Helping turtles cross the road: Improving culvert design and monitoring
Road mortality contributes significantly to the population decline of many turtle species. Roadside drainage culverts can act as safe movement conduits, offering turtles a safe means to transverse busy roadways. My research explored two areas relating to herpetofauna use of culverts: 1) the creation of turtle-friendly beaver exclusion devices, and 2) the development of best practices for the use of cameras in monitoring herpetofaunal use of mitigation infrastructure. A literature review was conducted to determine if a turtle-friendly beaver exclusion device currently exists that allows turtles to pass through the device in order to access the culvert inlet. Results show that very few devices have been designed to specifically accommodate turtles, and though various modifications exist that can be used with existing beaver exclusion devices to make them more turtle friendly, the effectiveness of these are largely unknown. Without providing access through the device to the culvert inlet, turtles are unable to make use of culverts as movement conduits. Suggestions were made on which beaver exclusion devices could be used in combination with these modifications, which is the first known attempt at modifying multiple existing beaver exclusion devices to accommodate them specifically for turtles. A second literature review was conducted addressing the second research area, to determine if a standardized protocol or list of best practices has been developed for camera-based monitoring of herpetofauna at road mortality mitigation infrastructure. The understanding of cameras for this application is limited compared to mammals, largely because cold-blooded herpetofauna have a smaller thermal footprint and are not captured as often by cameras as a result, making results unreliable or inconsistent. Following best practices can help consolidate camera study methodologies, possibly improving the effectiveness of camera traps. Reliable monitoring studies can help determine the use and effectiveness of various mitigation structures, which can be implemented in future road development projects. Results indicated that a protocol does not exist, and a list of recommendations and best practices identified from the literature was developed. These recommendations act as a benchmark, and can be built upon in future studies, until standardized protocols can be developed.