The Rocky Road to Eastern Hellbender (Cryptobranchus a. alleganiensis) Recovery in Ohio: An Evaluation of Habitat in Ohio's Streams

Abstract

Determining habitat characteristics that influence the contemporary distribution of species is imperative for effective conservation planning. The Eastern Hellbender (Cryptobranchus a. alleganiensis) reaches its Midwestern northern range limit in Ohio, U.S.A.Most previous studies have focused on habitat within the mountainous core of the species' range. We assessed physical and chemical habitat characteristics across the extant range of the Hellbender in Ohio. Physical habitat characteristics were similar to habitat across the range. Hellbenders occupied stream segments typically in contact with steep hillsides that are the source of large shelter rocks. Stream substrate consisted of large boulders and cobble and contained moderate proportions of gravel and sand. Both water temperature (max = 29.4–33.0 C) and conductivity (range = 284–1323 µS/cm) were elevated in Ohio streams. Historic alterations to streams in combination with distinct hydrologic regimes and geology have resulted in habitat characteristics not commonly reported elsewhere. This may have contributed to Hellbender populations being dominated by large adults. Developing an understanding of the role habitat structure and perturbations play in egg and larval survival is critical for the implementation of effective conservation strategies.