Dear Editor,
By some miracle, we have an animal called a beaver that builds, maintains and improves rich wetlands. However, damming behavior also creates challenging and sometimes expensive beaver-human conflicts.
Partly because of their rarity, which has been increased greatly by development, wetlands like those that beavers create have enormous value. They are critical habitat for thousands of species, including numerous game animals. They have hydrological functions such as water purification, sequestration of fine sediments and pollutants, groundwater recharge, and water storage (flood abatement). Beautiful and teeming with life, they also represent aesthetic or spiritual wealth.
As an example of the importance of wetlands, the federal government sometimes pays hundreds of thousands of dollars per acre for manmade versions that are much less valuable and natural than those created by beavers.
Beavers are mostly restricted to a tiny section of the landscape: low-gradient areas on small streams. In this beaver-damming habitat, they are able to create larger wetlands where their dams can survive high-water events.
This is where most of the beaver-human conflicts occur, particularly when high-value properties like roads abut or intersect these zones. Tiny, easy-to-clog holes in large manmade dams (roads), culverts are the biggest problem of all. They are beaver magnets.
Beavers are territorial. They typically do not tolerate the presence of unrelated beavers. Therefore, the number of beavers present in a territory, or at a given conflict point, might range from one to 10 with an average, perhaps, of three or four. Because of deaths from starvation, disease and predation (e.g., humans, motor vehicles, coyotes and bears), births and dispersal, this number is constantly changing.
When dispersing, they search for beaver-free zones, like conflict points where a kill-defense has been employed (double magnet). At a given point, therefore, overpopulation is never the problem, but underpopulation can be.
A little population management of adult beavers cannot eliminate a conflict. It takes only one non-kit beaver one night to clog a culvert. However, when all the adults are eliminated, any kits present will starve. Consequently, a little killing often leads to a lot of slow, wasteful and unconscionable dying.
To effectively protect a culvert by lethal means requires permanent extirpation. Just as the presence of beavers frequently leads to ecological miracles, their forced absence often has the opposite effect: Sterilization.
A kill-defense at a given conflict point guarantees that the problem will persist in expensive, never-ending cycles. In addition, “killing” ensures that none of the wetland values that beavers symbolize will ever persist (dams decay in their absence) or develop in the general area of any conflict point.
On a broader scale, given the inordinate value of beavers, no responsible governing agency would ever allow the overall beaver population to become low. With concern for protecting the environment growing among the general populace, it may not be politically possible, either. Therefore, we can never rely on killing, either locally or regionally, to solve the conflict.
Fortunately, there is a remedy: High-quality flow devices. These essentially control damming behavior by sneaking water away from beavers.
They are complicated engineering feats, and normally can be built successfully only by skilled specialists. When this is not the case, and flow devices have little design or structural integrity, they invariably fail. This often leads to a loss of confidence by the public in the general concept and to a doubling-down on killing.
At many places in New England and elsewhere over the last 25 years, high-quality flow devices have repeatedly proven themselves. They have saved society millions of dollars while indirectly creating thousands of acres of wetlands. High-quality flow devices can solve the problem at almost any site, generally need little maintenance, last for decades, rarely require killing, and pay for themselves many times over again. They are great investments.
Because of the limited geographical nature of the conflict, in a few weeks one competent builder with hand tools can eliminate the problem in any given town for decades. It’s thus easy to imagine beaver-proofing a small state like Vermont.
The implementation of high-quality flow devices — mostly by contractors, and largely at the Penobscot Indian Nation in Maine and several New England states — has led the world. The two leading flow device companies are Beaver Deceivers LLC (mine, from Vermont) and Beaver Solutions LLC (Massachusetts). Both companies also offer presentations and workshops, as does a nonprofit, the Beaver Institute (Massachusetts).
Their willingness to share their knowledge represents an opportunity for government managers and budding entrepreneurs, among others.
Because of a past absence of high-quality flow devices and their builders, killing has long been a necessity to protect the infrastructure. Even today, it’s sometimes an important short-term solution. Along with predators, we should thank shooters, trappers and state wildlife managers for helping with this prior defense.
But beavers can’t be an eternal enemy. It is long overdue for society to begin to make a serious transition toward a more reliable, long-lasting, economical and ecologically friendly approach.
The beaver-human conflicts present a rare opportunity for humanity to simultaneously save much money while producing scads of natural wealth. We just need to think creatively, invest wisely, and fulfill our great potential as responsible environmental stewards.
Skip Lisle,
Grafton, is a wildlife biologist and president of Beaver Deceivers LLC.
