[by Ted Williams]
SO FREQUENTLY DO WILDLIFE ADVOCATES QUOTE ALDO LEOPOLD’S ESSAY “THINKING LIKE A MOUNTAIN” THAT IT HAS BECOME A CLICHÉ.
So I’ll condense as much as possible: Leopold describes a mountain, rendered wolfless by humans, on which all edible vegetation has been “browsed, first to anaemic desuetude, and then to death . . . every edible tree defoliated to the height of a saddlehorn” to the point that “it looks as if someone had given God new pruning shears, and forbidden Him all other exercise.” He suggests that, “as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer.”
But the broader lesson is lost on most of the public. A case in point is its inability to accept biological realities of beaver overpopulation.
The causes of ecological damage by deer and beaver are identical. Wolves, the major predator of both species, have been extirpated or severely reduced in most deer and beaver range. Heavy logging in deer and beaver range has replaced poorhabitat old growth with deer and beaver candy such as aspen and willow.
Photo by Len Harris
Beavers in natural abundance have usually been good for native ecosystems, trout included. In much of the Pacific Northwest, beavers are depleted, and managers are rightly attempting recovery.
This from Bill Bakke, founder of the Oregon-based Native Fish Society: “Beavers got sacked in the 1840s. Mainly it was the English trying to keep Americans from coming here for pelts. Hudson’s Bay Company sent out work parties to exterminate beavers. They haven’t fully recovered, and they’re still being trapped. We’re trying to get the agencies to recognize that beavers enhance both fish and water quality.”
“God bless beavers and their industrious nature,” writes Trout Unlimited’s Idaho-based Chris Hunt in Hatch magazine. “They make habitat for the fish we love, and opportunities to catch them.”
“Beavers .. . create reservoirs of cool water that salmon need to survive,” report the Northwest Treaty Tribes of western Washington State in a news release titled “Beavers Relocated to Improve Salmon Habitat.”
Such assertions are accurate in Oregon, Idaho, and Washington, at least on most high-gradient streams. But when they’re cited as alleged evidence that all beaver populations are great for all species in all states, they’re flat wrong; and they hurt the cause of native ecosystems. Do a Google search for beavers and trout, and almost all you’ll find are effusions about the alleged value of beavers everywhere and excoriations of fisheries managers who attempt to modestly control gross irruptions.
For years, the only leg-hold traps legal in my state of Massachusetts were water sets that drowned beavers. But in 1996, voters approved a ballot initiative outlawing all body-gripping traps, water sets included. By the early 21st century, our beaver population had quadrupled.
Since then, the state’s beavers have declined because they’ve stripped away so much forage, but they’re still overpopulated. Benthic organisms, such as aquatic salamanders, mussels, crayfish, insects, and hibernating frogs and turtles (some imperiled) die when dams are ripped out by flooded property owners. These days, animal-control agents are called in to “humanely” remove nuisance beavers.
After the beavers are terrorized all night in live-capture traps, they’re clubbed to death and usually landfilled. We’ve converted a resource to a pest.
Now, in what were some of my favorite wild-trout streams, where I used to stand on clean gravel, catching brookies, I slog through scat-festooned silt, catching fallfish or nothing.
BUT BEAVER BLIGHT IN THE EAST IS MILD COMPARED TO THAT IN THE MIDWEST. Angler/photographer Len Harris of Richland Center, Wisconsin, describes the pre-hangover high that comes with the discovery of a new beaver pond: “It’s smile-producing at first because of bigger trout. But the flooding cycle cleans out that dam and all the barren bank. The streams widen and increase in temperature. . . . My home waters have warmed by at least four degrees in the last twenty years. This is from a combination of beavers not being kept in check and climate change. Warmer water, resulting gill lice, and resulting competition from brown trout have stacked the deck against the natives. Humans need to limit beaver expansion near our brook trout streams. Thankfully, a new regime is in place in Wisconsin as of 2019. Science will be back on the books, and our DNR will once again be staffed with caretakers of the streams, not climate-change deniers.”
Wisconsin fisheries biologist Scott Braden weighs in as follows: “We pay [USDA’s] Wildlife Services to trap beavers and remove dams in trout streams that have been badly compromised by beavers. We’ve seen great success on the few streams we’ve targeted. We’d like to do more, but the price is so high, we can’t.”
When I asked Braden for an example, he offered Beaver Creek and Buckhorn Springs. “They were really beaten up by beavers,” he said. “There was some brook trout reproduction in the headwaters. But they couldn’t get downstream; they were basically gone. All that was left were dark, sedimented backwater sloughs full of lily pads. It was just terrible. We were walking through chest-deep muck. It really gave you an idea of how much damage overpopulated beavers do. After Wildlife Services trapped beavers and removed dams, that cold water started rushing downstream and scoured out all that muck and debris, making lots of habitat. Within two years, there were just thousands of brook trout throughout the system.”
Bob Willging, Wildlife Services’ district supervisor for northern Wisconsin, reports that in 2018, his agency breached 565 Wisconsin beaver dams by hand and blew up 109 others. “The program really takes a very small percentage of beaver in the state,” he explains. “Most northern Wisconsin trout streams are small, narrow, and have a low to moderate gradient, which means a beaver-dam system floods hundreds of acres of low land, basically inundating the original stream channel. Consequently, dams on these systems may have a much greater impact on flow than a dam in the West, where the gradient is much higher. Flow is aided by elevation. So this very real impact on stream flow can result in warmer water, increased siltation and turbidity, and actual water chemistry changes. . . . Beaver are given free rein on eighty-five percent of Wisconsin’s ten thousand miles of designated trout streams, plus all of Wisconsin’s lakes, ponds, and warmwater streams.”
Photo by Wisconsin DNR
In northern Minnesota, wolves have fully recovered, but beavers have gotten far ahead of them; and with the unnatural abundance of forage, it appears they’ll stay that way. Recreational beaver trapping used to help a little, but it essentially ceased 10 years ago when pelt prices tanked.
“Forest management here is geared toward aspen, and the rotation is about forty years,” reports Minnesota fisheries biologist Jeff Tillma. “That means there’s lots of young aspen on the landscape, and that creates prime beaver habitat. Also there’s a lack of shade and large woody input in the streams. Wood isn’t allowed to get old. The trees beavers cut down are so small, they don’t stay put. We’d like better coordination between forestry and fisheries for longer-lived, uneven-aged management. Our beaver management is small scale because of the expense. We do only a handful of streams in each area, and we do them annually. If we stop for any length of time, beavers return. We’ve seen very encouraging results—more and larger brook trout.”
IN WISCONSIN AND MINNESOTA, as in Massachusetts, concerned citizens have proved they can make a difference. They’ve also proved that this isn’t always a good thing. Citing accurate but irrelevant data from the far West, they savage Midwest beaver controllers, especially Wildlife Services, which, because of its predator control, they perceive as a terrestrial extension of the underworld.
Then, too, non-anglers rarely see fish. Fish are silent, cold, slimy. So for most of the public—including a large element of the environmental community—fish don’t count as wildlife. This is why critics of beaver control invariably proclaim that restoring brook trout, a species endangered in fact if not by official decree, is solely about increasing fishing opportunity.
Herewith, a sampling of comments on sundry websites: “I personally am of the Let Nature Take Its Course school of thought and think many trout fishers here are a bunch of whiners”; “They kill and shitcan thousands of beaver and persistently drain wetlands to make it easier for duffers to fill their creels”; “The thought of how much damage is done culling beaver in the name of fishermen pisses me off”; “When humans get their hands on the naturally evolving environment, they always screw it up even more”; “Wisconsin’s beaver dam policy reminds me of a Naval Sea Systems Command policy from the 1990s: ‘Pull up the tree to see how the roots are growing.’”
Watershed Guardians, Inc., submits this advice: “One prudent course is to contact Wisconsin’s U.S. Senators and Representatives and request they defund Wildlife Services.”
[…] Thinking Like a Trout Stream […]