“Fish Fervor Destroys Beavers,” shouts a piece titled “Wisconsin’s War on Nature” in Beaversprite magazine: “Since 1985 the Wisconsin Dept. of Natural Resources (WDNR) has waged a successful campaign to wipe out 70 percent of the state’s beavers for the declared benefit of trout fishermen.” (WDNR has eliminated no such percentage, and it has “wiped out” no system.)
Beaversprite goes on to assert that “Beaver co-evolved with salmonids making improbable an essentially negative relationship between these organisms.” Managers hear this claim constantly.
Willging’s response: “While beaver and brook trout may have occurred in the same North American regions for millennia, it does not mean trout have any evolutionary adaptations to survive in warmwater environments or to overcome the blockage of a beaver-dammed stream. Also, coldwater stream ecosystems are not just about brook trout, they can be very complex systems rich in species diversity. . . . They often provide refuge for many species from higher temperatures, flooding, and predators. They provide habitat for many unique species, including insects, mollusks, crustaceans, amphibians, and fish. Unfortunately, these coldwater systems are declining in the United States, and in many areas the sustainability of native brook trout populations is in jeopardy.”
In the Duluth, Minnesota, area, a group called Advocates for the Knife River Watershed is fighting beaver control on the Knife system, citing all manner of inapplicable studies from the far West and making such preposterous claims as “beaver have been totally eradicated in the whole Knife River valley, over 200 square miles.”
“There are a lot of people in our organization who really value the beaver ponds as something that attracts wildlife and increases biodiversity,” the group’s chair, Corlis West, told the Lake County News Chronicle. “Not just beavers, but for moose and mink and waterfowl and frogs and turtles.”
“They [beaver ponds] provide special habitat,” added retired University of Minnesota Duluth geology professor John Green. “They’re wildlife magnets for breeding and migrating birds. All kinds of wildlife like them, and people enjoy those.”
West and Green are not wrong. But even with beaver control, there is more beaver-created wildlife habitat on the Knife system than before Europeans arrived and one hell of a lot fewer coaster brook trout moving up from Lake Superior. The Knife is one of the state’s most important steelhead streams; and, while beaver control benefits native coasters, most of the work is aimed at opening blocked steelhead spawning access. Advocates for the Knife River Watershed charge that the DNR and Wildlife Services are sacrificing a native species for an alien. Does it have a point? No. Because no one is “sacrificing” anything. Beavers are still way overpopulated in the watershed. And while steelhead are indeed alien to lake and tribs, they’re an important, self-sustaining resource adored by anglers and a boon to the state’s economy. All the noise has prompted DNR to back off a bit, but some beaver control continues. Duluth Area Fisheries Supervisor Deserae Hendrickson offers this: “Funding is extremely limited, so we’ve had to target very specific mainstem areas in the Knife and Blackhoof–Nemadji watersheds that are critical for migratory fish.”
SALMONIDS BENEFIT FROM BEAVERS IN MUCH OF THE WEST; but beaver irruptions are nuking lots of coldwater habitat even there.
Consider the situation in Nevada. To save imperiled trout, the Department of Wildlife was taking out a few beavers until the 1990s, when the Humane Society of the United States whipped up the public to the point that politicians shut down the program. The state hasn’t been willing to step back into that fray since. But eight years ago, Nevada committed to restoring native trout in historic ranges—primarily federally threatened Lahontan cutthroat but also Bonneville and westslope cutthroat, bull trout, and redbands. “When that push started,” reports the Department of Wildlife’s former conservation educator, Kim Toulouse, “we discovered that many single-order streams were infested with heavy beaver populations. Extremely high numbers of beaver dams led to loss of gene flow and precluded the ability of fish to move up and down these systems. Additionally, fish had difficulty finding suitable spawning grounds due to heavy siltation caused by the dams. The loss of riparian habitat led to erosion, more siltation, less shade, higher water temperatures, loss of native riparian vegetation, and establishment of noxious invasive plants. In some cases, increased sunlight has allowed establishment of nonnative submerged vegetation like Eurasian milfoil.”
On Nevada’s Truckee River, the U.S. Fish and Wildlife Service is trying to recover salmon-size Lahontans that migrate up from Pyramid Lake to spawn. Toulouse, who lives within a half mile of the Truckee, fishes it regularly. It’s overrun with beavers—bank dwellers because the mainstem is too big for dams. “On a number of reaches, beavers have decimated the entire cottonwood population on both banks,” he says. “That has removed shade and insect populations, primarily terrestrials. Replacing the cottonwoods have been mainly [nonnative] invasives like tall whitetop. It’s very difficult to treat. It takes over everything, and it releases a toxin that prevents the spread of natives.”
On California’s Silver King Creek, in the Carson-Iceberg Wilderness of the High Sierras, the Paiute cutthroat was being hybridized off the planet by alien rainbows. The only tool to save this rarest of North American salmonids from certain extinction was rotenone. This organic piscicide, applied at 50 parts per billion, is so short-lived that it can lose toxicity in an hour. It has never permanently affected an aquatic ecosystem except to restore it.
The court battles that blocked Paiute recovery for a decade provide more evidence that fish don’t count as wildlife for most of the public. These lawsuits were based entirely on imagined, fictional dangers of rotenone. Rotenone, argued a host of individuals and environmental groups, would kill everything in or near the stream, including beavers. They further alleged that rotenone’s single purpose everywhere it is deployed is to benefit “recreationalists,” who, in this case, supposedly couldn’t wait to run 15 miles uphill into wilderness to catch eight-inch trout.
Providing pro bono representation to these litigants was the Western Environmental Law Center, which wrongly proclaimed in a press release (yet to be retracted) that rotenone “does not just kill the fish in the water but the entire ecosystem, including turtles, snakes, frogs, birds, terrestrials, insects and other animals that live in or drink from the poisoned water.” (Rotenone harms nothing with lungs. Even most aquatic insects survive, and the few that don’t are replaced in weeks.)
Paiute recovery would have failed had not managers of the California Department of Fish and Wildlife, the U.S. Fish and Wildlife Service, and the U.S. Forest Service facilitated uninterrupted flow of rotenone by removing beaver dams. A few days after the 2015 treatment, the beavers, which hadn’t noticed the rotenone, rebuilt the dams. That was fine with the recovery team because of Silver King Creek’s high gradient.
But beavers devastated Silver King tributary Four-Mile Canyon Creek, a vital Paiute sanctuary. “The dams caused a lot of erosion up there,” remarks California fisheries biologist Bill Somer. “Trout Unlimited brought in volunteers and successfully rerouted the stream. The biggest problem I see with beavers is that after they move into an area and eliminate forage, they abandon their dams. When these dams, which have captured sediment, blow out, there’s erosion. I’ve seen that in a lot of places.”
BEAVERS ARE LIKE RED WINE. Because the medical profession affirms that one glass a day is heart healthy, one should not conclude that 40 glasses a day are 40 times better, or better at all.
Wildlife advocates need to keep two different thoughts about beavers in their heads simultaneously. Beavers in moderation can be good for coldwater species. What’s bad for coldwater species is not beavers; it is too many beavers—unnatural proliferations caused by human activity, such as clear-cutting and wolf eradication. “Letting nature take its course” doesn’t mean sitting on our hands after we’ve disrupted natural balances.
Aldo Leopold was a trout fisherman. Were he alive today, in my opinion, he’d advocate for beaver recovery where needed and for beaver control where overpopulations are eliminating coldwater habitat.
It’s unlikely that managers will ever be able to restore more than a tiny fraction of trout streams destroyed by beavers. But, as Leopold wrote in a 1946 letter to his friend Bill Vogt: “That [a] situation appears hopeless should not prevent us from doing our best.”
Ted Williams’s environmental writings enjoy national acclaim, and keep the bad guys sometimes honest and looking over their shoulders.