Mortality Risk Associated With Urban Land Use for Adult Eastern Diamondback Rattlesnakes (Crotalus adamanteus)

Snakes have been a traditionally under-represented organism in urban ecology, but they face similar, if not greater challenges in the face of growing urban sprawl. Eastern diamondback rattlesnakes (Crotalus adamanteus, EDBs) are under consideration for listing under the Endangered Species Act due to population declines resulting from historical human persecution and habitat loss. This study used radio-telemetry data from a long-term monitoring project of adult EDBs on a developed sea island in South Carolina, USA. I reclassified a National Land Cover Dataset to reflect relative mortality risk for snakes attempting to move through the landscape. High-risk cover types included all developed areas such as roads, parking lots, buildings, and golf courses. Low-risk cover types included forested/naturally vegetated areas where human activity was typically low. To assess when and why snakes may choose to cross high-risk areas, I examined the frequency and probability of high-risk crossings as a function of demographic, spatial, and temporal predictors in mixed effect models that included individuals as a random effect. Reduced activity and movement associated with cool winter temperatures reduced the number of overall crossings, but there was no detectable difference between sexes, even within seasons. Larger home ranges and those with a proportionately greater amount of high-risk cover within the home range were positively correlated with number of high-risk crossings. Considerations for conservation in urban landscapes include assessing the potential impact of urban development on neighboring EDB populations, as well as for managing wildlife-human conflicts