Valuable Research on Protected Frog Populations Found in Illinois

Article by: Jen Young, NGRREC/L&C Marketing and PR,

EAST ALTON – The National Great Rivers Research and Education Center (NGRREC) is currently in its second year of a treefrog research project taking place in southern Illinois’ bald cypress swamps.

Currently, bird-voiced treefrogs are listed as threatened in Illinois and the habitat they rely on, bottomland forest swamps, are rapidly declining and listed as wetlands of international importance. The goal of this project is to provide a more accurate assessment of population, abundance, growth and survival of bird-voiced treefrogs in southern Illinois.

“Overall, this species is very understudied, with a majority of the research taking place in the 1990s,” said Jessica Mohlman, assistant scientist and research coordinator. “The previous studies also focused on only observational findings including diet and mating. We are now tracking individuals and gathering additional information including weight and length to better understand the species and its status in the state.”

This study takes place across ten sites located in Eastern Shawnee National Forest and Cache River-Cypress Creek. Each of the sites includes 50 traps, for a total of 500 traps included in this study. Each frog captured is scanned for a Passive Integrated Transponder (PIT) tag that has a unique identification number, similar to a microchip utilized in dogs and cats. If it has previously been caught, researchers determine the frog’s sex, age, weight and length. If it is a new capture, a PIT tag is added to a frog. All frogs are released back into the swamp.

“The Illinois Department of Natural Resources and the Illinois Natural History Survey both have been crucial partners allowing access to wetlands and making sure all staff are properly trained to handle treefrogs safely.” Environmental Technician Jen Hemphill said.

The main focus of this research study is bird-voiced treefrogs, however, green and gray treefrogs are also being caught and tagged to understand their population levels as well.

One of the major threats to biodiversity loss is the alteration and degradation of habitats. In Illinois, over 90% of its original wetland area have already been lost. Naturally occurring wetlands also help our communities by reducing flooding and they function as a filter, working to remove pollution from water runoff before it reaches a creek or river.

“Wetlands are rich in biodiversity and beauty and are one of the most important habitat types in the world,” said Mohlman. “Go out to a local wetland and explore their beauty. Listen to the calls of the frogs and the birds.”

For more information contact Jessica Mohlman at or (618) 468-2833.

National Great Rivers Research and Education Center (NGRREC ℠ )

Founded in 2002 as a collaborative partnership between the University of Illinois at Urbana-Champaign and Lewis and Clark Community College, NGRREC is dedicated to the study of great river systems and the communities that use them. The center aspires to be a leader in scholarly research, education, and outreach related to the interconnectedness of large rivers, their floodplains, watersheds, and their associated communities.

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