Spatial ecology of the eastern diamond-backed rattlesnake (Crotalus adamanteus)
Type of DegreeThesis
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An animal’s spatial ecology may be governed by variables operating at more than one spatial scale, which underscores the importance of incorporating multiple spatial scales into habitat selection models. This is particularly relevant if robust evaluations of key habitat characteristics are to be made for understudied species in imperiled ecosystems, such as for the eastern diamond-backed rattlesnake (Crotalus adamanteus). We conducted a two-year radio-telemetry study of adult C. adamanteus in southwestern Georgia to determine estimates of home range size, assess multi-scale habitat associations, and investigate the relationship between habitat heterogeneity and home range size. No difference in home range size was detected between male and females and male mean home range size was smaller than that reported from previous studies. We used a multivariate distance-based approach to analyze habitat associations. At the landscape scale, individuals showed a positive association with pine habitat and, within home ranges, there was a negative association with agriculture. Pair-wise comparisons revealed that no one habitat type was selected over another at the landscape scale, but that within home ranges, individuals were located significantly closer to hardwood forests than to agricultural areas. These results are congruent with two previous radio-tracking studies that examined habitat associations of adult C. adamanteus, despite the geographical and ecological disparity of the three study sites (Georgia, Florida, and South Carolina). Furthermore, habitat heterogeneity was inversely related to home range size at multiple spatial scales. Variables representing heterogeneity in landscape configuration, rather than composition, most heavily influenced home range size. This relationship was strongest at the scale representing mean home range size, as well as a scale approximately three times the size of mean home range. From these studies, we recommend that management regimes designed to enhance population size of C. adamanteus emphasize the preservation of pine uplands, limit the conversion of forest to agriculture, and maintain a mosaic of habitat types within a pine matrix. We also stress the need to conduct spatial ecology research at multiple spatial scales and consider the importance of habitat heterogeneity to variations in space use.