Patuxent Wildlife Research Center

NAAMP III Archive - accepted papers
Home | Archive by Alphabetical Order | Archive by Category

Overview of the Great Lakes Declining Amphibians Working Group

Abstract of presentation at Deformed Frog Workshop, US EPA, September 24, 1996, Duluth, MN

G.S. Casper

The Great Lakes Declining Amphibians Working Group (GLWG) is a division of the IUCN/Species Survival Commission Declining Amphibian Populations Task Force. This Task Force was formed to address a worldwide decline in amphibian populations. Various regional working groups have been set up to develop regional research and conservation initiatives. The GLWG:

Occasional conferences are held. Abstracts from the first conference, in March of 1996, are available on the GLWG World Wide WEB. To participate in the GLWG, or to inquire about amphibians in the region, contact the chairperson, Gary S. Casper.

The Great Lakes region is home to 10 species of salamanders and 15 species of anurans. The most serious decline in the region has been in the Blanchard's Cricket Frog, Acris crepitans. This species is now apparently extirpated from Minnesota, and populations are drastically reduced in Wisconsin and Michigan. The reasons for this decline, which began in the 1960s, are unknown. Smaller but significant declines in most species in the region are apparent, mainly due to habitat loss. Leopard Frog, Rana pipiens, populations crashed in the 1970s, and have partially recovered. Concern has also been raised over possible declines in the Cope's Gray Treefrog, Hyla chrysoscelis, the Spring Peeper, Pseudacris crucifer, and the Bullfrog, Rana catesbeiana.

Several research and monitoring programs are underway in the region. The Wisconsin Frog & Toad Survey is the longest running amphibian monitoring program in the nation, with about 14 years of data now recorded. The Wisconsin Herpetological Atlas Project is 10 years running. Minnesota began anuran calling surveys in 1995, with Michigan following suit in 1996. The Minnesota Pollution Control agency began investigating the unsettling frequency of deformed frogs in that state in 1995, and the Wisconsin Department of Natural Resources started tracking deformed frog reports in 1996. Various smaller research projects are being conducted throughout the region, targeting specific species or localities, on a variety of problems, from the effects of PCB contaminants on amphibian reproduction, and validation studies of survey techniques, to implementing salamander surveys into high school curricula. New books on Minnesota and Wisconsin amphibians and reptiles were published in 1996. A book on Michigan amphibians was published in 1992, and a new book on the amphibians and reptiles of the Great Lakes is due in 1997. The GLWG makes an effort to track all amphibian-related projects in the region, and act as a central clearing house and peer network. Gary S. Casper
Coordinator, Wisconsin Herpetological Atlas Project
Chair, Great Lakes Declining Amphibians Working Group

Please direct correspondence for Gary S. Casper to:
          Vertebrate Zoology Section
          Milwaukee Public Museum
          800 W. Wells St.
          Milwaukee, WI 53233
          Voice: (414)278-2766
           Fax:    (414)278-6100
          Back to text reference.


U.S. Department of the Interior
U.S. Geological Survey
Patuxent Wildlife Research Center
Laurel, MD, USA 20708-4038
Contact: Sam Droege, email:
Last Modified: June 2002