Habitat specificity and home‐range size as attributes of species vulnerability to extinction: a case study using sympatric rattlesnakes

Abstract

AbstractLarge home‐range size and habitat specificity are two commonly cited ecological attributes that are believed to contribute to species vulnerability. The eastern diamondback rattlesnake Crotalus adamanteus is a declining species that occurs sympatrically with the more abundant canebrake rattlesnake Crotalus horridus in a portion of the south‐eastern Coastal Plain, USA. In this study, we use the ecological similarities of the two species as experimental controls to test the role of home‐range size and habitat specificity in the imperilment of the eastern diamondback rattlesnake. We used analysis of variance to investigate differences in home‐range size between the two species, and home‐range selection was modeled as habitat use versus availability with a case control sampling design using logistic regression. We failed to detect differences in home‐range size between the two species; therefore, we could not identify home‐range size as an attribute contributing to the imperilment of eastern diamondback rattlesnakes. Eastern diamondback rattlesnakes selected pine savannas to a degree that suggests that the species is a habitat specialist. Of the two factors examined, habitat specificity to the imperiled longleaf pine ecosystem may be a significant contributor to the decline of the eastern diamondback rattlesnake.