Endangered Frog Emerges

 
A researcher searches for Blanchard’s cricket frogs in a back channel near the Mississippi River. Photo courtesy of Gary Casper.

A researcher searches for Blanchard’s cricket frogs in a back channel near the Mississippi River. Photo courtesy of Gary Casper.

In 2014 we began annually monitoring frogs utilizing bioacoustic methods with the Mississippi National River and Recreation Area. Upon analyzing the sounds recorded near Pigs Eye Lake, we were surprised to discover a Minnesota Endangered Species, the Blanchard’s cricket frog (Acris blanchardi) calling from an industrial backwater. Subsequent annual surveys in cooperation with the Minnesota DNR and Macalester College, and funded by the National Park Service, targeted similar habitats of floodplain backwaters downstream from the confluence with the Minnesota River. The species was absent from many sites sampled but we have now found it at 12 sites. Most sites have only a few calling males, sometimes not persisting over multiple years. At least one more robust population, however, persists in Inver Grove Heights.

Blanchard’s cricket frog. It's covered in green algae and is a mellow green with black spots along it's back and legs. Photo courtesy of Gary Casper.

Blanchard’s cricket frog. Photo courtesy of Gary Casper.

It was surprising to find an endangered frog in urban backwaters. Blanchard’s cricket frog began declining decades ago and was not being reported from the annual statewide frog and toad survey in this region. The fact that it has persisted under the radar in the Twin Cities metro area is encouraging. These frogs need winter hibernating sites that are frost free. They occupy floodplain habitats that provide slow backwaters or isolated pools only occasionally flooded, with native vegetation. Expanding protected riparian green space, controlling introduced species, maintaining and enhancing native shoreline and floodplain vegetation, improving water quality, and testing populations for disease would all improve habitat for this species. It is also important that we continue monitoring to better understand where to prioritize habitat preservation, and to track how these frogs are doing. Volunteers can assist this effort by submitting any observations to HerpMapper.org.

The National Park Service Western Great Lakes Network field guide is available for purchase. This book is designed for the field. It is fully waterproof and ready to go mucking with you this season! ALL proceeds go to wetland and amphibian conservation.

Purchase here: Field Guide to Amphibian Eggs and Larvae of the Western Great Lakes

 
parkconnection