Schantz, Kris Alane. Characterization of landscape-scale habitat use by timber rattlesnakes (Crotalus horridus) within the Ridge and Valley and Highlands regions of New Jersey. Retrieved from http://dx.doi.org/doi:10.7282/T3JS9QNM
DescriptionRegulations and a lack of understanding the habitat needs of timber rattlesnakes (Crotalus horridus) on a landscape-scale have limited conservation efforts. With better information land managers and planners could implement strategies that protect suitable habitats from development and other human activities. While studies have shown microhabitat characteristics play a role in habitat selection by timber rattlesnakes, it remains unclear if large-scale features, other than rock outcrops, talus slopes and canopy, also impact site selection. I compared the habitat use by two metapopulations of timber rattlesnakes in northern New Jersey with available habitats using GIS data layers to identify the snakes' macrohabitat preferences. The results showed snakes used habitats with slightly more open canopy, closer to rock outcrops, and farther from roads, human development, forest edge (an interface between any habitat and forests with >50% canopy closure) and streams and rivers (>10m wide) than randomly sampled locations. Additionally, I developed a model and distribution map of potential areas where hibernacula may exist in northern New Jersey by first testing habitat and topographic variables to determine the predictors of suitable habitat for hibernacula. In 2004, elevation, sun index, deciduous wetlands and slopes (0-20%) were the most influential features in predicting suitable habitat for hibernacula. Slopes (0-20%) and deciduous wetlands were negatively associated with hibernacula indicating that areas containing shallow slopes and/or deciduous wetlands were less likely to support hibernacula. Sun index indicated that hibernacula are most likely to be found in areas with steep slopes and southerly aspects, and elevation, having the least influence in predicting suitable habitat for hibernacula, showed the likelihood of hibernacula presence increased with increasing elevation. In 2009, with the addition of interior forest hibernacula in the dataset, only slope (0-20%) and sun index were influential features in predicting suitable habitat for hibernacula indicating that the potential for hibernacula presence increased in areas with steep slopes and southerly aspects. Landscape modeling using GIS-ready habitat features can help biologists identify habitats essential for populations and metapopulations, and target conservation of those habitats and connecting corridors for long-term timber rattlesnake viability.