Current distribution and status of amphibians and reptiles in Will County, Illinois

The distribution of amphibians and reptiles in Will County, Illinois, was assessed using museum records and results from 58 surveys conducted between 1986 and 2009 on lands owned and managed by the Forest Preserve District of Will County (FPDWC) and Illinois Department of Natural Resources (IDNR). One hundred and twenty sources of information were examined including technical reports, theses, dissertations, and personal data belonging to the authors. Forty-eight species (19 amphibians, 29 reptiles) were documented by photos or specimens from Will County. Eleven species were determined widespread and common, 6 were categorized as patchy distributions and are uncommon or locally common, and 23 were found to have restricted distributions and are considered rare, including seven state-listed species. One of those state-listed species (Sistrurus catenatus) is likely extirpated. Eight species had undetermined distributions, four of them of questionable occurrence. One of the questionable species (Anaxyrus fowleri) is no longer included in the current list of Will County herpetofauna because it has been determined to have been an introduction and no known population exists. For three others Terrapene carolina, Pantherophis spiloides, Nerodia rhombifer) we were unable to conclusively interpret their records and they are assigned questionable status until further records confirm existence of viable, self sustaining populations. Of seven state-listed species (four threatened, three endangered), one may be extirpated (Sistrurus catenatus). Lithobates sylvaticus, Hemidactylium scutatum, Ambystoma texanum, and Eurycea cirrigera are glacial relicts that are highly vulnerable to extirpation due to pollution, isolation, and a warming climate. Presently, 43 species (18 amphibians, 25 reptiles) are known to occur in Will County, making it the most species-rich county in the Chicago region.