STATE  OF  THE GREAT LAKES 2005
               WHAT IS THE STATE OF GREAT LAKES AMPHIBIANS?
    Currently, the loss and degradation of wetland habitats poses a major threat to Great Lakes amphibian
                                           populations.
The Issue
Amphibians living in Great Lakes wetlands
generally remain in one area throughout their
lifetime. They also have semi-permeable skin,
meaning that substances are able to pass through
their skin and into their bodies. Because of these
features, amphibians are likely to be more sensitive
to, and indicative of, local sources of wetland
contamination and degradation than are most other
animals.

The Indicator
There are numerous amphibian species in the Great
Lakes region, and most of these species are
associated with wetlands during part or all of their
life cycle. Measures of abundance, distribution, and
diversity of amphibians provide needed information
about their population trends and can contribute to
more effective, long-term conservation strategies. In
addition to providing valuable assessments of the
health of amphibian populations, this information
also indirectly evaluates the condition of coastal
wetland habitat.

The Assessment
Currently, the assessment for the state of amphibians
in the Great Lakes basin is based on frogs and toads
only. Since 1995, the Great Lakes Marsh Monitoring
Program (MMP) volunteers have collected frog and
toad data throughout the Great Lakes region. Frogs
and toads surveyed by this program are typically
dependent on marsh habitat for their spring and
early summer mating rituals.

Thirteen frog and toad species were recorded
between 1995 and 2002. Spring peeper was the most
frequently detected species, and was commonly
detected in full chorus when it was encountered.
Green frog, grey treefrog, American toad, and
northern leopard frog were also commonly detected
species. Bullfrog, chorus frog, and wood frog were
detected less frequently and pickerel frog,
Blanchard's cricket frog, Cope's grey treefrog, mink
frog, and Fowler's toad were detected infrequently.

Trends in frog and toad occurrence were assessed for
eight species that are commonly detected on MMP
routes. Statistically significant declines in occurrence
trends were detected for American toad, chorus frog,
green frog, and northern leopard frog.
Northern leopard frog. Photo: Allen Chartier.


Current Actions
Data collected by the Marsh Monitoring Program will
serve as baseline data with which to compare future
survey results. Additional years of data will help to
distinguish whether the patterns observed indicate
long-term trends or simply natural variation in
population size. Marsh Monitoring Program data are
being evaluated to gain a better understanding of
Great Lakes coastal wetlands conditions.

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WHAT IS THE STATE OF GREAT LAKES AMPHIBIANS?
Reporting will also be improved by the establishment
of a network of survey routes that accurately
represent the full spectrum of marsh habitat quality
in the Great Lakes basin. Development of such a
network is underway, along with the following
actions: the development of an amphibian indicator
as an index for evaluating coastal wetland condition;
the establishment of precise geo-referenced locations
for all MMP routes to enable future spatial analyses;
and continued recruitment efforts and training for
volunteer participants.

Actions Needed
Effective monitoring of Great Lakes amphibians will
require the collection of many years of data, using a
standardized protocol, over a large geographic
expanse. Since amphibian populations naturally
fluctuate over time, a five-year timeframe would
likely allow for noteworthy changes in populations
to be detected. Further work is also required to
determine the relationship between calling codes
used to record amphibian occurrence and count
estimates.
To Learn More
For further information about amphibians in the
Great Lakes, refer to the State of the Great Lakes 2005
report which, along with other Great Lakes
references, can be found at
www.epa.gov/glnpo/solec. For more information on
the Great Lakes Marsh Monitoring Program, visit
www.bsc-eoc.org/mmpmain.html.
Other impacts that are detrimental to amphibian and
wetland health also need to be addressed, such as
inputs of toxic chemicals, nutrients and sediments.
More rigorous studies will relate trends in species
occurrence or relative abundance to environmental
factors.
 American toad. Photo:
 www.glfc.cf s.nrcan.gc.ca/landscape/herp_e.html
                                                                                                    02/06
                                                                                          EPA 905-F-06-904
                                                                                          IISG-05-30

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