STATE OF THE GREAT LAKES 2005
WHAT ARE THE CURRENT PRESSURES IMPACTING LAKE ERIE?
..and use practices, nutrient inputs, and the introduction of non-native invasive species are the greatest threat;
to the Lake Erie ecosystem. Natural resource use and chemical and biological contaminants also continue to
impact the Lake Erie basin.
Pressures and Actions Needed
Land use
Land use changes, including urban development and
sprawl, intensification of agriculture, and
construction of shore structures continue to
negatively impact water quality and quantity, and
fish and wildlife habitats in Lake Erie and its
tributaries. Unless significant changes are made, this
trend is expected to continue as demand for land
conversion and use in the Lake Erie basin intensifies.
In some areas of the Lake Erie watershed, over 90
percent of the land has been converted to
agriculture, urban and industrial use. A major focus
on the rehabilitation of remaining natural habitats
and the physical processes that support them is
required in order to restore Lake Erie's aquatic
ecosystems. Through best management practices, we
must undertake rural, urban and industrial land use
activities that result in either gains or no net loss in
the amount and quality of natural habitats and/or
water quality improvements. Development of
protected areas networks and other planning tools,
will protect existing habitats and the processes that
maintain them, including habitat corridors that
connect lake, wetlands and upland habitats.
Non-native invasive species
Established non-native aquatic and terrestrial
invasive species have irreversibly altered the Lake
Erie ecosystem. The invasion of zebra mussels in the
late 1980s triggered a tremendous ecological change
in Lake Erie, as the mussels altered food web
dynamics, habitats, and the cycles of nutrients and
contaminants in the ecosystem. Additional invasive
species such as the quagga mussel, round goby, and
several large zooplankton species have further
altered the Lake Erie ecosystem and may
Lake Superior
Lake Michigan
Lake Huron
Lake Ontario
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Lake Erie
actually render the ecosystem more susceptible to
future invasions. Increased water transparency due to
the combined effects of nutrient control and zebra
mussel filtering has reduced habitat for walleye,
which avoid high light conditions. Increased water
transparency combined with lower Lake Erie water
levels has resulted in an increase of submerged
aquatic plants.
New non-native invasive species must be prevented
from colonizing the Lake Erie ecosystem. The spread
of already established non-native invasive species
must be controlled and reduced where feasible.
Lake Erie beach covered by zebra mussel shells. Photo:
U.S. EPA Great Lakes National Program Office.
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LAKE ERIE PRESSURES
Nutrient inputs
Although phosphorus controls have resulted in
tremendous improvements in Lake Erie water quality
over the past two decades, continued nutrient inputs
from both point and non-point sources still reduce
the use of beaches, cause changes in aquatic
community structure, and increase algal blooms in
Lake Erie, especially in nearshore areas and
tributaries.
Nutrient inputs from both point and non-point
sources must be managed to ensure that ambient-
nutrient concentrations are within bounds of
sustainable watershed management. Best
management practices and point-source controls
need to be implemented with consideration of the
ecological requirements for the maintenance or
recovery of healthy aquatic communities in the
watershed, the hydrologic cycle, and water usage. In
addition to phosphorus, nitrate inputs must be
included in assessments of watershed and basin
nutrient impacts.
Natural resource use
Natural resource use, including commercial and
sport fishing, hunting, trapping, logging, and water
withdrawal, has negative impacts on target species
and habitats of the Lake Erie ecosystem.
Natural resource use must be sustainable, managed
to ensure that the integrity of existing healthy
ecological communities are maintained and/or
improved, while also providing benefits to
consumers.
Chemical and biological contaminants
Toxic contaminants are introduced into the Lake Erie
ecosystem via combined inputs from point and non-
point sources within the basin, loadings from the
Detroit River, and upstream and long-range
atnospheric transport from regional and global
sources. Toxic chemicals degrade watersheds by
impacting water quality, potentially affecting
drinking water, fish and wildlife consumption by
humans, and fish and wildlife populations. In
addition, biological contaminants such as Type E
botulism bacterium may have caused a number of
fish, fish-eating bird, and mudpuppy (an aquatic
salamander) die-off events in the eastern basin of
Lake Erie.
The concentrations of chemical contaminants within
the basin are managed according to the principle of
virtual elimination. Effective management of local
point and nonpoint sources and adoption of
pollution-prevention practices have improved
watershed and basin ecosystem quality. However,
managing legacy contaminants in sediments and
landfills and broad-based actions such as those
promoted in the Great Lakes Binational Toxics
Strategy and the United Nations Agenda 21, which
address global atmospheric pollutant transport, are
also required to fully reach the objective of virtual
elimination of contaminants.
To Learn More
For further information related to the state of Lake
Erie, refer to the State of the Great Lakes 2005 report,
which, along with other Great Lakes references, can
be accessed at www.epa.gov/glnpo/solec. The Lake
Erie Lakewide Management Plan 2004 can be found
atwww.epa.gov/greatlakes/erie.html.
Layers of Cladophora algae
along a Lake Erie rocky
shoreline. Photo: Upper
Thames River Conservation
Authority.
02/06
EPA 905-F-06-910
IISG-06-03
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