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| Western Ratsnakes (Pantherophis obsoletus) |
Predicting the effects of global climate change on species interactions has remained difficult because regional climate models and the microclimates experienced by organisms are not always in sync. In a new paper George et al. (2017) evaluated resource selection in a predominant ectothermic predator using a modeling approach that permitted them to assess the importance of habitat structure and local real-time air temperatures within the same modeling framework. The authors radio-tracked 53 western ratsnakes (
Pantherophis obsoletus) from 2010 to 2013 in central Missouri, USA. The researchers used study sites where this species was previously linked to prey population demographics. Bayesian discrete choice models within an information theoretic framework were used to evaluate the seasonal effects of fine-scale vegetation structure and thermal conditions on ratsnake resource selection. Ratsnake resource selection was influenced most by canopy cover, canopy cover heterogeneity, understory cover, and air temperature heterogeneity. Ratsnakes preferred habitats with greater canopy heterogeneity early in the active season, and greater temperature heterogeneity later in the season. This seasonal shift potentially reflects differences in resource requirements and thermoregulation behavior. Predicted patterns of space use indicate that ratsnakes preferentially selected open habitats in spring and early summer and forest–field edges throughout the active season. The results show that downscaled temperature models can be used to enhance our understanding of animal resource selection at scales that can be addressed by managers. The authors suggest that conservation of snakes or their prey in a changing climate will require consideration of fine-scale interactions between local air temperatures and habitat structure.
Citation
George AD, Connette GM, Thompson FR, Faaborg J. 2017. Resource selection by an ectothermic predator in a dynamic thermal landscape.
Ecology and Evolution. 2017.
