Temporal variability of overwintering conditions for a species-at-risk snake: Implications for climate change and habitat management

The suitability of overwintering habitat in response to temporal fluctuations in winter temperatures and water table position, and variability in timing and intensity of snowfall and rainfall is critical to informing management strategies for climate-sensitive species such as the Eastern Massasauga rattlesnake (Sistrurus catenatus). Important subterranean conditions contributing to the suitability of overwintering habitat for S. catenatus includes the availability of an unflooded space and temperatures above 0 °C which is conceptualized as the resilience zone. Here, we show that the timing and duration of resilience zone loss varies between years and among sites in response to variable weather conditions. Peatland habitat occupied by snakes lost the resilience zone fewer times and for shorter durations than unconfirmed habitat. In some cases occupied habitat continuously provided a resilience zone, suggesting that snakes may only be able to tolerate short periods of unsuitable conditions. As expected, larger precipitation events resulted in greater reduction of the resilience zone size. In particular, rain on snow events resulted in the greatest change in resilience zone size and could increase the risk of mortality events. With extreme weather-related events predicted to increase with climate change, long-term conservation of climate-sensitive species should focus on protecting habitats that are naturally resilient to changing and variable weather conditions and identifying vulnerable habitats that would benefit from additional research on adaptive management strategies.