A new California policy highlights the importance of beavers, and offers protections

There used to be hundreds of millions of beavers in North America. But that was before the launch of the European-American fur trade began in the 1600s, which decimated the species. 

Today, ecohydrologist Emily Fairfax said about 10% of that population remains. Their absence, she added, has had a big impact on the continent. She describes the animal as an “ecosystem engineer” given their unique ability to create wetland habitat. 

“When you take all those beavers out, and you take them out really rapidly like happened during the fur trade … all of that natural infrastructure starts to degrade and wash away,” said Fairfax, who studies beavers with California State University Channel Islands. “There's just massive land-use changes that resulted in things like drying of landscape, serious aridification, overgrown forests and a lot of fire.”

California officials have more recently paid close attention to how beavers’ unique abilities can help combat climate change impacts. Last year, the state launched its new Beaver Restoration Program, which sees beavers as a nature-based aid for boosting biodiversity and mitigating wildfire risk. And now, a new policy from California’s Department of Fish and Wildlife calls beavers a “keystone species,” highlighting their important role in upkeeping ecosystems. 

“Ecologically speaking, a keystone species is a species that plays a critical role in maintaining the diversity and health of an ecosystem, such that the removal of the species results in a cascade of impacts to the ecosystem,” said Valerie Cook, California’s beaver restoration manager, in an emailed statement. 

In the statement, Cook said beavers boost biodiversity and bring flowing waters to streams that would otherwise dry up. They also create important wetland and wet meadow habitats.  

Fairfax said beavers can help reduce the risks of extreme flooding, drought and even wildfire. 

“When beavers move into landscapes, they are absolutely the expert at slowing the water down and keeping the water on the landscape longer,” she said. “As we shift from having most of our water come as snow to most of it coming as rain, that just increases our need to keep it up in the mountains for longer so that we do have access to it during summer when we need it.”

In addition to recognizing beavers’ important ecological role, the policy also encourages their relocation and reintroduction to historic homelands over lethal removal. In the statement, Cook said conflict between beavers and landowners typically arises when the animal damages property, crops or land. 

As one example, Fairfax said beavers have occasionally built their dams in culverts.

“Whoever is on either side of that culvert suddenly has flooding issues, and culverts usually go under roads, so that means your road's flooded,” she said. 

A dam built by beavers in Atascadero, Calif.Emily Fairfax

Fairfax said the new policy encourages beaver relocation and reintroduction at a scale that hasn’t been seen in California since the 1940s. The Beaver Restoration Program, which received about $3 million from the state budget, will take the lead on this management. It’s a positive for beavers and their environments, she said, to opt for those options before lethal removal whenever possible. 

But while a beaver’s impact on its environment is huge, Fairfax said researchers still aren’t exactly sure what this impact looked like before the fur trade shrunk their population size. 

A screenshot from a game camera shows a California beaver climbing along a river bank.Emily Fairfax

“Because beavers have been gone for so long in a lot of these places, we don't always have a good understanding of what role they were playing in controlling those rivers and streams and ecosystems,” she said. 

That’s part of the next question for researchers like Fairfax: Before the fur trade, exactly where did beavers live and what did the full scope of their impact look like? Answering those questions could help states seeking to better manage beaver populations, she said. 

But their usefulness is undoubtable. In the last 200 years, Fairfax said the American West has lost anywhere between 50% to 90% of its wetlands. Beavers are key to bringing them back, which comes with a host of other benefits. 

“You remove the beaver from its wetland ecosystem, that can cause collapse of that ecosystem,” she said. “So, taking the bottom out of the Jenga tower, the whole thing falls over.”