Meeting Abstract
Roadways kill tens of thousands of amphibians annually in the United States and this mortality is likely to increase as over 13,000 additional miles are constructed annually. Roadways depress amphibian population sizes, disrupt connectivity, and degrade habitat. Barriers and ecopassages are increasingly being implemented to mitigate roadway impacts. Barriers limit access to roadways and may direct animals toward ecopassages, which are corridors designed to conduct animals safely over or under the roadway. The effectiveness of these mitigation measures remains poorly studied. The Nelsonville bypass, completed in 2013, bisected the largest tract of continuous forest in Ohio, including wetlands and associated amphibian migration routes. The Ohio Department of Transportation installed mitigation measures and views this as their flagship effort, upon which future projects will be based. We quantified levels of roadway mortality, ecopassage use, and amphibian populations, in order to assess the effectiveness of a barrier-ecopassage system. We monitored wildlife deaths along a 2.6km stretch of two-lane highway, used camera traps in two ecopassages, examined drift fence effectiveness, and surveyed surrounding habitat to obtain population estimates. In the spring of 2015, 6,311 amphibians were found dead along the roadway, two individuals were seen using the ecopassages successfully, and 104 individuals were trapped trying to circumvent the drift fence. Preliminary population estimates and growth models indicate populations may not be large enough to sustain additive mortality. This suggests that the barrier-ecopassage system in place is not effective. Future work will evaluate alternatives to the current mitigation design.
