📖 Wetland Road Culverts as Amphibian Conduits. An Evaluation of Steel Culverts as Transit Corridors for Wetland Amphibians and Small Mammals.

Linear developments, such as roads, are recognized as major contributors to wetland fragmentation. Studies have shown that the barrier effect of roads result in inbreeding among wetland species and reduced genetic diversity. For amphibian species, heightened risk of local extinction due to population dynamics, and decreases in the ability of species to re-colonize otherwise suitable habitat have been cited. This publication examines strategies adopted to mitigate fragmentation effects on sensitive wetland habitats. Corrugated steel culverts are evaluated for their effectiveness as transit corridors for amphibians and small mammals at Vancouver Island locations. Tracks of several species are recorded and analyzed for occurrences over time. Recommendations are made for improved monitoring of amphibians and small mammals near roads, and for enhancing the performance of culverts as transit corridors beneath roads. Comparative trials compare preferences of the Rough-skinned Newt (Taricha granulosa) for corrugated steel culvert treatments. Results of the trials show amphibian preferences for the amount of moisture, the amount of light, and substrates used within steel culverts.