Great Lakes Coastal Wetland Monitoring Program (CWMP)
Plants & Animals
As indicators
Plant and animal life reveals the health of coastal wetlands.
Since 2011, UW-Green Bay has been a proud participant in the Great Lakes Coastal Wetland Monitoring Program (CWMP), a binational effort to better understand and protect these vital ecosystems. Wetlands are home to a rich diversity of plants and animals uniquely adapted to the ever-changing coastal environment. CWMP field crews collect data on birds, anurans (frogs and toads), vegetation, fish and invertebrates across Great Lakes wetlands in both the U.S. and Canada. These biotic indicators help monitor and assess wetland health, while also establishing a baseline for tracking future changes in biodiversity and environmental quality—ensuring that the rhythms of nature continue to guide conservation efforts for years to come.
Fast Facts
The Great Lakes Restoration Initiative issued by the U.S. Environmental Protection Agency’s Great Lakes National Program Office helps fund this important project.
Why
Besides providing a home for plants and animals, coastal wetland systems also include important ecosystem services, such as controlling shoreline erosion, improving water quality and drinking water, offering flood protection and supporting recreational activities.
Who
Over 45 UW-Green Bay students, both undergraduate and graduate, have participated in the surveys, including the completion of two master’s theses (Gaul 2017 and Hohman 2019) and undergraduate projects. Investigators at universities and state and federal agencies across the U.S. and Canada collaborate on this project. Dr. Robert Howe, retired Director of the Cofrin Center for Biodiversity (CCB) started this program in 2011. Erin Giese, Associate Director of the CCB, has been coordinating field work for the project since its inception, and now serves as a co-principal investigator.
Where
Student field crews survey for birds and anurans in coastal wetlands as far south as northern Illinois, along the Wisconsin Lake Michigan shoreline, and the southern shoreline of the Upper Peninsula of Michigan along northern Lake Huron. They have visited some of the most pristine wetlands in the entire Great Lakes system including in the far eastern Upper Peninsula in the Munuscong River area.
How We Survey
The CWMP samples over 1,000 coastal wetlands once every five years, though some wetlands are sampled across multiple years. Each year, UW-Green Bay field crews establish sampling locations, or “points,” within the wetlands chosen for sampling and survey them for anurans and birds. Wetlands must be at least 4 ha (9.9 ac) in size, dominated by open herbaceous vegetation (e.g., cattail [Typha spp.]) and connected to and influenced by a Great Lake.
Frog Surveys
Certified anuran field technicians conduct 3-minute unlimited-distance point count surveys three times throughout the spring and summer, in which they record all anurans that they hear no matter how far away they are calling. Each of the three surveys is separated by at least 15 days between early April and mid-July because anurans emerge out of hibernation and become vocal at different times based on overnight temperatures.
Listen to the Frogs
Bird Surveys
Certified bird field technicians conduct two 10-minute unlimited-distance point counts between late May and mid-July. The first count is conducted in the early morning, and the second count is done either in the early morning or late evening. During the first 5 minutes of each survey, a technician records all birds seen or heard. During the second 5-minute period, a broadcast of secretive marsh-nesting bird species is played to elicit feedback from species, such as Least Bittern (Ixobrychus exilis) and Virginia Rail (Rallus limicola).
Hear the Bird Chorus
What We Found
Great Lakes water levels can fluctuate naturally by as little as a few centimeters across days or by over a meter across years. Our field crews have surveyed these plants and animals during significant fluctuations of Great Lakes water levels, including during historic record low water levels in 2013 and then record high or near record high levels in 2017-2021. In those few short years, wetlands that were once shallow with a lot of standing emergent vegetation, like cattail and bulrush, quickly became deeper and wetter when lake levels rose. In some cases, wetlands became completely flooded out without any remaining wetland vegetation.
Different communities of birds and anurans utilize these Great Lakes coastal wetlands during different lake levels. For example, Sandhill Crane (Antigone canadensis), Sedge Wren (Cistothorus platensis) and American toad (Anaxyrus americanus) prefer shallower wetlands during lower lake levels, whereas species like Yellow-headed Blackbird (Xanthocephalus xanthocephalus), Sora (Porzana carolina) and northern leopard frog (Lithobates pipiens) prefer deeper wetlands when lake levels are higher.
2014 - Record Year for Low Water Levels
2017 - High Water Levels
Ask an Expert
Meet Erin Giese, Associate Director of the Cofrin Center for Biodiversity. She champions student experience and truly enjoys training the next generation of scientists. If you have questions about the Coastal Wetland Monitoring, including how to become involved as a student, Erin can help.