Beavers and their dams may help amphibians

The dam-building beaver may be an ally in conserving wetland habitat for declining amphibian populations, a University of Alberta study said.

The study identifies the beaver as a valuable "surrogate species" for frog and toad populations, said University of Alberta researchers Cam Stevens and Cindy Paszkowski in the January issue of Biological Conservation.

Surrogate species can indicate changes to the environment or can protect a large number of naturally co-occurring species.

"The concept of surrogate species in conservation planning offers simple, ecologically-based solutions to help conserve and manage ecosystems," said Paszkowski, a biological sciences professor at the university.

Beaver ponds appear to offer suitable breeding habitats for amphibians because of their warm, well-oxygenated water, which enhances development and growth rates of frog and toad larvae, she said. The ponds may be less inviting to predators because dams usually are on small streams where winterkill conditions are common.

Beavers may be useful as a surrogate species in helping to conserve frogs and toads in remote parts of western North America.

"The challenge will be to promote modest levels of beaver activity even where conflicts with human interests might occur," Stevens noted.

Copyright 2007 by United Press International