Spatial Ecology of the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis) in Indiana

Abstract

Few studies have examined the spatial ecology of the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis). We used radiotelemetry to examine the seasonal home range, movement patterns, and habitat use of 21 individuals within the Blue River drainage of southern Indiana, USA. Individuals were located up to three times weekly from July 2008 through October 2009. Mean 100% minimum convex polygon (MCP) home-range sizes were much larger than previously reported and largest during the summer. Male MCPs were significantly larger than those of females. Mean linear home-range sizes were also significantly longer in the summer, but did not differ between the sexes. Hellbenders moved very little throughout the year (X¯ = 14.1 movements per individual) and over relatively short distances (X¯ = 27.5 m) to nearby shelter rocks. Most Hellbenders were routinely located under large, flat shelter rocks; however, five individuals periodically used bedrock, downed trees, and submerged tree root masses along the riverbank. Habitat use of Hellbenders was similar to that found in other studies, with 79.5% of our locations found on a gravel substrate. Our results provide essential information about a declining, low-density population of Hellbenders in need of management.