Mark Trail’s Beaver Tales

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As any avid consumer of the Star Tribune‘s comics page knows, a certain pesky, but lovable, woodland creature called “Lucky the Beaver” is driving Mark Trail to distraction these days. Since early December, Lucky has been raising a ruckus in Lost Forest by doing what Castor canadensis does best: building a dam. All that damming is coming at the expense of some trees owned by a neighbor of Mark’s. The famous outdoor writer has been called in to take care of the problem, without harming Lucky and his mate, of course. With the exception of Larry Flynt, perhaps no creative machine has done more to anthropomorphize beavers than Jack Elrod, the current artist/writer behind Mark Trail. “Meanwhile, Lucky, once befriended by humans, can’t understand why his mate has been taken away,” goes the narration in the Jan. 5 edition of the strip. (By the way, Elrod has also done much to advance the use of loud punctuation in comic strips—adhering to the philosophy that anything worth saying should be blessed with an exclamation point. Case in point: “…they are clever little creatures!” Trail exclaims as he releases a beaver from a live trap. Is the guy he talking to hard of hearing, or is Mark just really, really impressed by how clever beaver’s are?) Mark Trail’s presentation of nature as a place where wild animals have human feelings, loud outdoor writers never have to meet deadlines and bad guys always have long, thick sideburns has been an irritant of mine for years. But the current beaver-related storyline reminded me of an interesting real life beaver tale that’s taking place in farm country these days. It’s occurring without exclamation points, but it’s an example of what can happen when human engineers get out of the way and let their rodent counterparts put in a few hours of construction time.

It’s hard to find a lazy, looping stream in agricultural areas. Most channels have been straightened and dredged to within an inch of their life in an attempt to keep water off crop ground and push the wet stuff downstream as quickly as possible. This has resulted in unstable stream banks that constantly erode. Attempts have been made over the years to stabilize stream banks with the best engineering money can buy. These mitigation attempts are expensive and often provide short-term fixes at best.

But research in Nebraska shows that nature itself may provide a more sustainable way to stabilize creeks in the form of an animal that is usually considered a pest in agricultural areas: our friend the beaver.

A beaver never saw a moving body of water that it didn’t want to dam up, as anyone who has tried to unclog a beaverized culvert can attest to. While they are usually associated with wooded areas of the country, beavers have actually made an impressive comeback in intensively farmed parts of the Midwest during the past several decades.

Researchers at the University of Nebraska-Lincoln studied a stretch of a stream in Otoe County, in the southeastern part of the state. What they found was that six dams built by beavers on Little Muddy Creek created a stair-step effect in the stream channel, significantly slowing the water’s velocity and trapping a huge amount of soil sediment. On one 730 meter-stretch of the creek, over 1,730 tons of sediment was collected behind beaver dams during a 12-year period.

The beavers did all of this basically for free (not counting all of the corn stalks they cut down over the years). In contrast, in a nearby watershed where human-engineered structures were used to stabilize almost a kilometer of a degraded stream, the price tag was $110,000.

I’m no hydrologist, but I’ve seen firsthand just how effective beavers can be at creating a little nature in the midst of an ecological desert. Southwest Iowa’s 7-Mile Creek is in the heart of corn and soybean country. At times, the erosion can be quite tremendous, and parts of the creek are constantly slabbing off, creating sharp banks and water the color of Willy Wonka’s chocolate river. Vegetation has little opportunity to hang on, leaving the area along the creek bare, slick with mud and pretty lifeless. But one stretch of the creek has been home to a beaver dam in one form or another since at least the late 1970s.

A month ago, I drove down a gravel road, stopped on an old iron bridge that spans the 7-Mile and looked upstream. Sure enough, that dam was still there. And sure enough, the area immediately below the dam was characterized by a gently sloping bank, lots of grass, even a few trees.

You can see for yourself in this photo I snapped:


At the top of the photo, looking like a thin, black Band-Aid, is the dam. But it’s doing more than covering a wound—it’s creating a nice little semi-permanent island of healthy hydrology and wildlife habitat. It’s hard to describe just how bare and desolate the corn and soybean stubble was just beyond the creek banks. But in this little 7-Mile Shangri-la, muskrat, mink and coon sign were all over the place. Even a few ducks were using the pool created by the dam. That water wouldn’t have passed even the most minimal pollution standard, but at least it wasn’t tearing away at the sides of the streambank like a jet-powered bulldozer. For the farmers who are farming along the creek, that means less of their real estate is heading downstream. Below the bridge I was parked on, the county engineers had planted iron, rock and timbers in an attempt to replicate what the beavers had accomplished a hundred yards upstream. The county’s work had left a stream bank that was somewheat stable, but it didn’t have the permanence (or natural beauty) of the beaver habitat.

The beaver’s engineering talents are starting to be appreciated by land managers in other parts of the country, as the essay “Wild Work Crew” describes in a new book, Farming and the Fate of Wild Nature.

I’m not going to pull a Mark Trail and romanticize beavers. Their penchant for dam-building can do major damage in rural areas. They can destroy valuable trees, flood fields and transform roads into rivers. A pair of beavers can cut an impressive swath through a cornfield. But as Jason Abraham’s excellent article in the January-February 2007 issue of the Minnesota Conservation Volunteer points out, there are effective ways of controlling the bucktooth. We don’t need to coddle the beaver in unrealistic Mark Trail fashion; but neither do we need to condemn them bad-guy-with-sideburns style either.

That’s the kind of balance we have to strike when trying to produce food on the land in a sustainable way. We’re seeing an increasing number of farmers starting to look at natural “pests” in a new light, resulting in production systems that are profitable and good for the environment. This requires getting off the tractor and doing some pretty intense observation of the land, the kind that Minnesota’s Monitoring Team pioneered in the 1990s. A few years ago I interviewed David Podoll, a North Dakota farmer who had developed an intricate way of controlling Canada thistle in his grain fields utilizing a rust disease and the painted lady butterfly. It was an ingenious ecological dance that required the farmer to actually leave stands of Canada thistle alone, rather than attack them vigorously with chemicals (talk about self-control) every time they popped up. I asked Podoll how the heck he ever arrived at this clever system.

His answer? “You just watch.”

The farmer’s answer makes the type of monitoring he and others do sound deceivingly passive. But as a wise person once said, there’s a difference beween “looking” and “seeing.” When I looked at that gob of sticks, corn stalks and mud that spanned the 7-Mile a month ago, I saw a little of that creek’s past, and maybe a little of its future.

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