Effective Placement of Road Mitigation Using Lessons Learned from Turtle Crossing Signs in Ontario

In landscapes inundated with roads, wildlife is likely to negatively interact with vehicles during its lifetime. Wildlife crossing signs are easily deployed, cost-effective, and meant to encourage wildlife-friendly driving practices in hopes of reducing wildlife-vehicle collisions (WVCs) along roads. Here we use the placement of turtle crossing signs as a case study to provide recommendations for informed placement of mitigation structures across regional landscapes in Ontario and elsewhere. We collected relevant information (design, theft, and location) from 369 turtle crossing signs placed along roads. We then compiled turtle-vehicle collision data from various sources to statistically analyze where they occur in relation to habitat and road type. We also compared the locations of turtle crossing signs to validated hotspots, which was equivalent to 19,000 km of road in Southern Ontario. We found that at least 27% of signs were stolen and at least 10 different design types exist for crossing signs in Ontario. Thirteen percent of signs were not located at validated hotspots, and turtle-vehicle collisions occurred most often on paved highways and county roads. We conclude that a road mitigation strategy should accurately inventory where structures are located and monitor their effectiveness. Structures should be selectively placed using the best available information, such as metapopulation science and WVC data, especially in regions heavily fragmented by roads. In multi-jurisdictional regions, an effective strategy should also consider regional coordination that focuses on standardized sign design and information sharing in an adaptive approach.