Habitat selection by grassland snakes at northern range limits: Implications for conservation |
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Authors: | Jessica A Martino Ray G Poulin Dennilyn L Parker Christopher M Somers |
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Institution: | 1. Biology Department, University of Regina, 3737 Wascana Parkway, Regina, SK, Canada S4S 0A2;2. Biology and Environmental Studies, Royal Saskatchewan Museum, Regina, SK, Canada S4P 2V7;3. Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4 |
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Abstract: | Animal populations at northern range limits may use habitat differently from those at range cores, requiring distinct conservation plans. Snakes are ectotherms that often have very specific requirements, but few studies have focused on the effect of northern latitudes on habitat selection by grassland snakes. We studied movement and habitat selection of 2 sympatric snake species at their northern range limits on the North American Great Plains: the eastern yellow-bellied racer (Coluber constrictor flaviventris, hereafter racer), a Threatened species in Canada, and the bullsnake (Pituophis catenifer sayi), which is listed as Data Deficient. Both of these species are potentially vulnerable to extinction in Canada because of habitat loss. Snakes from our study populations traveled up to 10-times farther from winter dens and occupied home ranges 3–104 times larger than populations further south. Both snake species moved from winter dens in the slopes of a major river valley to habitat in adjacent lowlands, including riparian zones (racers) and hilly areas with native grass species (bullsnakes). Multivariate modeling revealed that proximity to retreat sites was a significant predictor of snake site use for both species. Considering the need for winter dens and summering areas, our data suggest that snakes in northern latitudes should ideally have much larger protected areas compared to snakes near the core of their range. An alternative strategy is to conserve corridors linking wintering dens and summer habitats. Retreat sites such as burrows and shrubs are critical components of local habitat and should be included in conservation plans. © 2011 The Wildlife Society. |
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Keywords: | bullsnake Coluber constrictor flaviventris eastern yellow-bellied racer habitat use northern populations Pituophis catenifer sayi |
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