The Potential of the Hose-bridge to Mitigate Snake Mortality on Low Volume Roadways
Indiana State University
Stephen J. Mullin
Stephen F. Austin State University
Various structures have been integrated into roadways such that the road itself does not impede wildlife movements between adjacent habitats. Where traffic volume is low, the costs of installing and maintaining such structures are typically prohibitive. We tested the efficacy of a hose-bridge deployed temporarily on a State Park road that allowed the passage of cars over it, and small wildlife species to cross through it. We predicted that, during the 4.5-week period of peak migratory movement, road-based mortality of Dekay’s Brownsnakes (Storeria dekayi) would be less at the site having the hose-bridge, when compared to a similar section of road without a hose-bridge (control). We erected drift fences at both sites to guide snakes to each section of road and collected snakes that successfully crossed the road with arrays of cover objects and pitfall and funnel traps. The speed limit on the road varied from 32–48 kph, but cars passing over the hose-bridge slowed to ≤8 kph. Snake mortality at the hose-bridge site was reduced compared to the control site. Mean mortality at both sites was lower than in previous years, which might be attributable to reduced vehicle speed or increased motorist awareness of migrating wildlife. Compared to the pattern recorded in the preceding four years, the hose-bridge and accompanying signage effectively decreased the road-based mortality of Storeria dekayi during their 2014 and 2015 Autumn migrations.