Science. Beavers could help California fight effects of drought.

By Samantha Clark, Santa Cruz Sentinel


Beavers could help California fight effects of drought.

By Samantha Clark, Santa Cruz Sentinel.

LOS GATOS, Calif. — Three punishing years of drought have parched California streams, rivers and wetlands.

One animal has the potential to restore these dry landscapes.

With their industrial-strength buck teeth and flat tails, beavers and their dams offer a defense against drought. The rodents are known as ecosystem engineers. And they once populated most of California until fur traders nearly wiped them out in the 19th century.

This state has lost more of its wetlands than all other states, and beavers can rebuild those wetlands,” said Rick Lanman of the Institute for Historical Ecology in Los Altos.Knowing that it is native should help guide restoration efforts.

Beaver dams benefit the environment in ways that humans can’t easily copy. They turn land into a sponge for water. Their gnawing and nesting promotes richer soil and slows down water, improving imperiled fish habitat. Their dams raise water tables, nourishing shrubbery alongside streams that stabilize eroding banks, and add habitat for birds and deer. They also help the endangered California red-legged frog.

Because beavers are so good at recharging ground water, they can make streams flow when they would otherwise run dry such as during the summer months.

After beavers move to a new area, at night, they drag a tree across a shallow stream to start a dam. They carry rocks and mud with their paws and branches with their big incisors. Water in these beaver ponds would otherwise flow away. So it’s no surprise that thirsty Western states are turning to the beavers with open arms.

There’s a growing interest in using beaver as a habitat restoration tool,” said Michael M. Pollock, an ecosystems analyst with the National Oceanic and Atmospheric Administration in Seattle.They create good wetland habitat much more cheaply than other restoration methods.

He added, “Beaver ponds are beneficial because they also create a lot of wetland that provides a lot of food for fish."

Beavers can also help reverse the rising temperatures of water, which can harm fish. The deep pools created by their dams have cooler water at the bottom.