Conservation and Distribution of Creaserinus fodiens (Digger Crayfish) in Pennsylvania.

Abstract

Because crayfishes are the 4^th most imperiled group of aquatic or terrestrial organisms in North America, agency efforts to assess the status of the fauna have increased in recent decades. Historically these assessments have focused on stream-dwelling species while primary burrowing crayfishes have been overlooked. Pennsylvania has initiated numerous surveys to determine modern distributions and conservation status of its crayfish fauna and in 2014 began a primary burrowing crayfish survey. These efforts led to the first documented record of Creaserinus fodiens (the Digger Crayfish) in the state. In 2017 a dedicated effort to determine the distribution and conservation status of C. fodiens commenced in Erie and Crawford counties. Initially, visual surveys were conducted for suitable habitat (roadside ditch, ephemeral pool, wetland, etc.) and/or burrows with chimneys, with the goal of collecting presence/absence data. Sites with suitable habitat, burrows, or chimneys were subsequently sampled for crayfishes. If water depth was <0.25 m collections were made via dipnet and if water depth was ≥0.25 m the site was trapped for 3 months. Each site was analyzed for percentage of land use type using the National Land Cover Database with a 200 m diameter buffer. These data were modeled using logistic regression to elucidate habitat preferences of C. fodiens. NatureServe’s ranking system was used to designate conservation status in the state of Pennsylvania. Two populations of C. fodiens have been discovered to date with additional sampling to take place in 2019.