Snake co-occurrence patterns are best explained by habitat and hypothesized effects of interspecific interactions
Article first published online: 2 SEP 2013
© 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society
Journal of Animal Ecology
Volume 83, Issue 1, pages 286–295, January 2014
How to Cite
Steen, D. A., McClure, C. J. W., Brock, J. C., Craig Rudolph, D., Pierce, J. B., Lee, J. R., Jeffrey Humphries, W., Gregory, B. B., Sutton, W. B., Smith, L. L., Baxley, D. L., Stevenson, D. J., Guyer, C. (2014), Snake co-occurrence patterns are best explained by habitat and hypothesized effects of interspecific interactions. Journal of Animal Ecology, 83: 286–295. doi: 10.1111/1365-2656.12121
- Issue published online: 18 DEC 2013
- Article first published online: 2 SEP 2013
- Accepted manuscript online: 29 JUL 2013 12:05AM EST
- Manuscript Accepted: 16 JUL 2013
- Manuscript Received: 14 MAY 2013
- Department of Defense's Strategic Environmental Research and Development Program (SERDP). Grant Number: SI-1696
- Florida Fish and Wildlife Conservation Commission's Wildlife Legacy Initiative program and the U.S. Fish and Wildlife Service's State Wildlife Grants program. Grant Number: SWG 05-020
- University of Florida and Joseph W. Jones Ecological Research Center
- Coluber ;
- Crotalus ;
- detection probability;
- Elaphe ;
- occupancy modelling;
- Pantherophis ;
- Snakes often occur in species-rich assemblages, and sympatry is thought to be facilitated primarily by low diet overlap, not interspecific interactions.
- We selected, a priori, three species pairs consisting of species that are morphologically and taxonomically similar and may therefore be likely to engage in interspecific, consumptive competition. We then examined a large-scale database of snake detection/nondetection data and used occupancy modelling to determine whether these species occur together more or less frequently than expected by chance while accounting for variation in detection probability among species and incorporating important habitat categories in the models.
- For some snakes, we obtained evidence that the probabilities that habitat patches are used are influenced by the presence of potentially competing congeneric species. Specifically, timber rattlesnakes (Crotalus horridus) were less likely than expected by chance to use areas that also contained eastern diamond-backed rattlesnakes (Crotalus adamanteus) when the proportion of evergreen forest was relatively high. Otherwise, they occurred together more often than expected by chance. Complex relationships were revealed between habitat use, detection probabilities and occupancy probabilities of North American racers (Coluber constrictor) and coachwhips (Coluber flagellum) that indicated the probability of competitive exclusion increased with increasing area of grassland habitat, although there was some model uncertainty. Cornsnakes (Pantherophis guttatus or Pantherophis slowinskii) and ratsnakes (Pantherophis alleghaniensis, Pantherophis spiloides, or Pantherophis obsoletus) exhibited differences in habitat selection, but we obtained no evidence that patterns of use for this species pair were influenced by current interspecific interactions.
- Overall, our results are consistent with the hypothesis that competitive interactions influence snake assemblage composition; the strength of these effects was affected by landscape-scale habitat features. Furthermore, we suggest that current interspecific interactions may influence snake occupancy, challenging the paradigm that contemporary patterns of snake co-occurrence are largely a function of diet partitioning that arose over evolutionary time.