Rediscovery of Cambarus diogenes (Devil Crayfish) in Pennsylvania

North American crayfish biodiversity is in need of conservation attention, which requires monitoring to assess the status of potentially imperiled species. Pennsylvania has a long history of crayfish studies, dating back to the early 1900s and continuing today. We sampled 37 new and historical sites in southeastern Pennsylvania in an effort to locate remnant populations of Cambarus diogenes (Devil Crayfish), an ecologically important burrowing crayfish. While we did not find Devil Crayfish at any historical sites, we discovered a single population in Neshaminy State Park, indicating a decline in this species' range in Pennsylvania since the last survey, circa 1905. We attribute the statewide decline of Devil Crayfish to an inherently limited amount of suitable habitat, urbanization, and biological invasions, and recommend that steps be taken to protect this species.