An Amphibian and Reptile Inventory of Isle Royale National Park

Casper, Gary

The National Park Service, Great Lakes Network Office, commissioned a herpetological inventory of Isle Royale National Park, Michigan, in 2004. Isle Royale National Park is actually a collection of over 400 islands (one large island surrounded by many smaller islands), covering approximately 54,228 ha (134,000 acres) in western Lake Superior. The park was federally designated a wilderness area on October 20, 1976, and an International Biosphere Reserve in 1980. The protected area includes submerged land extending 7.2 km (4.5 miles) into Lake Superior, the largest freshwater lake in the world. Objectives of this study were to: 1) supplement existing inventory data for amphibians and reptiles in the park, and 2) better assess the status of species listed as “Unconfirmed” or “Probably Present” in the park’s species list, which was produced in 2003. Based on the 2003 list status and additional review of regional status, we targeted six species for surveys. We reviewed records for 232 museum specimens from the park, frog and toad survey data provided by the park, and all available literature and observations, both published and unpublished. Sampling was performed over three periods in 2004 and 2005, utilizing visual searches, calling frog surveys, aquatic funnel traps, and artificial cover objects. Thirty-five new voucher specimens were collected from the park. No new species were documented, but nine amphibian and three reptile species were confirmed in the park, with one more remaining unconfirmed. Recommendations are made regarding inventory, monitoring, and management of amphibians and reptiles in the park.

An Amphibian and Reptile Inventory of Isle Royale National Park

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