A group of West Marin land managers and conservationists is exploring the reintroduction of beavers to buffer the impacts of drought, increase biodiversity and improve salmon habitat.
A steering committee spearheaded by the Occidental Arts and Ecology Center and made up of representatives of the Marin Resource Conservation District, Marin Water, the Salmon Protection and Watershed Network and the Environmental Action Committee hopes to simulate a beaver dam this summer with funding from the United States Fish and Wildlife Service. The ecology center received a grant for a feasibility assessment in 2019, and the group is now summarizing its research in advance of sending its report to Fish and Wildlife.
Brock Dolman, a wildlife biologist and a co-founder of the ecology center, said the effort involves landowner and community outreach. “On behalf of the community overall, as well as the beavers themselves, we want to have a thoughtful and participatory process,” he said.
Beavers are ecosystem engineers, changing the landscape more than any other non-human animal in North America. According to Mr. Dolman, they are a cost-effective tool for restoring meadows, rangelands and endangered salmonid habitat; their dams filter and purify water, enrich the soil and create habitat for dozens of species.
Marin is the only county north of the San Francisco Bay without beavers, which were present prior to European arrival but were hunted to near extinction. Without beaver dams, huge areas of land were left with less water. Now, many streams in Marin are eroded, incised and damaged, causing the surrounding water table to drop.
Eric Ettlinger, an aquatic ecologist for Marin Water who sits on the steering committee, said when the water table falls too low to feed plant roots, native vegetation dies off and a barren, arid landscape results. By increasing water surface area, absorbing energy from floods, and increasing resiliency to fire, beaver dams also help buffer climate extremes.
“Raising the water table and storing water in a natural way should be very appealing to the community” as California wrestles with drought and climate change, Mr. Ettlinger said. Expanding the green area surrounding a stream creates a fire break, while higher groundwater levels increase water supply and decrease fire risk. “This is a benefit people are seeing in many places that have beavers,” he said.
California attempted a beaver reintroduction to the Point Reyes Peninsula in the 1940s, but the transplant didn’t take. And although Fish and Wildlife recognizes the benefits that beavers can bring, it operates under a 1980s rule that prohibits beaver reintroduction. Kate Lundquist, the co-director of the Occidental Arts and Ecology Center’s WATER Institute who is leading the beaver campaign, said questions around liability and management have not been resolved in California, and current regulations only allow property owners to remove dams and kill beavers. Introducing beavers is illegal.
“If people are really interested, they need to reach out to [Fish and Wildlife] to say they want to support a pilot,” Ms. Lundquist said. “A diverse group of stakeholders with agency support would [need to] show broad interest and make a good case for a pilot program.”
Ms. Lundquist and others involved in the effort have visited sites in the Walker Creek, Pine Gulch, Olema and Lagunitas Creek watersheds to understand each habitat and how beavers could fit in. The feasibility study is making use of a geographic information system-based tool developed at Utah State University that is widely used to guide the placement of beavers across the country.
Some rangeland managers in the arid West have sustained their operations in large part due to grazing regime changes and beaver introductions. In November, the Marin Resource Conservation District hosted a panel with three ranchers from California and Nevada who have experience with beavers, and the group is interested in finding funding for several West Marin ranchers to pilot a beaver dam analog program.
“All the good things beavers do are of interest to everybody,” said rancher Sally Gale, who chairs the R.C.D.
Jon Griggs, a cattle rancher from Elko, Nev., said when beavers first showed up on his land, he thought they would undo all his work. But he couldn’t have been more wrong: The beavers created green riparian zones and made water available for stock year-round. “Increasingly there is recognition that beavers are beneficial when you’re working with bovines,” he said.
But beavers can also be perceived as a nuisance, Ms. Gale said, and landowners want predictability and control over their water. Because beavers cover a lot of territory, landowners upstream and downstream would have to be engaged.
“[Beavers] don’t pay much attention to property lines,” Mr. Dolman said.
A key part of the feasibility assessment involves “understanding the demographics of the land use and ownership, from federal to state to private,” he added.