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Beavers — nature’s landscapers — are making a comeback

Article by Lynda La Rocca

Wildlife – May 2000 – Colorado Central Magazine

ACCORDING TO THE CALENDAR, it’s springtime in Central Colorado — recent whiteouts notwithstanding. The ice on the Arkansas River near our Lake County home is just starting to break up, yet it’s still solid enough to walk on in most places.

Cautiously approaching a pool of water that has opened in the snow-dusted ice of a river tributary, my husband, Steve, and I come upon a cluster of slightly fan-shaped, webbed tracks, partially obscured by what look like drag marks.

A glance at the freshly cropped willows and alders along the bank confirms it: Castor canadensis, the North American beaver, has been here.

This creature’s extraordinary ability to modify its environment is second only to man’s. After felling trees, cutting them into manageable sections, and eating the bark, leaves, and young, tender branches, these natural recyclers combine the stripped wood with mud, and sometimes with rocks and even corn stalks, to build dams — some more than 1,000 feet long — across streams and slow-moving rivers. The downed trees also provide building material for the beaver’s large, cone-shaped living quarters or “lodge.”

To keep its amber-stained central incisors or front teeth neatly trimmed, the beaver spends much of its time gnawing on favorite trees, including willow, aspen, alder, cottonwood, poplar, and birch. This steady chopping and chewing, along with its tenacious dam-building (the latter instinctively triggered by the sound of running water), have made the beaver a symbol of perseverance and industriousness in many cultures.

North America’s largest rodent is found just about everywhere on the continent, with the exception of much of the southwestern desert and Mexico, the arctic tundra, and parts of peninsular Florida. Colorado’s beavers, while most abundant in subalpine zones, inhabit the entire state.

“You’ll see them just about anywhere there’s aquatic habitat and a year-round source of water,” says Mike Yeary, district supervisor with the U.S. Department of Agriculture’s Wildlife Services.

Humans have long had a love-hate relationship with these critters, which can reach lengths of 30 inches — not including their scaly, paddle-shaped, 10-inch-long tails — and weigh up to 60 pounds. (Ninety-pounders, or beavers “of density,” to borrow a phrase from humorist Dave Barry, have also been reported. And even they are lightweights compared to extinct varieties from the Pleistocene Epoch, which grew to nine feet and tipped the scales at 900 pounds.)

While Native Americans viewed the beaver as the land’s “sacred center” because of its ability to create rich habitat for fish and other mammals, European newcomers looked at the animal’s soft, thick, brown fur and saw dollar signs.

Fashion plates of the 18th and early 19th centuries wouldn’t think of being seen in public without the requisite beaver-fur hat. But by 1834 silk had usurped beaver fur — and not a moment too soon for a species which had already been nearly extirpated by rampant trapping. Beaver trappers had also, for better or worse, blazed the trail for Anglo settlement of the American West — but that’s another article.

Although today’s beaver population has rebounded, but only to only a fraction of its original numbers, the beaver is not currently considered a threatened or endangered species.

Colorado’s Division of Wildlife classifies beavers as “furbearers . . . that may be trapped for their fur.” (A market for it still exists in the U.S. and overseas.) The animals are hunted statewide on both public and private land during a season that generally runs from October through April. Beavers damaging agricultural property may also be trapped during one 30-day period per property per year using “conibear,” or quick-kill traps.

Monetarily speaking, the beaver’s penchant for building dams in culverts is its worst characteristic. Nationwide, millions of dollars are spent each year to repair resultant roadway flooding.

But relocating or destroying the offenders is no solution, because habitat that looks good to one beaver will prove equally suitable to successors, says the New York-based advocacy group “Beavers: Wetlands & Wildlife.”

“Because of the species’ benefits in creating vital wetlands, and because removal is rarely a lasting solution, working with beaver gives the best results,” the group’s Web site explains.

FOR INSTANCE, road flooding can be prevented by installing wire mesh around culverts. A method popular in New England involves “exclosures,” special drain pipes added to welded fencing to control water levels, yet permit free water flow even if a dam is constructed. Trees can be protected with trunk cages of heavy wire mesh, the height depending on local snow accumulation. (Beavers can stand atop winter snow to reach several feet up a trunk.) Low-strung, electrified-wire fences or small-mesh fences with smooth metal posts that prevent beavers from getting a climbing foothold also promote human-beaver harmony.

For the past several years, we’ve spotted individual beavers easily weighing 40 pounds or more busily harvesting succulent shoots or negotiating the currents of the Arkansas River. Since we have yet to discover anything even remotely resembling a lodge, we assume that these beavers are either digging burrows with underground entrances along the banks or simply passing through the watershed.

Because beavers are considered a “keystone species” in riparian communities, namely, a species whose disappearance would profoundly impact the ecosystem, it’s especially heartening to see them along the Arkansas. Longtime residents will recall that, through the 1980s, water as orange as the beaver’s front teeth frequently inundated this river, the result of upstream mine drainage pollution.

So despite ongoing grousing over the continuing presence of the federal Environmental Protection Agency, I say, thank you EPA. From where I sit, the law of unintended consequences is fulfilling its purpose — because the beaver are back!

Lynda La Rocca lives and writes between the Arkansas River and the summit of Mt. Elbert, when she’s not teaching at Colorado Mountain College.