These furry engineers play a crucial and largely unrecognized roles in conservation - Eager for Beavers
By Heidi Ridgley
© Tom and Pat Leeson
I always come up here with my heart in my mouth,” says Mary O'Brien, in low tones as we hike up the Tasha Creek trail on a chilly fall day in Fishlake National Forest in south-central Utah. We’re on our way to check out a series of beaver dams, and she’s concerned someone may have killed the resident beavers, causing their dams to break.
We find a narrow spot to jump a stream, flush out some ruffed grouse and pass an older, abandoned dam before she stops short in front of me just as it begins to snow. “You gotta see this,” she says. “Look at those aspen logged right there. Look how the beavers have them all pointed the right way.”
She’s whispering now, explaining how beavers felled all these trees within a month—they weren’t down the last time she hiked up the trail in September—and directed them toward the water, where they will put them to use extending the dam and mending its leaks. “These are the soldiers that died for the cause,” she says of the 60-strong logjam before us.
At first glance, it’s easy to see why people might think a beaver’s busy work is not so beneficial. And yet in places like the arid Southwest where climate change is causing snow in the mountains to melt earlier in the year and droughts to last longer, beavers and their dams are the equivalent of a finger in the dike. They can’t prevent climate change, obviously, but they can take the edge off some of its effects.
Warming temperatures here mean that even at higher altitudes more precipitation falls as rain instead of snow, with storms expected to become more violent. The snow that does fall melts earlier so that instead of a gradual release of water over the summer months, the water gushes from the mountaintops earlier and more intensely. In fact, Utah’s snow melt this year happened 45 days earlier than the historical average. This also means that year-round streams can dry up later in the year, with major consequences for fish.
“These dams act like speed bumps,” says O’Brien, a botanist and Utah forests program manager for the Arizona-based Grand Canyon Trust. “If water hits one, it wells up over the flood plain, slowing down the water. If that dam crashes and burns in the flood, the water will hit another one like stair steps. The rushing water gets slowed at every turn.”
But there are even more benefits to beaver dams: Bank sediment that might get chunked off during a flood or by the heavy hoof of a cow grazing near a stream gets caught and stored behind the dams instead of ending up in a city’s water supply, for instance. Streams rise and stay colder because less sunlight penetrates the deeper water. That’s good for cold-water fish, like cutthroat trout. Water that overflows the banks recharges the aquifers. Stored there, it is returned to the streams, a reserve when the next drought hits.
Despite all this, the beaver’s ecologically beneficial handiwork is an often thankless—even deadly—task. Until recently in Utah—as in many other states—residents could buy a $30 permit and shoot or trap and drown beavers indiscriminately. Estimated at 60 million strong at the time of European settlement, the country’s beaver population dropped to about 100,000 within the next century. Records from early fur trappers show there may have once been as many as 60 to 80 beavers per mile of stream.
“People sometimes get excited to tell me they’ve seen a beaver dam,” says O’Brien. “They have no concept that there should be 15 in that one area. We don’t have the cultural memory of how many beaver dams used to fill a stream because the beavers were mostly gone before white people settled here.” Tasha Creek is an exception with its 17 active beaver dams.
Beavers build dams because on land they are like seals in the sand—slow and vulnerable to their cougar, bear, lynx and coyote predators. “They are just lunch for anything unless they are in the water,” says O’Brien. “Then they are quite fearless.” Beavers build their lodges in deep ponds with entrances accessible only to those who dare to dive below the surface. The trees they chomp down for construction materials in the West—cottonwood, aspen and willow—are adapted to resprout when they fall or burn.
The problem for beavers arises because of another constant in the West: the undying fight over water. “Irrigation companies at the bottom of public lands love getting their water all at once,” says O’Brien. “Then they know how much they have and they can divvy it up for the farmers. But it’s an ecological disaster for the forest above, and it takes away any buffer in a year that doesn’t get much rain.”
Not every landowner is against beavers, however. At the start of our trek, while O’Brien is pointing out Tasha Creek’s dams on a map sprawled across the hood of her car, a man in a truck pulls up to ask if we are headed fishing. “We’re going to look at beaver dams,” says O’Brien. His response: “People blow them up a lot, you know. I have a cabin up here, so I watch things. And I’ll tell you, beavers sure make the fishin’ good. That’s why I like them.” The man, who doesn’t give his name, adds that he needs the water to irrigate his valley. “We have 100 acres of hay, so I need that water, too,” he says. “But it is what it is. Coexist.”
Before driving off, he mentions that he’s starting to see some streams dry up late in the season. But he’s noticed that those that have beavers keep their water. “Up here having beavers works for us,” he says. “But at Niotche Creek [about seven miles north] they blow the dams up all the time—just after we’ve caught some four- or five-pound cutthroat someone will go down there and shoot ’em and blow the dam because they want the water.”
Solutions to the diverging needs of humans and beavers do abound, though—and they come with clever names: “beaver deceivers” and “castor masters” (Castor being the Latin genus for beaver). Deceivers work by allowing water from a beaver-dammed pond—water that is about to back up and flood over a road, for instance—to escape without the beaver ever hearing it trickle away. “The sound of water running drives beavers nuts,” says O’Brien. “They will try to plug up the leaks.” The pond is kept at the desired level by inserting a pipe in the dam that allows the water to release underwater—right under the beaver’s nose.
Castor masters are wire fences with strong posts. They keep beavers from plugging up culverts, which divert water under roads to avoid wash-outs. In this case, beavers hear the water but they can’t get access to the culvert to plug it.
“Both these solutions are cost-effective, sturdy and low-maintenance,” says O’Brien. Experts are still baffled by how to shield crop irrigation ditches, however. “So far, there’s no good way to protect them from beavers,” she admits. “But in these cases, beavers can be live-trapped and moved where they’re wanted.”
With these tools and a new understanding of the healing role beavers play in the environment, a new day is dawning for the 40-plus-pound rodent with the flat-as-plywood tail and the chisel-shaped teeth that never stop growing.
“It’s time we all realized the benefits of beavers,” says Sara Vickerman, director of Defenders’ Oregon field office. “They are true indicators of healthy landscapes and biodiversity. By retaining water, they modify ecosystems to support many other species of plants, insects, fish, birds, amphibians. And now land managers and conservationists are looking to beavers in western states to help mitigate some of our increasingly early spring water woes.”
This is especially true in places with little year-round precipitation, like Utah, where another problem is mucking up the waters: grazing on public lands. That’s actually the main reason we’re hiking up the Tasha Creek trail—not to see beavers (although my fingers are crossed) but so that O’Brien can point out the branches bitten off by elk and cattle. Much of O’Brien’s field work involves measuring the effects grazing is having on Forest Service lands, particularly lands near creeks and streams, in southern and central Utah. “Our data shows that the Dixie and Fishlake national forests are heavily grazed and there is little regeneration of trees and willow into the overstory,” she says.
Rushing ahead on the trail now, she is pointing out an endless sea of woody stubble. “Can you see how this is browsed—and this one and that one?” she calls out. It’s hard to keep up with her while also avoiding the blops of cow pie littering the trail. “That willow is 100 percent browsed. Next season it will have to start from a bud, if it’s still alive, from way down here.” She stops, squats. Her hand hovers only inches off the ground.
“Livestock grazing in the arid Southwest is more a lifestyle than a viable operation,” she says. “It’s marginal land.” Even so, about 84 percent of public land is grazed in the West, O’Brien explains. About 70 percent of U.S. Forest Service land is grazed, like the acreage we’re hiking on today, she says. But the livestock provides only 4 percent of the nation’s beef supply.
Another problem is the ever-increasing elk population. “Elk eat like cows,” says O’Brien. “They like to hang out near the streams and eat the willow, cottonwood and aspen sprouts that come back up after beavers cut down a tree. The combination of elk, cow and beaver is a triple whammy for the willow and trees. But the beaver will take only some willow stems and cut down a big tree because they need the log,” she says. “Cattle come in and eat the resprout before it’s big enough, and then you really have a devastating situation.”
Cottonwood, aspen and willow resprout quickly. An aspen can go from a seedling to six feet tall in three years. Once the leaders—or top branches—are over five feet, cattle can’t reach them. “With grazing they are always getting their heads nipped off,” she says. “If you nip off a leader, the subleaders take over. They get nipped off and in 10 years you end up with a bushy growth no more than two feet tall.”
O’Brien and others concerned with the eroding landscape in Utah spent the last few years working to develop a new beaver management plan, which passed the state wildlife board in January. The new protocol advocates for the live-trapping and relocation of “nuisance” beavers to places that could use their structural engineering and restoration skills. Until now, to remove beavers from “nuisance situations,” old-school state wildlife officials trapped them in underwater nooses and left them to drown.
To get personnel up to speed with live-trapping, Denver-based Sherri Tippie—nicknamed “the beaver whisperer”—will be on hand this year to train state wildlife field staff. A legend in Colorado, Tippie has live-trapped 1,000 beavers for relocation in the last 25 years, only losing two—in a flash flood—and has been bitten only once. But more and more she says she is educating the property owners who call her for relocation help. “They end up realizing there are benefits to having beavers and they decide to live with them,” she says.
Driven by her passion, this is volunteer work for Tippie. “I’m a hairdresser by trade, not a biologist,” she tells me when I reach her by phone in Denver. “But I would rather live trap beavers than do anything else in the world. I love the way they smell, their personality…they are so interesting.”
Back at Tasha Creek, I’m disappointed I don’t have the opportunity to experience Tippie’s joie de Castor canadensis. It’s not yet dusk and the resident beaver family here is still tucked away in their lodge, resting for what appears will be a busy night of log rolling ahead.
Sitting next to me on one of the tree trunks, O’Brien whispers, “Well, my heart isn’t broken. They’re still here.” Certainly, some joy can be found in that.
As a little girl, Senior Editor Heidi Ridgley’s favorite stuffed animal was a beaver she named Thumper.