Every now and then a beaver report emerges that is SO exactly what we need right now and SUCH very good news that I am torn between waving my beaver pompoms and cheering madly in the bleachers and stamping my foot in anger shouting SEE? IS THIS ENOUGH? Do you believe me now? Will you stop killing them now?
For the sake of brevity I’ll just do the first for now.
Beaver Dams Help Wildfire-Ravaged Ecosystems Recover Long after Flames Subside
Dams mop up debris that would otherwise kill fish and other downstream wildlife, new observations suggest
Oregon endured the third-largest wildfire in its recorded history last summer. The Bootleg Fire tore through the Upper Klamath Basin, an ecologically sensitive area that is home to multiple threatened and endangered species including the northern spotted owl and two fish—the koptu and c’waam (shortnose sucker and Lost River sucker)—that are culturally vital to the area’s Klamath Tribes. The fire left behind a charred landscape more than twice the size of New York City.
After the local fire season ended in autumn, Bill Tinniswood, a fisheries biologist with the Oregon Department of Fish and Wildlife, went out to survey the damage. Ash from the fire, which burned for more than a month, had clogged formerly pristine tributaries and turned them into black slurries. Thriving trout populations had disappeared, presumably choked to death by waterborne debris particles that deprived the fish of oxygen. “I was in total shock,” Tinniswood said. “It just looked like devastation.”
Then Tinniswood and his team stumbled upon something even more surprising, and somewhat encouraging: roughly five acres of pristine greenery amid an otherwise burned-out area along Dixon Creek, a tributary in the Sprague River watershed. At the center were roughly eight active beaver dams. But this was more than a refuge from fire, which hundreds of beaver dams are known to have afforded to other riparian areas. Whereas fish seemed to have disappeared upstream of the Dixon Creek dam site, the downstream water was crystal clear—and trout were thriving as though the fire had never happened. The dams and ponds appeared to have altered the hydrology of the landscape around them, Tinniswood says. The beavers had effectively built something like a water treatment plant that staved off fire-related contamination.
Did you read that? Read that again. Read it to everyone you know. Everyone who had to evacuate in the Caldor fire and the Glass fire. Everyone who thinks beavers and their dams are a nuisance. \
Similar dam-driven refuges have been documented from Colorado to California, Idaho to Wyoming. Now, scientists are discovering that these green sanctuaries are part of a larger story of how beaver dams contribute to fire resilience. Along with deterring the flames themselves, beaver dams and ponds also function as filters for ash and other fire-produced pollutants that enter waterways—thus maintaining water quality for fish, other aquatic animals, and humans—emerging evidence suggests.
I can’t help it. I literally can’t stop myself. What the fuck does it take to convince you people? You kill the beavers, concrete the rivers, you boil the planet, you burn the earth to the ground, but beavers make it look like NOTHING EVER HAPPENED. Beavers fix what you break, Every time. Every where.
Tinniswood isn’t the first to observe that beaver dams protect streams from the toxic effects of postfire runoff. In the past several years, as climate change has ramped up wildfire frequency and intensity throughout the western U.S., similar accounts have come in after fires across the region. These range from the 2018 Sharps Fire in Idaho to the 2020 Lefthand Canyon and Cameron Peak fires in Colorado. Ecohydrologist Emily Fairfax of California State University Channel Islands, who personally made such observations in Colorado, says such findings support efforts to conserve and reintroduce beavers in the West, and to establish human-made structures that mimic beaver dams—a growing movement in riparian restoration.
Well sure, beaver dams save fish and protect wildlife and reduce fires and store water and fight climate change and protect biodiversity but other than that. really, what good are they?
Beaver dams and ponds filter out sediment by slowing the rate at which water flows, says researcher Sarah Koenigsberg at the Beaver Coalition, an Oregon-based nonprofit organization that promotes conservation. When water lazily drifts through a beaver pond rather than rushing in a torrent down a narrow channel, suspended sediment has time to settle on the bottom where it poses less risk to fish and other aquatic animals. “You can almost think of it like a coffee filter,” Koenigsberg said.
Koenigsberg observed these effects firsthand in the aftermath of the 2020 Almeda Fire, which destroyed two towns along the Bear Creek watershed in southern Oregon. In one burned portion of the creek, sediment from the fire had formed a deep sludge just above a beaver dam. “That’s homes, that’s tires, that’s asbestos,” Koenigsberg says. But below the dam, the water was crystal clear.
Well what if we build the dams ourselves? Can’t we just install temporary dams like that paper I wrote about Caroline Nash a couple days ago? Won’t that fix the runoff problem without all those icky beavers?
After the 2018 South Sugarloaf Fire scorched 230,000 acres in northeastern Nevada, the U.S. Forest Service installed BDAs in anticipation of postfire runoff. That same year in Idaho, a coalition of government agencies and nonprofit organizations collaborated to build 100 BDAs along a five-mile stretch of Baugh Creek, in part to prevent runoff from infiltrating the aquatic ecosystem after a fire there.
BDAs are certainly not a replacement for beavers, notes Joe Wheaton, a fluvial geomorphologist at Utah State University and one of the scientists who developed the analogues. They are “leaky sieves” that should be thought of only as a temporary solution, he adds. “If they’re not maintained, they don’t have the same benefit.” Without beavers around to do this work, the structures will eventually wash away.
The hope is that by creating a riparian area that more closely resembles beaver habitat, BDAs will attract the animals to the area or allow them to be readily introduced, the Klamath Tribes’ Gonyaw says. The Tribes recently received $20,000 from the Oregon Conservation and Recreation Fund to initiate such a project in the spring. The first step will involve planting native trees for future beavers to gnaw on. Then, construction of BDAs and lodgelike structures will begin. Gonyaw estimates the full project will be completed in three to five years. “It’s a work in progress,” he says. And it’s a step toward a riparian landscape that more closely resembles the one that existed before the fur trade, he adds—one that evolved alongside wildfire, and was resilient to it.
The hope is that if you BDA your way to readiness and plant some willow in these strangled streams beavers will come and do it better eventually. Because beavers are better. They just are,
Isobel Whitcomb from Portland is the author of the article and I think we have a new best friend. So beavers prevent fires and the dangerous runoff fires bring? What’s next?
