attention is focused on surface scums, which inevitably bias sampling efforts and perceived severity. The
blooms can appear suddenly, giving the impression of rapid growth, but they could represent biomass which has been present and
developing in the water column over a preceding undefined period of time.
The effects of invasive taxa can be numerous, both via direct impairments (e.g., blooms, toxins, odour, fouling, fisheries impacts)
and indirect effects on ecosystem structure and function (e.g., food webs, nutrient pools and recycling, water quality). In addition,
therr appearance is of concern because of implications for i) vectors (predominantly ballast water) and ii) changes in the environment
which might facilitate their establishment (e.g., temperature, substrate, salinity, pollutants). Other biota, such as macrophytes, may
indirectly or directly affect the proliferation of HABs species by modifying light and nutrient levels, and/or providing substrate
for epiphyte growth. The influence of invasive species of zooplankton (e.g., Cercopagis pengoi, Bythotrephes cederstroemi) and
benthic grazers on HABs development in the Great Lakes is unknown.
Current models and sampling design
Traditional ecosystem models are sometimes derived from empirical relationships among seasonal averages for nutrients and algal
biomass. Many are applied indiscriminately, without considering their underlying assumptions and limitations (e.g., Watson et al.
2008a). In particular, the models incorporate bias from sampling protocols, maxima and minima biovolumes, surface scums, deep
layer chla maxima, and other biomass aggregations. Depth-segregated maxima are a particular consideration for cyanobacteria
populations, many of which are buoyancy-regulating or mat-forming taxa. Benthic and littoral algal communities can also be
major sources of impairment. Different nuisance algal and cyanobacterial taxa respond very differently to stressors and nutrient
loading. Many have developed different strategies to adapt to these factors. Current models do not adequately predict algal biomass
maxima, nor levels of toxins and other related impairments of concern.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Scientists and managers are faced with two different strategies when designing sampling regimes. Each has its use and limitations,
and each must meet the underlying question and management goals.
• Random sample design: This approach represents an unbiased sampling of nearshore or offshore influences and impacts.
This strategy averages out maxima, may minimize key AOCs, and is often unable to resolve impairments and trace local
causes.
• Sampling biased towards high risk, targeted areas: This approach utilizes time- and depth-resolved sampling, and
periodic extensive spatial surveys during identified high risk periods (e.g., late summer). This approach provides a better
assessment of extreme conditions, localized risk, and targets, but it may miss maxima.
Ideally, a combination of both strategies provides the best HABs assessment and monitoring framework. However, coordination
and logistics of these programs are difficult, especially among multi-agency and international partners working within the large,
highly fragmented Great Lakes basin.
Acknowledgments
Authors:
Sue B. Watson, Aquatic Ecosystem Management Research, Canada Centre for Inland Waters, National Water Research Institute,
Environment Canada, sue.watson@ec.gc.ca, http://www.nwri.ca/staff/susanwatson-e.html
Gregory L. Boyer, Director, Great Lakes Research Consortium, State University of New York, glboyer@esf.edu
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5.6 Great Lakes Nearshore and Human Health
State of the Ecosystem
The variation in statuses and trends among the Great Lakes public health indicator topics create a challenge in assigning a specific
ecosystem assessment that would accurately represent all indicators. Levels of polychlorinated biphenyls (PCBs) continue to
decrease, but still drive advisories for limiting consumption of Great Lakes sportfish. Air quality is generally improving throughout
the basin. Beach advisories, postings and closures suggest a combination of trends ranging from deterioration to improvement, and
drinking water quality status remains good (Table 1).
ID#
4175
4177
4200
4201
4202
Indicator Name
•
Drinking Water Quality
Biological Markers of Human
2009 Assessment
(Status, Trend)
SU
Ml
Lake
HU
ER ON
•
Exposure to Persistent Chemicals
Beach Advisories, Postings and Closures
Contaminants in Sport Fish
Air Quality
•
Not Assessed Good
Status
n
Fair
•
Poor
Mixed
Note: Progress Reports and some Reports from previous
us-*
CA-1*
•
-
->
9
us-*
CA--
"*
us-*
CA-«"
•
->
->
Improving
Trend
*
Unchanging
«-
Deteriorating
?
Undetermined
years have no assessment of Status or Trend
Table 1. Human Health Indicators Assessment for 2009.
Source: Adapted from U.S. EPA and Environment Canada. State of the Great Lakes 2009.
Contaminants in Sport Fish
Concentrations of organochlorine contaminants in Great Lakes sport fish are generally decreasing. However, in the United States.
PCBs still drive advisories for limiting consumption of Great Lakes sport fish. In Ontario, most of the consumption advisories are
driven by PCBs. mercury, and dioxins and furans. Toxaphene also contributes to a small proportion of consumption advisories
for sport fish from Lake Superior and Lake Huron, according to the Ontario Ministry of the Environment (OMOE). In addition
to an indicator of human health, contaminants in fish are an important indicator of contaminant levels in an aquatic ecosystem.
Contaminants that are often undetectable in water can be detected in fish because of the bioaccumulation of organohalogen
chemicals up the food chain.
Both the United States and Canada (Ontario) collect and analyze sport fish to determine contaminant concentrations to relate
those concentrations to health protection values and or to develop consumption advice to protect human health. The Great Lake.-
Fish Monitoring Program (U.S. EPA Great Lakes National Program Office (GLNPO)) and the Sport Fish Contaminant Monitoring
Program (OMOE) have been monitoring contaminant levels in Great Lakes fish for over three decades.
Consumption advice for sport fish varies throughout the Great Lakes basin depending upon the agency or government responsible
for issuing consumption advice. In the United States, the federal government does not issue consumption advice. Rather, individual
stales and tribes are responsible for this task. In Canada. OMOE is responsible for advising Canadians on the recommendet
frequency and meal size for fish consumption from sport fish collected in their waters. U.S. EPA GLNPO does collect and analyze
contaminants in sport fish fillets and compares those concentrations to the categories set by the Protocol for u Uniform
Lakes Sport Fish Consumption Advisory that was developed by the Great Lakes states.
NEARSHORE AREAS OF THE GREAT LAKES 2009
92
-------
Advised meals
per month
General
8
4
2
1
Do not eat
Sensitive*
8
4
Do not eat
Do not eat
Do not eat
i
PCBs
(ppm)
O.105
0.105-0-2TIJ
0.211-0.422
0.422-0.844
>0.844
1
Mirex
(ppm)
<0.082
0.082-0.164
0.164-0.329
0.329-0.657
>0.657
Photomirex
(ppm)
<0.015
0.015-0.031
0.031-0.061
0.061-0.122
>0.122
Toxaphene
(ppm)
<0.235
0.235-0.469
0.469-0.939
0.939-1.877
>1.877
Mercury
(ppm)
General
0.61
0.61-1.23
1.23-1.84
-
>1.84
Sensitive*
<0.26
0.26-0.52
>0.52
>0.52
>0.52
Consumption Advice
Groups
Unrestricted Consumption
2 meals/ week •
1 meal/ week
1 meal/ month
6 meals/ year
Do not eat
Concentrations
PCBs
(Ppm)
0 - 0.05
0.06-0.2
0.21-1.0
1.1 -1.9
>1.9
Hg
(PPm)
0 <= 0.05
> 0.05 <= 0.11
>0.11 <=0.22
>.22 <= 0.95
>0.95
Chlordane
(ppm)
0-0.15
0.16-0.65
0.66 - 2.82
2.82 - 5.62
>5.62
According to OMOE
data, the level of total
PCBs in lake trout has
continued to decrease
since the early 1990s. In
Lake Superior the data
demonstrate fluctuations
over time but with an
overall decline. The
most recent OMOE Table 2. Ontario Ministry of the Environment Consumption Limits for General and Sensitive
data collected m 2006 Populations that are used in the Guide to Eating Ontario Sportfish.
indicate a maximum * Women of child-bearing age and children under 15.
consumption level of Source: On*ari° Ministry of the Environment (2009).
two meals per month while GLNPO data fall into the
one meal per week category (Tables 2 and 3). OMOE
advice to sensitive populations for sport fish from
Lake Erie is for two meals per month, while GLNPO
data fall into the one meal per month category. Current
PCB concentrations in Lake Huron OMOE lake trout
allow for the safe consumption of a maximum of
two meals per month, while current GLNPO data
fall into the one meal per week consumption advice
category. Historically, the highest concentrations of
PCBs in sport fish have been found in Lake Ontario
by OMOE and in Lake Michigan by GLNPO (OMOE Table 3- Consumption limits for sensitive* populations, from the Protocol
does not collect fish in Lake Michigan). From the late *r* Unifori^ ^ Lakes Sport Fish Consumption Advisory.
tain t IQQO vnn • r»\/rr»c i iT * f T u Women of childbearmg age and children under 15.
IV/US to lyyy, rCtSS in UMUt lake trout irom LaKe Source: Great Lakes sport Fish Advisory Task Force (1993, 2001 unpublished, 2007)
Ontario exceeded the "do not eat" consumption limit.
Substantially lower concentrations have been found in the most recent samples in 2006 and 2007, and the current levels would
permit consumption of two meals per month for the general population. Current GLNPO data for PCB concentrations in sport
fish fall into the one meal per week category. GLNPO data for PCB concentrations in sport fish from Lake Michigan can be used
to discern general trends due to multiple collection sites. These data display a general decline in PCB concentrations in coho and
Chinook salmon fillets. The majority of current concentrations fall into the one meal month consumption advice category with one
site falling into the one meal per week category. The U.S. EPA website (http://www.epa.gov/fishadvisories/states.htm) provides a
link to fish consumption advisories issued by state and tribal environmental programs and departments of health for their local
waterbodies.
Mercury in sport fish is another contaminant of concern due to the detrimental effects of methylmercury on neurological function
and development. OMOE found that walleye and lake trout collected in Lake Erie demonstrate a considerable decline in mercury
levels from 0.76 ppm in 1970 to 0.14 ppm in 2006. As a result, OMOE does not have a consumption advisory for this lake.
However, GLNPO data fall into the two meals per week advice category. Similarly, in Lake Huron, mercury levels have declined
over the last few decades, falling below the first level of concentration restriction for sensitive populations in Canada. Currently,
GLNPO data fall into the one meal per week category for Lake Huron. The other lakes have also experienced declines in mercury
concentrations in fish. According to GLNPO data, Lake Michigan sport fish fall into the one meal per month category. Based upon
the most recent data available, Lake Ontario sport fish fall into the four meals per month category for OMOE fish and the one meal
per week category for GLNPO data. The OMOE has set the advisory for Lake Superior sport fish at four to eight meals per month
for sensitive populations due to consistency in mercury levels since 2000. GLNPO data fall into the two meals per week category.
Again, the U.S. EPA website (http://www.epa.gov/fishadvisories/states.htm) provides a link to mercury-driven fish consumption
advisories issued by state and tribal environmental programs and departments of health for their local waterbodies.
Since the 1970s, there have been declines in the levels of many PBT chemicals in the Great Lakes basin due to bans on the use and/
or production of harmful substances and restrictions on emissions. However, because of their ability to bioaccumulate and persist
in the environment, PBT chemicals continue to be a significant concern. Historically, PCBs have been the contaminant that most
frequently limited the consumption of Great Lakes sport fish. In some areas, dioxins/furans, toxaphene (Lake Superior) or mirex/
NEARSHORE AREAS OF THE GREAT LAKES 2009
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photomirex (Lake Ontario) have been the consumption-limiting contaminants. OMOE has found toxaphene concentrations in
Lake Superior lake trout ranging from 0.810 to 0.346 ppm between 1984 and 2006. According to these levels, consumption of up to
four meals per month is permissible. Additionally, Health Canada recently has revised downward its tolerable daily intakes (TDIs)
for PCBs and dioxins, an action which has increased the frequency of consumption restrictions caused by PCBs and dioxins/
furans, and decreased the relative frequency of consumption restrictions for toxaphene and mirex/photomirex.
Air Quality
In general, the air quality status of the Great Lakes basin is mixed, but the trends show an overall improvement in air quality.
There have been significant improvements in air quality within the Great Lakes basin. For over a decade, there has been
considerable progress in reducing urban or local pollutants, though somewhat less in recent years. Of these pollutants, ambient
concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), lead and PM10 (particulate matter with
a diameter of 10 microns or less) have all been substantially reduced since the 1990s. For example, CO and lead concentrations
have decreased well over 70% across both the United States and Canada. Emissions of these pollutants have similarly shown large
reductions, demonstrating the successes of instituting more stringent emission standards on a wide variety of sources including
fuel combustion, transportation, and other industry; as well as efforts like the U.S. EPA Acid Rain Program and the Canada-wide
Acid Rain Strategy for Post-2000.
Air toxics are also typically urban or local pollutants. Air toxics include a large number of pollutants that, based on toxicity and
likelihood of exposure, have the potential to harm human health or adverse environmental and ecological effects. The U.S. EPA
recently released the results of its National Assessment of Air Toxics (NATA) to identify and prioritize air toxics, emission source
types and locations which are of greatest potential concern in terms of contributing to population risk. From a United States'
national perspective, benzene is the most significant air toxic for which cancer risk could be estimated, contributing 25% of
the average individual cancer risk identified in this assessment. Using data from existing monitoring networks, average annual
urban concentrations of benzene have decreased 55% from 1994 to 2006. Short-term trends should be available soon as more
data becomes available from a recently established National Air Toxic Trend Site (NATTS) network. In Canada, urban benzene
concentrations have similarly decreased by 68% from 1991 to 2006. Concentrations should continue to decrease as the U.S. EPA
projects that transportation source emissions of benzene will decrease by about 60% between 1999 and 2020.
Manganese compounds are another category of air toxics of special concern in the Great Lakes region. They are emitted by
iron and steel production plants, power plants, coke ovens, and many smaller metal processing facilities.. According to the 1999
U.S. National Emissions Inventory (NEI), U.S.EPA Region 5 had the highest manganese emissions of all 10 U.S. EPA regions,
contributing 36.6% of all manganese compounds emitted nation-wide. It appears that emissions controls have in recent years had
an impact on ambient concentrations of manganese compounds as they decreased 28% between 2000 and 2006. Additional years
of data may be needed to confirm this apparent trend. Canada has also reported significant voluntary reductions of some air toxic
emissions through the Accelerated Reduction/Elimination of Toxics (ARET) program.
Regional pollutants such as ground-level ozone and fine particulates remain a concern in the Great Lakes basin, especially in
the Detroit-Windsor-Ottawa corridor, the Lake Michigan basin, and the Buffalo-Niagara area. Ground-level ozone levels may be
augmented in the region due to local onshore circulations that can trap pollutants for days below a maritime/marine inversion.
Consistently high ozone levels are found in provincial parks near Lake Huron and Lake Erie, and western Michigan is impacted
by transport across the lake from Chicago. Ozone levels in both countries have shown continued improvement since the 1990s;
however, many areas remain in nonattainment of the U.S. ozone standard or have experienced exceedences of the Canada-wide
Standards (CWS). Furthermore, Ontario seasonal means have experienced an overall increasing trend from 1980 to 2006, with
the summer and winter means increasing by about 27% and 50%, respectively. The increases in these seasonal means appear to
be largely related to reductions in NOi emissions (changing atmospheric chemistry in urban areas) and rising global background
ozone concentrations.
Fine particulates are a health concern because of their ability to penetrate deeply into the lungs compared to larger particles. In
the United States, annual average PM25 (particulate matter with a diameter of 2.5 microns or less) concentrations have declined
nationally by 14% between 2000 and 2006. Similar trends are seen for daily PM2 5 concentrations. However, there are three areas in
the Great Lakes region that are designated as non-attainment for the PM2 5 standard (Chicago-Gary-Lake County, Illinois-Indiana
metropolitan area; Detroit-Ann Arbor, Michigan metro area; and the Cleveland-Akron-Lorain, Ohio metro area). In Canada,
continuous PM.^ monitoring has only begun quite recently so there are not enough data to show any trends. However, recent data
NEARSHORE AREAS OF THE GREAT LAKES 2009
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from Ontario indicate that five of the 18 designated sites exceeded the CWS target of 30 ng/m3. Weather also plays an important
factor in the formation and emission sources of PM2 5. In colder months the greater demand for home and office heating creates
more direct emissions of PM2 5 emissions, while in warmer months, weather conditions are more conducive to PM2 5 formation in
the atmosphere. For example, in 2005, the industrial Midwest (including Wisconsin, Illinois, Indiana, Michigan, Ohio, Kentucky,
and parts of West Virginia, Pennsylvania, and New York) had a temporary increase in PM2 s concentrations, likely the result of the
colder-than-normal winter and the hotter-than-normal summer, which elevated nitrate and sulfate levels, respectively.
Beach Advisories. Posting and Closures
Health-related postings for beaches are based upon elevated levels of Escherichia coli (E. coli), or other indicator organisms, as
reported by county health departments (United States), Public Health Units (Ontario), or municipal health departments in the Great
Lakes basin. The bacteria criteria recommendations for E. coli from the U.S. EPA are a single sample maximum value of 235
colony forming units (cfu) per 100 ml. The state of Michigan, as permitted by U.S. EPA, uses 300 cfu per 100ml. For Enterococci,
another indicator bacterium, the U.S. EPA recommended criterion is a single sample maximum value of 62 bacteria per 100 ml. If
the levels of any indicator organisms exceed the recommended criteria, then swimming is either prohibited or advisories are placed
to warn beachgoers and swimmers of the possible risk.
The percentage of Great Lakes beaches open the entire season remained nearly constant in the United States between 1998 and
2007 at an average 74%. Although it should be noted that the number of reporting beaches more than doubled between 2002 and
2004, and almost doubled again between 2004 and the past two years. In Canada, the percentage of beaches open the entire season
averaged approximately 49% from 1998 to 2007. During the 2006 and 2007 seasons, the percentage of beaches posting more
than 10% of the time averaged 9% in the United States and 42% in Canada. For consistent comparison, calculations derived from
posting data are based on the months of June, July and August.
According to Great Lakes data for 2006 and 2007, the number of beach reports has increased significantly in the United States
and slightly more than in previous years for Canada. The data illustrate that conditions have improved since 2004 and 2005, but
have deteriorated in comparison to the data from 1998 to 2003. Affecting this data may be the fact that some beaches that were
not directly situated on the Great Lakes were included in the Canadian dataset prior to 2004, but were excised from the data set
in 2004. Also the United States included significantly more beach reports in this data, thus adding to trend analysis uncertainty.
The United States Great Lakes Strategy 2002 has set a goal that by 2010 all Great Lakes beaches should be swimmable, which
would require that 90% of all monitored, high priority Great Lakes beaches meet bacteria standards more than 95% of the
swimming season. Using the strategy goal as a tool for assessment, it appears that only Lake Superior and Lake Huron currently
meet the goal in the United States. For lakes Michigan, Erie and Ontario, many groups are in the process of collaborating to
identify and remediate sources in an effort to reduce beach contamination. Unfortunately, in Canadian none of the lakes satisfied
the key objective of the Great Lakes Strategy, and while there has been some deterioration, there have also been improvements
in comparison to data from 2004 and 2005. Overall, the indicator is assessed as having a mixed status and an unchanging trend.
Drinking Water Quality
The purpose of this indicator is to evaluate chemical and microbial contaminant levels, assess the potential for human exposure
to drinking water contaminants, and review the effectiveness of policies and technologies to ensure safe drinking water. In the
United States, information is drawn from Water Treatment Plants (WTPs), which produce annual Consumer Confidence/Water
Quality reports. This information is then verified and further supplemented using the Safe Drinking Water Information System
(SDWIS). For Canada, the Ontario Ministry of the Environment (OMOE) produces annual reports from the Drinking Water
Systems (DWSs) and other sources. Data for the 2007 operational year (if unavailable then for the 2006 operational year) were
collected from 43 different WTPs in the United States, and in Canada data were collected from 74 different DWSs from January to
June of 2004. It should also be noted that the United States focuses mainly on finished or treated drinking water, whereas Canada
tests both raw and treated water.
The status of drinking water in the Great Lakes basin is best assessed through the use of 10 drinking water parameters, which
include several chemical parameters, microbiological parameters, and other indicators of potential health hazard. An established
standard then regulates these parameters. The U.S. EPA defines this standard as the Maximum Contaminant Level (MCL) and
in Ontario the standard is defined as the Maximum Acceptable Concentration (MAC). Canada also has in place the Interim
Maximum Acceptable Concentration (IMAC) with the purpose of managing parameters with insufficient toxicological data or
when it is purely not feasible to establish a MAC.
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The chemical contaminants atrazine, nitrate and nitrite were assessed in the report according to the standards set by the United
States and Canada. In the Great Lakes basin, WTP levels of atrazine did not exceed the standard for finished water and no
violations were reported. The same was true of Ontario with somewhat higher levels only being detected in raw water sources.
For nitrate, detected levels never exceeded the contamination standards of either country, thus no health complications are likely
to occur. There were only two violations in the United States between January 2006 and December 2006. In the United States,
nitrite was rarely detected and where detected it was only in finished water for WTPs using rivers, small lakes or reservoirs as
source water. No violations were reported for nitrite. Ontario had no nitrite contaminant levels exceeding MAC standards and no
violations were reported.
Microbiological parameters evaluated include total coliform, E. coli, Giardia, and Cryptosporidium. In the United States, there
were two WTPs with health-based violations as well as two monitoring and reporting violations for total coliform bacteria.
Additionally, there was one monitoring and reporting violation for E. coli, but no WTPs had health based violations. Ontario did
not find the presence of E. coli in any finished water samples, however small amounts were present in raw water samples. Ontario
also detected total coliform in a few treated water samples and in many raw water samples.
Ontario adopted removal/inactivation regulations for Giardia and Cryptosporidium, but there are no data to report at this time.
Neither Giardia nor Cryptosporidium were detected in finished water supplies from any of the WTPs in the United States Great
Lakes basin, however consumer confidence and water quality reports discussed the presence of these microorganisms in the
source waters (Lake Erie, Lake Huron, Lake Michigan, Lake Ontario, and small lakes/reservoirs). The reports illustrate the
effectiveness of the WTPs at removing these microbial contaminants, but also the need for continued research on raw water in
the Great Lakes basin. At this time it is not likely that any of the aforementioned microbial contaminants will lead to any serious
health complications.
In addition to the assessment parameters of chemical and microbial contaminants, treatment techniques including turbidity,
total organic carbon (TOC) in the United States and dissolved organic carbon (DOC) in Canada, also influence the safety of
drinking water. Turbidity data in the United States are difficult to assess due to the different requirements and regulations for
WTPs depending on the source water and treatment technique implemented. There were no health violations, but there were
two monitoring and reporting violations, which occurred in June and July of 2007. In Ontario, the 2003-2004 Drinking Water
Surveillance Program (DWSP) report indicated that 78 raw water samples, many of which originated from Lake St. Clair and the
Detroit River, exceeded the aesthetic objective.
The U.S. EPA only had one monitoring and reporting violation for total organic carbon. For dissolved organic carbon, Ontario
found that there were 110 violations identified from raw water samples based on their 2003-2004 data. Most of the high DOC
results came from raw water originating from small rivers and lakes.
Pressures
Contaminants in Sport Fish
In the United States, state and tribal governments currently provide information to consumers regarding the consumption of sport-
caught fish. The guidance and advice offered by these governments are not regulatory, though some states use federal commercial
fish guidelines for the acceptable level of contaminants. Each state or tribe is responsible for the development offish consumption
advisories and tailoring the advice to meet the health needs of its citizens. As a result, advice may vary between state and tribal
programs for the same lake and species. Ontario does maintain federally regulated advice and guidelines, and the data suggest
that concentrations of PBT contaminants such as PCBs have declined in lake trout throughout the Great Lakes basin. However,
concentrations still exceed current consumption limits thereby stressing the necessity for regular monitoring. Furthermore, the
addition of chemicals of emerging concern into monitoring programs should be implemented to help stay ahead of the curve.
Air Quality
Air quality is in a complicated state as continued economic growth, population growth, and the associated urban sprawl threaten
to offset emission reductions achieved by policies currently in place. Climate change may also bring about meteorological changes
that are more conducive to increased ambient concentrations of many pollutants. There is also increasing evidence of changes to
the atmosphere as a whole. Continuing health research is also producing evidence that existing standards may need to be lowered
and that multi-pollutant effects may need to be addressed.
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Beach Advisories, Postings and Closures
Beach advisories, postings and closures all rely upon laboratory analysis of samples that may take 18 to 24 hours before processing
is completed. Due to the time lag, the efficiency of posting and later lifting restrictions is reduced. The delay in developing a rapid
test protocol for bacteriological indicators, as well as the costs, training, and collection times associated with rapid methods, is
lending support to the use of predictive models to estimate when bacterial levels may exceed water quality standards. For instance,
assuming contaminant sources remain consistent in the Great Lakes, past sample data may be used to forecast when elevated
bacterial counts may occur (such as poor recreational water quality after a specific meteorological event).
Additional point and non-point source pollution at coastal areas due to population growth and increased land use may result in
additional beach postings, particularly during wet weather conditions. In the United States, all coastal states (including those along
the Great Lakes) have criteria as protective as U.S. EPA's recommended bacteriological criteria (use of E. coli or Enterococci
indicators) applied to their coastal waters. Conditions required to post Ontario beaches as unsafe have become more standardized
due to the 1998 Beach Management Protocol, but the conditions required to remove the postings remain variable.
Drinking Water Quality
The greatest pressure to the quality of drinking water within the Great Lakes basin is degraded runoff. Several causes for a
reduction in quality include the increasing rate of industrial development on or near water bodies, low-density urban sprawl,
and agriculture (both crop and livestock operations). Point source pollution, from wastewater treatment plants for example, can
also contribute to the contamination of raw water supplies and can be considered an important pressure. Additionally, there is an
emerging set of pressures derived from newly introduced chemicals of emerging concern (i.e., Pharmaceuticals and personal care
products, endocrine disrupters, antibiotics and antibacterial agents). Invasive species might also affect water quality, but to what
extent is still unknown.
Management Implications
Contaminants in Sport Fish
Health risk communication and cooperation among national, state, and tribal governments is essential to develop and distribute the
same message regarding safe fish consumption. Currently, only PCBs, mercury and chlordane (in draft form) have uniform advisory
protocols across the United States Great Lakes basin. Additional uniform PBT advisories may be necessary in order to limit public
confusion. Increased monitoring and reduction of PBT chemicals are also needed. Furthermore, potential negative health effects
from exposure to PBT chemicals and the monitoring of contaminant levels in environmental media and bio-monitoring of human
tissues should be addressed and/or improved upon.
Air Quality
In Canada, new ambient standards for particulate matter and ozone have been endorsed, with an achievement date of 2010. New,
more protective ambient air standards for ozone and particulate matter have also been promulgated in the United States. Emission
standards and residual risk analyses will continue to be promulgated for sources of toxic air pollution in the United States under
the Clean Air Act. In December of 2000, both Canada and the United States signed the Ozone Annex to the 1991 U.S.-Canada Air
Quality Agreement (Agreement), which commits both countries to reducing emissions of NOx and VOCs. The United States and
Canada have also undertaken cooperative modeling, monitoring, and data analysis as well as developed a work plan to address
rransboundary particulate matter issues. In 2007, the two governments announced that negotiations will start on a Particulate
Annex to the Agreement. Efforts to reduce toxic pollutants will also continue under the North American Free Trade Agreement,
the Security and Prosperity Partnership, and through United Nations-Economic Commission for Europe protocols.
Beach Advisories. Postings and Closures
States provinces, and municipalities are continuing to identify point and non-point sources of pollution in recreational waters.
Potentially harmful sources include combined sewer overflows (CSOs), sanitary sewer overflows (SSOs), malfunctioning septic
systems and poor livestock management practices, which can become exacerbated after heavy rainfall. In an effort to address
these concerns in 2007 U.S EPA issued grants to nine parties to participate in a pilot beach sanitary survey project at 61 Great
Lakes beaches in the United States and Canada. The goal is to identify sources of pollution and evaluate the beaches and
surrounding watersheds. Additionally, the Great Lakes Regional Collaboration Strategy's Coastal Health Chapter laid out goals:
to achieve a 90-95% reduction in bacterial, algal and chemical contamination at all local beaches; and at the local level, individual
contamination events will occur no more than 5% of available days per bathing season. Sources of these contamination events will
be identified through standardized sanitary surveys, and remediation measures will be in place to address these events.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Ontario health units participate in beach management programs such as enhanced beach grooming, in-water and land debris clean-
up, waterfowl and gull deterrent and public campaigns to encourage proper disposal of food (City of Toronto, 2006). Also, the
Blue Flag program is becoming well-known and is an effective way of promoting clean beaches in Canada. It is an eco-label that
is internationally recognized and only awarded to beaches that achieve high standards in areas such as water quality, education,
environmental management and safety (Environmental Defense, 2008). In 2007, Ontario already had nine awarded Blue Flag
beaches, and five candidate beaches.
Drinking Water
A more standardized and extensive monitoring program is needed to address newer parameters of concern that might not be listed
by the U.S. EPA due to availability of resources or technology. Implementing a more extensive program should also successfully
demonstrate a correlation between drinking water quality and the status of the Great Lakes basin. At this time, the finished
drinking water data merely depict the efficiency of the WTPs rather than the overall water quality in the region. Source water data
need to be reviewed to properly assess the state of the ecosystem.
Acknowledgments
Author:
Shelley Cabrera, Oak Ridge Institute of Science and Education (ORISE) Research Fellow, Appointed to the U.S. Environmental
Protection Agency (U.S. EPA), Great Lakes National Program Office (GLNPO) 2008.
Contributors:
Todd Nettesheim, Environmental Protection Specialist, U.S. Environmental Protection Agency, Great Lakes National Program
Office.
Elizabeth Murphy, Environmental Scientist, U.S. Environmental Protection Agency, Great Lakes National Program Office.
Information Sources
Beach Monitoring & Notification. Beach Sanitary Surveys, www.epa.gov/waterscience/beaches/sanitarysurvey, last accessed
April 16,2009.
City of Toronto. 2006. Toronto beaches officially open for 2006.
http://wx.toronto.ca/inter/it/newsrel.nsf/0/7d9eb361438b6a7885257187004f9983?OpenDocument, last accessed 10 April, 2008.
Environmental Defense. 2008. Blue Flag Canada, www.blueflag.ca, last accessed 10 April, 2008.
Great Lakes Regional Collaboration, www.ghx.us, last accessed April 16,2009.
Great Lakes Sport Fish Advisory Task Force. 1993. Protocol for a Uniform Great Lakes Sport Fish Consumption Advisory.
http://www.health.state.mn.us/divs/eh/fish/glsprotocolcsversion.pdf
Great Lakes Sport Fish Advisory Task Force. 2001 (Unpublished). Discussion Paper for Chlordane Health Protection Value.
Great Lakes Sport Fish Advisory Task Force. 2007. A Protocol for Mercury-based Fish Consumption Advice, An addendum to the
1993 "Protocol for a Uniform Great Lakes Sport Fish Consumption Advisory".
http://dhs.wisconsin.gov/eh/fish/FishFS/2007Hg_Add_Final_05_07.pdf
Greenberg, T., Rockwell, D., and Wirick, H. 2009. Beach advisories, postings and closures, in State of the Great Lakes 2009.
May, J., Greenburg, T., and Sass, D. J. 2009. Drinking water quality, in State of the Great Lakes 2009.
Murphy, E., Fisher, J., Awad, E., and Bhavsar, S., 2009. Contaminants in sport fish, in State of the Great Lakes 2009.
Nettesheim, T., Herod, D., Conway, F., Bitzos, M., and Hall, Y. and 2009. Air quality, in State of the Great Lakes 2009.
Ontario Ministry of the Environment 2009. Guide to Eating Ontario Sport Fish, 2009-2010 Edition.
http://www.ene.gov.on.ca/en/water/fishguide/index.php, last accessed April 16,2009.
U.S. Environmental Protection Agency. 1986. Ambient Water Quality Criteria for Bacteria - 1986.
www.epa.gov/waterscience/beaches/files/1986crit.pdf
U.S. Environmental Protection Agency. 2006. Great Lakes Strategy 2002 - A Plan for the New Millennium.
www.epa.gov/greatlakes/gls/index.html, last accessed 12 August 2008.
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5.7 Type E Botulism
State of the Ecosystem
Background
Botulism is a ncuromuscular disease caused by several different strains of the bacterium, ClostHdiwn botulinum. The type E strain
is responsible for the botulism outbreaks that are currently affecting fish and large numbers of birds in the Great Lakes. Dormant
spores of this bacterium are endemic to the region and are naturally abundant in all soils and sediments, but are not always in the
vegetative state capable of producing botulism toxin. These spores are not only found in the sediments of the Great Lakes, but can
also be found in the intestinal tracts of live, healthy animals. These spores are resistant to extreme temperatures and desiccation,
and so are capable of remaining in the ecosystem for long periods of time (Domske 2003).
The botulism toxin is only produced when spores germinate and the bacterium enters the vegetative growth stage. This change
occurs in anoxic environments containing a suitable nutrient source, such as in areas with decaying plant material, favorable
temperatures, and pH levels (Brand ct ul. 19X8). Once these factors lead to the production of the toxin, it is possible for the toxin
to enter the food chain.
Animals, especially fish-eating birds, can contract botulism when they prey on other animals that harbor the toxin (CCWHC
2007). The effects of toxin poisoning include paralysis and often leads to death. Affected birds often have trouble holding up
their heads (also known as limber neck) and may drown. Affected fish will lose their equilibrium and may be found floating or
swimming erratically near the surface, which may actually attract birds to prey upon these fish. Dead fish and birds that wash
up on the beach can become sources for C. hotii/iinun growth, and shorcbirds may ingest the toxins as they feed on maggots and
carrion beetles within the decaying carcasses. Removal of dead birds (potential vectors) is important in dealing with an avian
botulism outbreak. Rehabilitation of sick birds is limited due to the large geographic areas involved, but may be possible in cases
when the birds did not ingest an acute dose of the toxin and anti-toxins and electrolytes are administered immediately, but it is
frequently unsuccessful (USGS-NWHC 2006).
Occurrence of Type E Botulism in the Great Lakes
The frequency and severity of type E botulism outbreaks have gone through cycles over the last several decades (Fig. 1), with
recent increases and expansion of affected areas and species leading to disturbing conclusions for the ecological health of the
nearshore waters. Although outbreaks have been documented in the Great Lakes region as far back as 1963 (Kaufmann and F'ay
1%4). annual die-offs of birds and fish on the shores of Lake Huron began again in 1998. in Lake Erie in 1999. and in Lake Ontario
in 2002 (CCWHC 2007). Over the past few years, botulism outbreaks have been particularly severe in Lake Michigan. Sleeping
Bear Dunes National Lakeshore experienced an extensive botulism-related waterbird die-off in 2006 that killed nearly 3,000
grebes, gulls, cormorants, loons and mergansers (personal communication with Ken Hyde, Park Biologist for Sleeping Bear Dunes
National Lakeshore (SLBE) 2007). In 2007. the Lake Michigan die-off impacted a much larger geographical area from Ludington
State Park north, including most of the Michigan beaches in the Upper Peninsula. Including the 1.135 birds killed due to botulism
at Sleeping Bear Dunes in 2007 (personal communication with Ken Hyde. SLBE 2007). the total estimates for that year reached
17,125 avian mortalities for the entire Great Lakes region (Fig. 2).
According to estimates compiled from the USGS National Wildlife Health Center's databases, a total of approximately 96,864
avian mortalities were attributed to type E botulism from 1963 through 2007 in the Great Lakes (USGS-NWHC 2008), although
the actual number of deaths is likely much higher due to monitoring and reporting inconsistencies. These outbreaks involved a
variety of species (Table 1): including species of special interest, such as lake sturgeon, loons, and endangered piping plovers. The
mortalities in recent years have the potential to cause population and species level effects, which make this an important focus for
future monitoring efforts.
Numerous state and federal agencies, universities, non-profits, and volunteer groups participate in botulism research, outbreak
monitoring, clean-up, reporting and outreach. With the geographic area of occurrence expanding in recent years, keeping up with
these tasks is increasingly difficult, as numerous jurisdictions are affected and resources are limited. Several workshops have been
held in previous years to help foster coordination in dealing with the issue. The most recent workshop in June 2008 highlighted
a series of focus areas in need of development within the research and management sectors. These included the desire for a more
formali/ed botulism task force to help facilitate future activities, such as improved web-based reporting and tracking of outbreaks.
database enhancement, development of cost-effective field-testing kits, and coordination and funding of additional research.
NEARSHORE AREAS OF THE GREAT LAKES 2009
99
-------
Year
1963
1964
1965
1966
1976
1981
1983
1998-2001
1999-2006
2002-2006
2006
2007
Figure 1. General distribution of type E botulism outbreaks, 1963 - 2007.
Highlighted areas are not drawn to scale, and are not representative of the exact areal extent of the outbreak. Areas highlighted
with oval or circular marks refer to time frames as opposed to isolated years, and are not indicative of the outbreaks' severity.
Sources: Compiled from maps developed by Thomas Cooley (Michigan DNR. Wildlife Disease Lab); Eric Obert (Pennsylvania Sea Grant); Mark Jankowski
(USGS - National Wildlife Health Center); and the Canadian Cooperative Wildlife Health Center (CCWHC).
Despite the evidence that the suspected
current ecological pathway of botulism is
heavily related to the impacts from a host of
invasive species, the exact mechanism that
transports it through the food chain has not
been scientifically documented, nor were the
causes of past historical botulism outbreaks
in the 1960s (possibly linked with alewife
die-offs. (Fay 1966)) fully understood.
Additionally, appropriate control measures
on a Great Lakes scale have not yet been
developed for either the invasive species or the
current suspected pathways. Research aimed at
better understanding, or even disrupting, the
environmental factors that lead to outbreaks is
currently in progress, but actual prevention or
mitigation may prove difficult. The ecological
balance of the nearshore waters has apparent ly
been upset to a point that allows these outbreaks
to continue, and managers will be challenged
to find the exact recipe of actions to restore a
healthy equilibrium in a natural setting.
American Black Duck
American Coot
American White Pelican
Bald Eagle
Barred Owl
Belted Kingfisher
Black-bellied Plover
Blue Jay
Bonaparte's Gull
Bufflehead
Canada Goose
Canvasback Duck
Caspian Tem
Common Goldeneye
Common Loon
Common Merganser
Common Tem
Double-crested
Cormorant
Duck, unidentified species
Great Black-backed Gull
Great Blue Heron
Greater Scaup
Grebe
Gull, unidentified species
Hawk, unidentified species
Heron, unidentified species
Herring Gull
Horned Grebe
Killdeer
Lesser Scaup
Long-Tailed Duck
Loon, unidentified species
Mallard Duck
Merganser, unidentified species
Northern Flicker
Northern Yellow-shafted Flicker
Oldsquaw Duck
Pheasant, unidentified species
Pied-Billed Grebe
Pigeon, unidentified species
Piping Plover
Red-breasted Merganser
Redhead Duck
Red-necked Grebe
Red-tailed Hawk
Red-throated Loon
Red-Winged Blackbird
Ring-billed Gull
Rock Dove
Sabine's Gull
Sanderling
Scaup, unidentified species
Scoter, unidentified species
Semipalmated Sandpiper
Sharp-Shinned Hawk
Spotted Sandpiper
White-winged Scoter
Winter Wren
Table 1. Great Lakes bird species affected by type E botulism.Represented
species are from historical, as well as present day. outbreaks. Affected fishes are
not listed here.
Source: USGS - National Wildlife Health Center, 2007. 2008.
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100 -
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1/5
0)
(U
t:
o
25,000
20,000
15,000
• National Wildlife Health Center data
Eastern Lake Ontario Colonial Waterbird Survey 2004-2007 data
25,000
c
.2
^ 10,000
-------
consumed by larger predatory fish and piscivorous water birds. The obvious signs of this nearshore outbreak are evident in the
numerous stretches of beach with dead and dying birds and fish strewn along the waters' edge.
Management Implications
The numerous fish and wildlife mortalities caused by botulism across a widening geographic region are a continuing cause for
concern. Botulism is affecting native and sensitive wildlife populations, and it has implications for the overall ecological health of
the Great Lakes. It may also impact tourism and the enjoyment of the many visitors to local beaches. Lastly, the frustration of not
being able to mitigate the outbreaks and ambiguities around the risk posed to human health are issues of concern.
Type E botulism toxin poisoning cases in humans are extremely rare, with the only documented cases of human sickness originating
hi the Great Lakes region having resulted from the consumption of cold-smoked, vacuum packed fish during the 1960s. Botulinum
toxins are heat-inactivated during cooking, thus using common safety precautions when handling fish or waterfowl and following
correct food preparation guidelines help ensure maximum safety from the toxin. With the recent outbreaks in fish and birds
becoming an increasingly public issue, there are frequent requests for official statements that specifically relate to the current
situation. Most existing safety-related documentation includes general state agency food handling and preparation guidelines,
or it refers to cases where specific fish curing and preparation methods led to production of the toxin during non-environmental
outbreak conditions in Alaska. Recent laboratory-based studies investigating botulism's effects on fish and resulting toxin levels
in their viscera and tissues have further supported the assumption that type E botulism associated with Great Lakes wildlife poses
minimal human health risks (Yule et al. 2006). However, additional laboratory and field research and definitive government health
agency statements regarding consumption of sport fish and waterfowl during an outbreak would assist in delivering a cohesive
message to the general public about their safety when questions arise.
As long as botulism outbreaks continue to occur on an annual basis, Great Lakes managers will be called upon to facilitate
coordination and support of the actions needed to understand, prevent, mitigate and respond to this problem.
Comments from the author(s)
The current historical data on botulism mortalities exists in numerous locations and with various inconsistencies. Mortality
estimates presented in this report are not meant to be interpreted as actual counts, but should serve to highlight the overall
magnitude of botulism's effects.
If the level of data quality could be improved, it would enable more rigorous data analysis projects that might begin to answer some
of the research questions at hand. Refinement of a centralized reporting mechanism and data repository could also be beneficial for
dealing with other existing wildlife diseases and those that have yet to come.
Acknowledgments
Author Chiara Zuccarino-Crowe, Oak Ridge Institute for Science and Education (ORISE) Research Fellow on appointment to
the U.S. Environmental Protection Agency (U.S. EPA), Great Lakes National Program Office (GLNPO), zuccarino-crowe.
chiara@epa.gov
Contributors:
Anne Ballmann, DVM, Ph.D., Wildlife Disease Specialist, USGS - National Wildlife Health Center
David Blehert, Ph.D., Microbiologist, USGS - National Wildlife Health Center
Murray Charlton, Environment Canada - retired
Stacey Cherwaty, Environment Canada
Helen Domske, Coastal Education Specialist, New York Sea Grant
Elizabeth Hinchey Malloy, Ph.D., Great Lakes Ecosystem Extension Specialist, Illinois-Indiana Sea Grant
Ken Hyde, Wildlife Biologist, Sleeping Bear Dunes National Lakeshore, National Park Service
Elizabeth Murphy, MPH, Great Lakes Fish Monitoring Program Manager, U.S. EPA, GLNPO
Eric Obert, Extension Director, Pennsylvania Sea Grant
James Schardt, Life Scientist, U.S. EPA, GLNPO
Information Sources
Brand, C.J., Schmitt, S.M., Duncan, R.M., and Cooley, T.M. 1988. An outbreak of Type E Botulism among common loons (Gavia
immer) in Michigan's Upper Peninsula. Journal of Wildlife Diseases 24(3): 471-476.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Breederland, M. 2008. Botulism Coordination Meeting, Feb 6, 2008 - Final Summary.
Canadian Cooperative Wildlife Health Centre (CCWHC). 2007. "Type E Botulism in Birds." October, 2007.
http://www.ccwhc.ca/wildlife_health_topics/botulism/botulisme_org.php (accessed January 2008).
CCWHC. 2008. "Ontario's 2007 Botulism Incidents." February 25, 2008.
http://www.ccwhc.ca/en/botulism_ontario_news.php (accessed September 2008).
Domske, H. 2003. Botulism in Lakes Erie 2003 Workshop Proceedings. New York Sea Grant, Ohio Sea Grant and Pennsylvania
Sea Grant. http://seagrant.psu.edu/publications/proceedings/Botulism(2003).pdf
Domske, H. 2004a. Botulism Update. New York Sea Grant.
http://www.seagrant.sunysb.edu/botulism/pdfs/botulism-updateSu04.pdf
Domske, H. 2004b. Botulism in Lakes Erie 2004 Workshop Proceedings. New York Sea Grant, Ohio Sea Grant and Pennsylvania
Sea Grant. http://www.seagrant.sunysb.edu/botulism/pdfs/Botulism-Proc04.pdf
Fay, L.D. 1966. Type E botulism in Great Lakes water-birds. Michigan Department of Conservation, Research and Development
Report No. 54. March 3, 1966. Rose Lake Wildlife Research Center, East Lansing, MI. Presented at the 31st North American
Wildlife and Natural Resources Conference, March 14, 1966.
Getchell, R.G., and Bowser, P.R. 2006. Ecology of Type E Botulism within Dreissenid Mussel Beds. Aquatic Invaders 17(2): 1-8.
Great Lakes Sea Grant Network and U.S. EPA. 2007. Botulism in the Great Lakes - Frequently Asked Questions.
http://www.miseagrant.umich.edu/habitat/avian-botulism-faq.html
Hecky, R.E., Smith, R.E.H., Barton, D.R., Guildford, S.J., Taylor, W.D., Charlton, M.N., and Howell, T. 2004. The near shore
phosphorus shunt: a consequence of ecosystem engineering by dreisseneids in the Laurentian Great Lakes. Canadian Journal
of Fisheries and Aquatic Sciences 61(7):2185-1293.
Kaufmann, O.W., and Fay, L.D. 1964. Clostridium botulinum type E toxin in tissues of dead loons and gulls. Michigan State
University Agricultural Experiment Station Quarterly Bulletin 47(2):236-242.
Ludwig, J.P., and Bromley, D.D. 1988. Observations on the 1965 and 1966 Mortalities of Alewives and Ring-Billed Gulls in the
Sag'inaw Bay - Lake Huron Ecosystem. The Jack-Pine Warbler, March 1988, 66(1).
Mortality figures for 2004-2007 in Eastern Lake Ontario from Laird Schutt and Chip Weseloh, unpublished data from Colonial
Nesting Waterbird Surveys. Estimates supplied via personal communication with Chip Weseloh, 2008.
Mortality figures thru 2006 from internal databases maintained by the USGS - National Wildlife Health Center. Estimated totals
compiled in February, 2007.
Mortality figures for 2007 compiled through the coordination of USGS - National Wildlife Health Center. Estimated totals supplied
via personal communication with Mark Jankowski, February 2008 and Nathan Ramsay, March 2008. ^
New York State Department of Environmental Conservation. "Type E Botulism in Lakes Erie and Ontario."
http://www.dec.ny.gov/animals/28433.html (accessed December 2006).
Pennsylvania Sea Grant and Penn State Erie. 2003. Botulism Factsheet:
httpV/www.pserie.psu.edu/seagrant/publications/fs/Botulism_12-2003.pdf.
Sleeping Bear Dunes mortality estimates supplied via personal communication with Ken Hyde, Sleeping Bear Dunes National
Lakeshore, March 2007 and December 2007. http://www.nps.gov/slbe/ n n D AC nn*
U.S. EPA. 2008. Great Lakes Basinwide Botulism Coordination Workshop Proceedings, June 24-25,2008. EPA 950-R-08-OU5.
http://glrc.us/documents/botulism/GLBotCoordWorkshopJune2008.pdf
USGS National Wildlife Health Center. Disease Information, "Avian Botulism," 7 November 2006.
http-//wwwnwhc usgs.gov/disease_information/avian_botulism/index.jsp (accessed December 2006).
Yule A M Austin, J.W., Barker, I., Cadieux, B, and Moccia, R.D. 2006. Persistence of Clostridium botulinum Neurotoxii,i Type, E
in Tissues from Selected Freshwater Fish Species: Implications to Public Health. Journal of Food Protection 69(5): 1164-1167.
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5.8 Nearshore Habitats of the Great Lakes
"I1
State of the Ecosystem
Anthropogenic activities have dramatically altered the Great Lakes basin through agricultural practices, urban development.
industrial and commercial activities, and introduction of non-native species (Christie t-t ul. 1987. Steedman and Regier 1987.
Edsall 1996). These activities have altered the natural physical and ecological processes throughout the basin (Regier and Hartman
1973. Steedman and Regier 1987). The nearshore zone, in particular, has been heavily impacted by chemical pollution, nutrient
enrichment, and physical alterations resulting from intense industrialization and urbanization (Krieger el al. 1992). The resulting
habitat degradation is of great concern because Great Lakes littoral areas have high rish diversity and are important to the life
histories of most native Great Lakes fishes (Goodyear el al. 1982. Lane et al. 1996a. b. Brazner 1997). Coastal margin and
nearshore areas also have diverse wetland, benthic. and planktonic communities that comprise the lower portion of food web.
These organisms provide other important ecosystem services as well.
(Climate)
Energy
Substrate
(Geology)
Habitat
Water Mass
(Hydrology)
• Energy - estimated from hydraulic calculations
for both oscillatory and unidirectional flows.
• Substrate - bedrock, composition, texture,
hardness, stability, porosity, permeability,
roughness.
• Water Mass - depth, temperature, turbidity,
nutrients, contaminants, and dissolved
oxygen.
• Habitat - physical characteristics and energy
conditions that meet the needs of a specific
species and/or biological community for a
given life stage.
Figure 1. Fundamental characteristics of aquatic habitat.
The "sweet spot" is where energy, substrate, and water mass characteristics all meet the needs of an organism for a
given life stage, i.e. "habitat".
Source: Mackey (2005).
The pattern and distribution of Great Lakes nearshore habitats are controlled, in part, by the underlying physical characteristics of
the basin and interactions between energy, water, and the landscape (e.g.. Sly and Busch 1992. Higgins ct al. 1998. Mackey 2005).
Coastal margin and nearshore aquatic habitats are three-dimensional and dynamic. Aquatic habitats are defined by a range of
physical characteristics and energy conditions that can be delineated geographically and meet the needs of a single species.
biological community, or ecological function related to life stage (Fig. 1). To be utilized as habitat, these physical characteristics
and energy conditions must exhibit an organizational pattern, persist, and be "repeatable" - elements that are essential to maintain
a sustainable and renewable resource (Peters and Cross 1992).
Within the Great Lakes, individual species, biological communities, and the ecosystem have adapted to and utilized the natural
range of available habitats, including seasonal patterns and movement of water, energy, and materials through the system (e.g.
Busch and Lary 1946. Jones ct ul. 1996). Moreover, coastal and nearshore habitats are created and maintained by interaction
between coastal landscapes, water-lex el regimes, open-lake circulation processes and patterns, nearshore coastal processes, and
the pathways and connections along which these processes act. Nearshore coastal processes include oscillatory and unidirectional
flows generated by \\a\es and currents. These factors control the distribution of materials and substrates in coastal margin and
nearshore zones (areas encompassed by water depths generally less than 15 m) and also regulate the ecological utilization of
energy, materials, and water as it is conveyed through these shallow-water systems.
NEARSHORE AREAS OF THE GREAT LAKES 2009
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Pressures
The habitat requirements for fish are highly variable and depend on the species and life stage of the organism. Benthic communities
are highly dependent on substrate type and stability. For example, underwater video data show that complex habitat structure
(rugosity) and areas with bathymetric relief are preferred habitats that attract a diverse range offish species. Many species require
relatively shallow, well-oxygenated waters flowing though coarse gravel and cobble substrates with protective interstitial spaces.
In many cases, spawning areas are adjacent to nearshore nursery areas and rely on regional circulation patterns to transport larval
fish into adjacent nursery areas. However, anthropogenic actions along the shoreline and in coastal watersheds have affected
coastal and nearshore processes, pathways, and connections.
For example, anthropogenic alterations to river mouths and the "armoring" of shorelines modify flow paths and disrupt nearshore
coastal processes that create and maintain coastal margin and nearshore habitats. Reductions in the volume of available littoral sand
has lead to the "coarsening" of nearshore substrates and the gradual replacement of mobile sand sheets with stable heterogeneous
lag deposits resting on bedrock or cohesive clay substrates (Fig. 2). The loss of protective sand sheets has significantly altered
the pattern and distribution of nearshore aquatic habitats and has created ideal conditions for colonization by dreissenids. round
gobies, and other non-native species that use coarse-grained substrates as habitat. Non-native species have altered the physical,
chemical, and biological characteristics of historical spawning sites as well. Colonization by dreissenids has reduced or eliminated
interstitial spaces (potential spawning habitat) in many coarse-grained substrates.
However, coarse-grained substrates show little evidence for active erosion and or recent disturbance (Mackey unpublished data).
These deposits are heavily coloni/ed by dreissenids and Chuloplxmi and form an armored pavement on the lakebed. Moreover.
exposed cohesive clay deposits have been observed on the lakebed in approximately two-thirds of the nearshore sites surveyed.
Multiple sites had cohesive clay deposits exposed on the lakebed either as flat eroded surfaces or elongate clay ridges and swales.
These clay ridges ranee from (1.5 to 2 m in height from the lakebed with rippled coarse-grained sand and dreissenid shell fragments
in the adjacent swales. Field observations and underwater video from multiple sites show that cohesive clay deposits are not
colonized by dreissenids or Clti(h>f>ht»\i (Fig. 3). When cohesive clays are exposed on the lakebed. the surface of the cohesive
clays starts to soften creating smooth slick surface that ablates v cry slowly during turbulent flow events (storms). The ablating clay
surface prevents attachment ot dreissenid bissle threads and if they do attach, they are swept clean by turbulent flows during the
next storm event. Adjacent coarse-grained lag deposits (boulders, cobbles, gravel) are extensively colonized by dreissenids and
Cladophora indicating that suitable hard substrates will be colonized at these locations Kioforth «-/ al. 2008).
Recent nearshore habitat assessments and mapping work performed in Lake Michigan and in Lake Erie suggest that many of the
substrate and habitat changes are not new and are the long-term result of actions taken many decades earlier. In other
words, with respect to nearshore coastal processes, we have passed through several major habitat "tipping" points decades ago and
are now attempting to manage the remaining habitat in severely degraded systems.
Homogeneous Mobile Sand Substrate
Heterogeneous Stable Lag Substrate
Figure 2. Underwater video images from Lake Michigan contrasting historic mobile sand substrate (left) with current stab
T of lag substrate by dreissenids and Cladophora. Wind Point survey site north of Racine, Wl. 7 m,
October 2005.
Source: Courtesy of Habitat Solutions NA. 2005.
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Figure 3. Underwater video image of cohesive clay ridge (light blocky
material) surrounded by medium to coarse sand and large cobbles/
small boulders.
Dreissenids colonize the hard boulder cobble substrates, but do not
colonize the ablating cohesive clay deposits. Chiwaukee survey site
south of Kenosha, Wl. 8 m, October 2005.
Source: Courtesy of Habitat Solutions NA. 2005.
Moreover, land cover changes in watersheds have
altered flow paths to tributaries, changing flow
regimes and dramatically increasing sediment and
nutrient loads, causing channel erosion and instability.
and degrading the quality of tributary flows into the
Great Lakes. Tributary waters must flow through
coastal margin and nearshore habitats to reach the
open lake, and are therefore affected by anthropogenic
actions in the watersheds. Chemical contaminants,
nutrients, and fine-grained sediments have adversely
affected nearshore habitat structure and ecosystem
function. Even though steps have been taken to slow
the rate of degradation, continued population growth
and associated changes in land cover in Great Lakes
watershed will continue cause further degradation of
coastal margin and nearshore habitats.
Through climate variability and/or artificial flow-
management, lower lake water levels may change
open-lake circulation patterns and connectivity; alter
open-lake thermal structure; affect nearshore coastal
processes; and reduce hydraulic connectivity between
coastal margin wetland/barrier systems and the
Lakes. Continued coastal development pressures and
submerged lands ownership issues do not bode well for natural ecosystem adjustments to long-term changes in Great Lakes water
levels.
Management Implications
The trend towards habitat degradation is expected to continue, necessitating the implementation of enlightened management
strategies to ensure the future sustainability of remaining nearshore habitats critical to maintaining native biodiversity. Ecological
integrity is achieved by protecting and restoring water level regimes, nearshore coastal processes, and flow paths and connections
that structure, organize, and regulate coastal margin systems and create regional-scale patterns that link coastal margin and
open-lake areas within the basin.
Acknowledgments
Author: Scudder D. Mackey, Ph.D. Habitat Solutions NA, scudder@sdmackey.com
Information Sources
Brazner. J. C. 1997. Regional, habitat, and human development influences of coastal wetland and beach fish assemblages in Green
Bay, Lake Michigan. Journal of Great Lakes Research 23(1):36-51.
Busch, W.D.N.. and Lary. S.J. 1996. Assessment of habitat impairments impacting the aquatic resources of Lake Ontario. Canadian
Journal of Fisheries and Aquaric Sciences 53 (Suppl. 1): 113-120.
Christie. W. J., Collins, J. J. G., Eck, W., Goddard, C. I.. Hoenig, J.M., Holey, M., Jacobson, L.D., MacCallum, W., Nepszy, S.J.,
O'Gorman. R... and Selgeby. J. 1987. Meeting future information needs for Great Lakes fisheries management. Canadian
Journal of Fisheries and Aquatic Science 44 (Suppl. 2): 439-447.
Edsall, T.A. 1996. Great Lakes and Midwest region. In: Status and trends of regional resources, eds. M.J. Mac. G.S. Farris, P.A.
Opler. P.O. Doran. and C.E. Puckett. National Biological Service, Washington, DC.
Goforth. R.R., Mackey, S.D.. and Sloan, J.S. 2008. Nearshore habitat and biological community mapping in Western Lake
Michigan: Final Report March 2008. National Fish and Wildlife Foundation. U.S. EPA, pp. 40 with appendices.
Goodyear. C.D., Edsall, T.A., Ormsby-Dempsey, D.M., Moss. G.D., and Polanski, P.E. 1982. Atlas of spawning and nursery areas
of Great Lakes fishes. USFWS, Report FWS/OBS-82/52. Volumes 1-14. Washington. DC.
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Higgins, J., Lammert, M., Bryer, M., DePhilip, M., and Grossman, D. 1998. Freshwater conservation in the Great Lakes basin:
development and application of an aquatic community classification framework. Chicago, Illinois: The Nature Conservancy,
Great Lakes Program.
Jones, M.L., Randall, R.G., Hayes, D., Dunlop, W., Imhof, J., Lacroix, G., and Ward, N.J.R. 1996. Assessing the ecological effects
of habitat change: moving beyond productive capacity. Canadian Journal of Fisheries and Aquatic Sciences 53 (Suppl. 1):
446-457.
Krieger, K.A., Klarer, D.M., Heath, R.T., and Herdendorf, C.E. 1992. A call for research on Great Lakes coastal wetlands. Journal
of Great Lakes Research 18: 525-528.
Lane, J.A., Portt, C.B., and Minns, C.K. 1996a. Nursery habitat characteristics of Great Lakes fishes. Canadian Manuscript Report
of Fisheries and Aquatic Sciences 2338.
Lane, J.A., Portt, C.B., and Minns, C.K. 1996b. Habitat characteristics of adult fishes of the Great Lakes. Canadian Manuscript
Report of Fisheries and Aquatic Sciences.
Mackey, S.D. 2005. Physical Integrity of the Great Lakes: Opportunities for Ecosystem Restoration. Report to the Great Lakes
Water Quality Board, International Joint Commission, Windsor, ON.
Peters, D.S., and Cross, F.A. 1992. What is coastal fish habitat? Pages 17-22 In Richard H. Stroud (ed.), Stemming the tide of
coastal fish habitat loss. Proc. of a Symposium on Conservation of Coastal Fish Habitat, Baltimore, MD. Published by the
National Coalition for Marine Conservation, Inc., Savannah, GA.
Regier, H.A., and Hartman, W.L. 1973. Lake Erie's fish community: 150 years of cultural stresses. Science 180: 1248-1255.
Sly, P.O., and Busch, W.D.N. 1992. Introduction to the process, procedure, and concepts used in the development of an aquatic
habitat classification system for lakes. In: The Development of an Aquatic Habitat Classification System for Lakes, eds.
W.D.N. Busch and P.G. Sly. CRC Press. Boca Raton, Florida: 1-13.
Steedman, R.J., and Regier, H.A. 1987. Ecosystem science for the Great Lakes: perspectives on degradative and rehabilitative
transformations. Canadian Journal of Fisheries and Aquatic Sciences 44 (Suppl. 2): 95-103.
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5.9 Nearshore Physical Processes
State of the Ecosystem
Introduction
Physical characteristics and natural processes structure, organize, and define aquatic ecosystems and regulate the biological and
chemical elements of the system (Pof'tV/ al. 1997. Richter ct at. 199S. Richter and Richter 2000. Baron el al. 2003, Ciruna 2004).
The nearshorc physical processes of the Great Lakes are much more similar to marine coastal systems rather than the shallow
inland lake systems which are commonly used as analogues to the Great Lakes (Mackey and Goforth 2005). These similarities and
differences are primarily due to size, scaling, and energy issues. The Great Lakes are sizeable bodies of water with the potential
to rival many marine systems with respect to wave energy and ability to erode and transport geologic materials along the coast.
The physical integrity of the nearshore is based on the idea (hat sustainable nearshore waters and ecosystems require protection and
restoration of nearshore processes, pathways, and landscapes - the three fundamental components of physical integrity (Mackey
2005). Unlike traditional approaches that historically have relied upon the ongoing measurement and monitoring of site-based
system components through time. & process-based approach considers changes in coastal processes due to altered pathways and
landscapes in the coastal margin and nearshore areas.
Even though the impact of shoreline modifications on coastal processes has been known for many decades, the impact of altered
coastal processes on nearshore habitat structure, coastal ecosystems, and nearshore water quality is not generally understood. This
chapter will briefly explore the concept of physical integrity within coastal margin and nearshore waters and summarize how these
concepts can be applied to assess regional changes in habitat structure and impacts on coastal ecosystems.
Nearshore Landscapes. Processes, and Pathways
Landscapes include and are defined by the integrated components of land and water area (i.e. geology, geomorphology. and
land cover) upon which natural processes act within the Great Lakes basin (Mackey 2005). The most commonly used subunit
of landscapes is watersheds. Watersheds are defined by surface and/or groundwater hydrology and represent the surface area
that collects and channels water into tributaries that flow into a common main stem or channel. Even though landscapes and
watersheds arc typically considered to represent areas with some regional extent, the terms are applicable at multiple scales,
Terrestrial watersheds are linked to the Great Lakes via hydrology, i.e. the movement of surface or groundwater across and through
the landscape along flow paths (pathways) into a Great Lake. The flow paths are controlled by watershed components, generally
surface relief and the composition (permeability) of underlying geologic materials within the watershed.
With respect to nearshore systems, coastal margin and nearshore landscape components include river mouths and coastal wetlands;
beaches, dunes, and coastal margin swash zones; coastal morphology and composition (cohesive clay bluffs, bedrock, clay banks.
thin sand barriers); available sediment supply; nearshore water depths and slope; and shoreline orientation (exposure to wave-
energy). All of these coastal landscape components are created, maintained, and connected by the interaction of nearshore coastal
processes with the landscape (Mackey 2005).
Pathways are defined as the paths along which natural coastal processes act to convey energy, water, and materials through the
nearshore system (Mackey 2005). Implied in this definition arc: 1) functional pathways, which include functional and physical
connections between physical components of the system that include how energy is distributed within a system, and 2) Irydrologic
pathways, which include flow paths, hydraulic connectivity, and how water, materials, and energy move through the system.
Within nearshore systems, the primary transport mechanisms are linked to the open-lake and are driven by regional flow, wave,
or storm-driven processes that transport water, materials, and energy into, through, and out of coastal margin and nearshore areas.
The pathways along which coastal waters move arc defined by littoral cells, i.e. reaches of coastline where water and sediments are
transported laterally along the shoreline by the energy of waves breaking on the beach. The direction of movement is influenced
by prevailing winds and or the magnitude and frequency of storms and waves impinging on the shoreline.
These littoral cells may span nearshore areas adjacent to several terrestrial watersheds and may or may not be connected to or
influenced by these terrestrial watersheds. Even though there are spatial "zones of influence" where tributary outflows may affect
nearshore coastal processes for limited periods of time, these zones of influence are highly dynamic and may extend laterally
across multiple watershed boundaries. The dynamic nature of these nearshore pathways and variability in coastal transport
processes make any meaningful linkages between watersheds and coastal margin, nearshore areas exceedingly difficult. In most
cases, traditional watershed paradigms can not be applied to nearshore coastal systems.
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Below are descriptions of the hydrogeomorphic processes that may directly (or indirectly) influence coastal margin and nearshore
areas of the Great Lakes. Coastal margin and nearshore processes dominate, but locally other processes may also influence the
coastal margin and nearshore zones. Table 1 summarizes the attributes, pathways/area, and connectivity of these hydrogeomorphic
processes.
Fluvial processes - Processes associated with channelized flow. These processes and flows are highly dynamic; may
be spatially and temporally episodic; are generally unidirectional (down slope); and act within or along linear stream
corridors and/or drainage networks within watersheds. Fluvial processes are highly dependent upon lateral hydraulic
connectivity with adjacent floodplain and watershed surfaces, and longitudinal down-slope hydraulic continuity and
connectivity within stream channels.
Groundwater processes - Processes associated with infiltration and groundwater flow - hydraulic continuity. These
processes and flows may be dynamic; spatially and temporally episodic; unidirectional and/or bidirectional; and may act
across broad landscape surfaces and/or within stream channels or lakes. Groundwater processes are highly dependent on
potentiometric surface (water table elevation), surficial geology and soils (aquifers), hydraulic continuity (groundwater-
surface water connections), and recharge area.
• Coastal margin and nearshore processes - Processes associated with wave and storm-generated currents and flows,
except where influenced by fluvial processes and flows near river mouths. These processes and flows are highly dynamic,
spatially and temporally variable and episodic, may be oscillatory (bidirectional) or unidirectional, are water-depth
dependent; and generally act parallel to shore with a seasonal onshore-offshore component. Coastal margin and nearshore
processes are highly dependent on shore-parallel hydraulic connectivity (littoral processes) and shore-normal hydraulic
connectivity (deltaic, estuarine, wetland, barrier-dune hydraulic connectivity).
• Open-lake processes - Processes associated with wave and storm-generated currents and flows, superimposed over
broad-scale hydraulic (riverine) or thermally driven (seasonal) flows. These processes and flows are dynamic, spatially
and temporally variable and episodic, may be oscillatory (bidirectional) or broad-scale unidirectional flows, and act
within and between lake sub-basins, major connecting and tributary channel inflow and outflow points. Broad-scale
regional unidirectional flows act within and between lake sub-basins and major connecting and tributary channel inflow
and outflow points. Open-lake processes are highly dependent on lateral hydraulic connectivity between adjacent water
masses and major connecting and tributary channel inflows and outflows.
Ecological benefits of water are related to the spatial and temporal pathways within the landscape and the type and severity of
impairments. The path that water takes across, or through, the landscape allows biological communities to utilize energy and
materials as water moves through the system. There is a time-distance relationship between water and the benefits that water
provides to the ecosystem. In general, as flow path complexity increases so do the ecological benefits. Constrained by existing
impairments, the ecological value of a gallon of water varies as a function of its location and residence time on, or within, the
landscape. Factors that control the time that water stays within the system are: flow velocity, path length (direction and distance
traveled), and connections between landscape components. The importance of these factors is clearly demonstrated in riverine
systems by the work by Poff et al. (1997) and subsequent work by Richter et al. (1998), Richter and Richter (2000), Baron et al.
(2003), and others.
Similarly, in nearshore systems, the coastal processes that move water and nutrients along shore provide ecological benefits and
create habitat structure. Additional complexity is introduced due to water exchanges between watersheds (river mouths), coastal
margin environments (wetlands and embayments), and the open lake. The nearshore zone is the conduit through which those
exchanges occur. Changes in Great Lakes water levels can directly affect where and how these water exchanges occur. Moreover,
anthropogenic disruptions to nearshore coastal processes may directly impact these pathways and affect Great Lakes coastal and
nearshore ecosystems.
Pressures
Landscape stressors create hydrologic impairments by altering flow characteristics and/or the functional connections and pathways
between fundamental components within the system. Within the Great Lakes, all of the natural processes listed in Table 1 act
along pathways or within hydrogeomorphic areas that have been impaired by anthropogenic activity. These impairments affect
not only the ability of natural processes to convey energy, water, materials, and biota, but alter the benefits that water provides to
the ecosystem as well. Physical modifications of the shoreline, altered water levels and flow regimes, and loss of littoral sediment
supplies and hydraulic connectivity have changed the hydrologic interactions between watersheds, coastal margin and nearshore
zones, and waters of the open lake.
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Natural Process
Attributes
Pathways/Area
Connectivity
Fluvial Processes
• Channelized flow
• Highly dynamic
• Spatially and temporally
variable and episodic
Generally unidirectional
(down slope) flow
Acts within or along linear
stream corridors and/or
drainage networks within
watersheds
Lateral hydraulic connectivity
with adjacent floodplain and
watershed surfaces
Longitudinal hydraulic
down-slope continuity and
connectivity within stream
channels
Groundwater
• Infiltration and
groundwater flow
• Highly dynamic
• Spatially and temporally
variable and episodic
Unidirectional and/
or bidirectional flows
Act across broad landscape
surfaces and/or within
stream channels or lakes
Hydraulic continuity
(groundwater-surface
water connections)
and recharge area
Potentiometric surface (water
table elevation) — surficial
geology and soils (aquifers)
Coastal Margin
and Wears/iore
Wave and storm-generated
currents and flows
Intermittent fluvial influence
near river mouths
Highly dynamic
Spatially and temporally
variable and episodic
Oscillatory bidirectional
and/or unidirectional flows
Act within or along both
shore-parallel and shore-
normal linear corridors
with seasonal onshore-
offshore components
Water-depth dependent
• Shore-parallel hydraulic
connectivity (littoral
processes)
• Shore-normal hydraulic
connectivity (deltaic,
estuarine, wetland,
barrier connectivity)
Open Lake
Wave and storm-generated
currents and flows
Superimposed over broad-
scale hydraulic (riverine) or
thermally driven (seasonal)
flows
Spatially and temporally
variable and episodic
Oscillatory bidirectional
and/or unidirectional flows
Broad-scale regional
unidirectional flows
Act within and between
lake sub-basins, major
connecting and tributary
channel inflows and outflows
Lateral hydraulic connectivity
with adjacent water masses
Hydraulic connectivity
with major connecting and
tributary channel inflows and
outflows
Table 1. Physical Processes that affect Nearshore and Coastal Margin Zones.
Source: Mackey (2005).
The single most important anthropogenic factor disrupting nearshore coastal processes and pathways is increasing
shoreline development and the physical alteration of the land-water interface. These changes fundamentally change the
coastal processes and pathways along which those coastal processes operate. These changes impact not only local areas, but have
cumulative regional impacts as well.
In shallow-water nearshore areas, nearshore sand and beach deposits are in fact part of the same littoral system and historically,
thick sand deposits extended hundreds of meters offshore. As we have continued to develop and armor our shorelines, the amount
of sediment available to keep our beaches supplied with sediment has been decreasing as shoreline armoring increases. Most of
the sand-sized sediments that make up Great Lakes beaches are derived from direct erosion of coastal bluffs, which comprises
approximately 90% of the total volume of littoral sediments along many Great Lakes coastlines (e.g. Bolsenga and Herdendorf
1993, Mackey 1995).
Coastal margin and nearshore zones are dynamic high-energy environments and sand is continually transported in a downdrift
direction by waves and littoral currents. Without a continual supply of sand, beaches (and associated nearshore sand deposits)
become progressively thinner and narrower through time. The loss of these sediments increases nearshore water depths thereby
increasing available wave energy. Eventually, the sand deposit becomes thin enough that the entire deposit is mobilized during
periods of significant wave activity, which accelerates the irreversible lakebed downcutting process.
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Similar effects can be observed adjacent to large harbor structures. In these cases, large harbor structures extend well out into the
nearshore zone disrupting natural littoral transport processes. As sand accumulates on the updrift side of the structures, beaches
become wider and water depths become shallower. Downdrift of the structure, beaches become narrower and disappear, and water
depths become deeper due to a loss of beaches and lakebed downcutting. The loss of sand due to shoreline armoring and/or large
harbor structures results in coarse-grained lag deposits and increased substrate heterogeneity in the nearshore zone. These changes
have created excellent habitat for lithophyllic invasive species (dreissenids and round gobies).
Impacts to local littoral sediment sources may also influence nearshore sand distributions. For example, the construction of dams
on many Great Lakes tributaries has trapped significant quantities of coarse-grained sediment in the pools behind those dams. The
entrapment of coarse-grained sediment by dams has reduced the available sediment supply river mouths. Moreover, most large
river mouths are heavily altered by shore protection and/or bulkheads to facilitate shipping. These areas are also dredged on a
regular basis to maintain navigable waterways.
Channel alterations due to dredging may alter tributary (river mouth), coastal margin, nearshore, and open-lake flow
patterns and connectivity. Associated with armoring of river mouths, recent reductions in Great Lakes water levels have led to
an increase in dredging activity in shallow-water nearshore areas. Not only do these dredged materials need to be disposed of,
but the widening and/or deepening of navigation channels (particularly in river mouths) may significantly alter the flow regimes
and pathways that transport water and materials into the Great Lakes. Channel modifications and bank hardening may have a
significant detrimental effect on coastal margin, nearshore, and open-lake circulation, flow patterns, and hydraulic connectivity.
Loss of protective nearshore sediment supplies has resulted in erosion and resuspension of fine-grained cohesive sediments,
thereby increasing turbidity and reducing nearshore water quality. This is particularly evident during major storm or wind
events when large waves mobilize thin sand and gravel deposits that scour and erode the underlying cohesive clays. It is not
uncommon to see turbid waters in the nearshore zone during major wind events, even though tributary loadings are minimal. The
processes and mechanisms of nearshore lakebed downcutting are clearly described in Part III Chapter 5 of the Coastal Engineering
Manual (Nairn and Willis 2002).
In riverine (fluvial) systems, altered flow regimes may cause increased bank and channel erosion, especially during major
precipitation events, thereby increasing tributary sediment loads. Locally, these suspended sediments could have short-term
detrimental impacts on coastal margin and nearshore areas by increasing turbidity, reducing water clarity, and potentially
introducing harmful contaminants into the water column.
Currently, the cumulative impacts of altered flow regimes on the Great Lakes ecosystem are unknown, primarily because we
have only started to consider the question. Existing data sets are inadequate to perform the assessment in a meaningful way (GLC
2003). Over the long term, altered flow regimes, diversions, and consumptive losses may lower water levels, thus changing open-
lake circulation patterns and connectivity, nearshore coastal processes, and connectivity between coastal margin and wetland/
barrier systems within the Great Lakes.
Management Implications
Within the context of physical integrity, sustainable natural processes are created when energy, water, and materials are conveyed
through a system in ways that correspond to undisturbed natural conditions, maintain system integrity, and promote system
resiliency and regeneration - irrespective of natural and anthropogenic perturbations. The importance of physical integrity to
protection and restoration efforts cannot be overemphasized.
Current coastal margin and nearshore management paradigms focus on individual system components and do not consider
impairments to the processes or pathways that connect and functionally link those components together. This is the main reason
why local, state, provincial, and federal agencies have been singularly unsuccessful in managing coastal margin and nearshore
habitats in any meaningful way. Moreover, most coastal regulatory programs are applied on a site-by-site basis (one property at a
time) without due consideration of the long-term cumulative impacts on coastal margin or nearshore areas. Projected increases in
population and associated growth and development in coastal areas will increase.
More effective management means taking into account nearshore coastal processes and the pathways along which those processes
act in coastal margin and nearshore zones. Restoration or rehabilitation of nearshore physical processes can be accomplished by
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managing the shoreline at a coarser scale, say littoral cell by littoral cell, and by implementing solutions designed to mimic the
functionality of these coastal processes.
Comments from the author: DEFINITIONS
Coastal Margin and Nearshore Areas
• Coastal Margin area - shallow water depths < 3 m
• Nearshore area - water depths > 3 m and < 15 m
Attributes of Landscapes
• Geology - surface and subsurface distribution of geologic materials; soils; hydrophysical characteristics (permeability,
porosity, aquifers, aquatards...).
• Geomorphology - shape, pattern, distribution, and physical features of the land surface; landforms and drainage pattern
(topography, slope, hydrography, channel morphology and bathymetry, connectivity and pattern).
• Land cover - shape, pattern, and distribution ofbiological and anthropogenic features on the land surface; land use.
Acknowledgments
Author: Scudder D. Mackey, Ph.D. Habitat Solutions NA, scudder@sdmackey.com
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