Eastern Massasauga rattlesnake : evaluating the effectiveness of mitigation structures at the population level

Abstract

As reptile populations worldwide decline, construction and monitoring of road mortality mitigation measures is becoming common. I studied the effectiveness of barrier fencing at preventing Eastern Massasauga rattlesnakes (Sistrurus catenatus) from gaining access to the road. I also tested whether ecopassages were effective at allowing Massasaugas to access habitat on both sides of the road. I determined that there was a reduction of Massasaugas on the road post-installation of barrier fencing. Data from various monitoring approaches showed that Massasaugas do indeed use the ecopassages to cross the road. I quantified the long-term effect of mitigation structures on the population viability of Massasaugas. A Population Viability Analysis revealed that post-mitigation construction, the study population has a low probability of extinction, suggesting that mitigation is effective at promoting a sustainable population. Analyzing the effects of road mortality at the population level is crucial to ensure that decision makers are adequately informed of the status of species-at-risk.