The recovery of beavers may have beneficial consequences for amphibians because beaver dams can create the unique habitats that amphibians need.

“Beaver-dammed wetlands support more of the amphibian species that need a long time to develop in water as larvae before they are able to live on land as adults,” said Jonah Piovia-Scott, assistant professor in the School of Biological Sciences and one of the authors of a paper published in the journal Freshwater Biology.

The study took place in the Gifford Pinchot National Forest of the Cascade Range, where four WSU Vancouver researchers identified 49 study sites either with or without beaver dams and found the beaver-dammed sites were 2.7 times higher in amphibian species richness than the undammed sites.

Certain types of amphibians, particularly those that develop more slowly, such as red-legged frogs and northwestern salamanders, were detected almost exclusively in dammed sites.

Beaver dam.
A beaver dam in the Cascade range. Photo by John Romansic

Beavers, once abundant in the Pacific Northwest, were hunted nearly to extinction in the 19th century. But, in an effort to improve wildlife habitat and mitigate the effects of climate extremes, some land managers are relocating beavers into places they occupied in the past, and beavers’ numbers are slowly recovering, which is also benefiting amphibians, according to the study.

Red-legged frogs and northwestern salamanders are also the species most threatened by climate change, which is projected to bring drier summer conditions to streams and wetlands in the Cascade Range. By expanding existing ponds and increasing the time before they dry up, beaver dams are allowing such species more time to reproduce and develop.

“Beavers may be a key component of ecological resilience to climate change in these ecosystems,” Piovia-Scott said.

In addition to Piovia-Scott, the authors of the study are Kevan Moffett, assistant professor in the School of the Environment; John Romansic, former postdoctoral scholar in the School of Biological Sciences; and Nicolette Nelson, former graduate student in the School of Biological Sciences.

Top image: A beaver swimming in a lake (photo by Braedon Mcleod).

By Sylvia Lindman, WSU Vancouver, for WSU News