Evaluating Reptile and Amphibian Passage Gates using Remote Camera Traps

The Asian Carp bypass barrier in northeastern Illinois was built to prevent the invasive from entering the Great Lakes during high floods but has since resulted in habitat fragmentation. A year after the terrestrial barrier installation, wildlife passage gates were installed to facilitate movement of native organisms, including the state endangered Blanding's Turtle (Emydoidea blandingii). To determine the effectiveness of gates, we conducted 45 visual encounter surveys along the barrier and placed wildlife cameras on 14 of 20 gates. We found ten reptile species along the barrier and photographed nine using the gates. Common Gartersnakes (Thamnophis sirtalis), Northern Water Snakes (Nerodia sipedon), and Painted Turtles (Chrysemys picta) were commonly found along the barrier and were photographed using the gates frequently. Three Blanding's Turtles were found along the barrier, but none used the monitored gates. We found five amphibian species along the barrier and photographed three species using the gates. The cameras also documented abundant mammalian mesopredators, and our visual surveys found 34 depredated turtle nests. The barrier may act as a conduit for nest predators to search along. Adult reptiles typically used gates during daylight hours whereas potential mammalian predators used gates at night. Overall, the gates were somewhat effective at facilitating movement of most reptile species present other than the Blanding's Turtles.