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

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

J. L. Waldron¹, S. H. Bennett², S. M. Welch1, M. E. Dorcas³, J. D. Lanham¹ & W. Kalinowsky⁴

¹ Department of Forestry and Natural Resources, Clemson University, Clemson, SC, USA
² South Carolina Department of Natural Resources, Columbia, SC, USA
³ Department of Biology, Davidson College, Charlotte, NC, USA
⁴ South Carolina Department of Natural Resources, Webb Wildlife Center, Garnett, SC, USA

Abstract
Large 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.

Keywords: eastern diamondback rattlesnake; canebrake rattlesnake; Crotalus adamanteus; Crotalus horridus; home range; habitat specificity; habitat selection; pine savanna.

Correspondence
Jayme L. Waldron
Current address: Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA.
Tel: 1 843 782 3206
Email: waldron@srel.edu

Waldron, J. L., S. H. Bennett, S. M. Welch, M. E., Dorcas, J. D. Lanham, & W. Kalinowsky. 2006. Habitat specificity and home-range size as attributes of species vulnerability to extinction: a case study using sympatric rattlesnakes. Animal Conservation 9(4): 414-420.