How habitat edges affect the spatial dynamics of snakes has become an increasingly popular subject because of a massive increase in anthropogenic edges in many landscapes. Here, we used a novel randomization-based procedure to examine patterns of edge association for the Timber Rattlesnake (Crotalus horridus) within upland forest in St. Louis County, Missouri. For each set of locations, the minimal distance from each location to the nearest edge feature was measured, averaged, and compared to an expected null distribution of average minimal distances (AMDs) under the assumption that points are randomly located with respect to edges. The significance of the observed value was estimated by determining the proportion of AMDs from the randomized set that were equal to or less than the observed average distance. Results indicated considerable variation from year to year in test results for individuals, resulting in variation in the results of combined significance tests for subgroups (i.e., males, females, and gravid females). Although results for different edge types were not compared statistically, our results indicated that individuals were found most frequently in nonrandom proximity to fence edges. In general, results were consistent with previous studies of habitat selection in midwestern snakes, which failed to find a consistent association between snakes and edges.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology