A new(ish) article (Feb 2008 ) out in Herpetological Conservation and Biology (PDF) finds that a staggering amount of amphibians in the Midwest are roadkill. The total list of all the vertebrate things killed on roads is just depressing as hell. (The list is too long to reproduce here.)
While lots of things died on the roads, nearly 95% of the roadkill appears to be amphibians. Given the threatened status of amphibians worldwide, and the increasing paving of the planet, this is disturbing.
From their discussion:
“Our results emphasize that road-kill may be a significant factor in the overall decline of amphibian and reptile populations, particularly frogs and other amphibians. Consider our results and those of two other studies: Ashley and Robinson (1996) plus Smith and Dodd (2003). Collectively, these three studies document 42,502 dead amphibians and reptiles across four routes which span a total of only 11.5 km of road. The total number of survey days was 488, which translates into a mean of roughly 7.6 dead amphibians and reptiles/km/day.”
I currently commute on roads through a lot of wetlands, and regularly see squashed turtles. I wonder how many other types of flattened fauna I am missing.
The authors emphasize that road-kill should be considered a major risk when evaluating endangered/threatened species recovery plans. Additionally, routing away from wetlands, or putting in alternate routes for wildlife (animal underpasses) should be considered.
Sigh. Poor frogs and salamanders.