Amphibian declines during a 50-year period in south central Pennsylvania

During 1967–2017, I surveyed Eastern hellbenders (Cryptobranchus alleganiensis alleganiensis) at Sherman’s Creek, Perry County, Pennsylvania, and four hylid frog species along five sections of roads in Adams, Cumberland, Franklin, Perry, and York counties, for a total of 33.55 km. An abrupt extirpation was detected in Eastern hellbenders. Eastern gray treefrog (Hyla versicolor) distribution varied among sites over time. By the early 2000s, Northern cricket frogs (Acris crepitans) were no longer heard. Upland chorus frogs (Pseudacris feriarum) were no longer heard from Cumberland Valley sites since the mid-1970s and York County sites since 1994. In most sites, disappearance of upland chorus frogs was preceded by colonization of spring peepers (Pseudacris crucifer), which continued to be heard through the rest of the study. Although the Sherman’s Creek site changed in several notable habitat features, other sites of this study superficially remained structurally stable over the course of the study. Factors including climate change, Batrachychytrium dendrobatidis fungus, and endocrine disruptors are discussed as possible causes of the observed changes among species.