TW Viewpoint | Consider the Beaver

November 29, 2017 | Stuart Wachowicz

"In most places, a world without beavers, is a world without water and the life it supports."

What makes this astonishing creature so vital to the environment?


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For over 100 years almost every Canadian nickel (5 cent piece) has carried the image of a 60 pound rodent -"Castor canadensis" - the beaver. It remains a symbol of hard work, tenacity and duty.

The beaver is second only to man in its ability to permanently alter the environment to meet its needs. It modifies landscapes and brings water back to previously dry areas. Much research is now being done in putting the beaver to work, perhaps impacting the planet's water supply.

These hydro-engineers start in a small stream with vertically-placed sticks, then weave branches through the sticks and pack them with mud or other debris. Larger logs are positioned parallel to the water flow and bound with more mud and debris, followed by expansion in width and height. As their work causes water to deepen they widen the dam, often arcing the dam to absorb increased water pressure. They work incessantly. In northern Alberta a beaver dam over one half mile in length has been found. It has created a lake that can be seen from space. Several generations of beavers have worked on this project for over 40 years. ("World's largest beaver dam 40 years in the making"- The Star, May 7, 2010)

Beavers are designed for their role: teeth that never stop growing and cannot be worn out, bodies perfectly designed for swimming, eyes with built-in swimming goggles and the ability to stay submerged for 15 minutes. They are built to lift many times their own weight, pulling heavy logs to the water. They could not have been better engineered for their role.

They are motivated by the sound of running water, indicating a threat to their lodge, as the lodge must be in deep enough water to permit an entry below the ice in winter. Thus flowing water must be stopped. In one case a recorder, playing the sound of running water was left in an area populated by beavers. In a matter of hours the recorder was "dammed", buried in mud.

An adult beaver can cut down over 400 trees per year for dam and lodge-making operations, and for food, as tree bark is their primary diet. Some say this is destructive, yet cutting down sections of the forest around a pond results in opening the area for lush new growth of grasses, young trees and shrubs, increasing the food supply for wildlife, with an abundant supply of water in the pond. Thus the ecosystem is renewed and sustained by the beaver. When the pond eventually fills with silt and plant debris, they move on, having created a new meadow. The old dams, hidden from sight, cause water to be trapped under the new ground surface, protecting the area from future drought.

Dr. Glynnis Hood has spent years studying and documenting the activities of beavers and their impact on landscape. Alberta's Elk Island National Park is a perfect laboratory, providing 54 years of records on beaver populations and open water in times of rain surplus and drought. Her book, The Beaver Manifesto records that long-standing ponds and lakes with beavers had a staggering nine times more open water than ponds where beavers were not present, regardless of rainfall amounts. She shows the impact of the beaver in drought-proofing the ecosystem. In 2002 Alberta had one of the worst droughts in its history. In Elk Island Park the only places with much ponded water had beaver populations.

Still some find the beaver a problem. The traditional practice has been to dynamite dams or kill them. Neither have been successful strategies. Such was the experience of Michel Leclair, manager of Gatineau Park in Quebec. As shown in the CBC documentary, the Beaver Whisperer. He tried dynamite and traps for many years, with very little success. They still blocked culverts and flooded roads. Today however, Gatineau has one of the world's highest populations of beaver, yet most of the problems have disappeared. The beavers now work for Leclair.

Since the sound of moving water motivates them to build dams, he created the sound of running water by the use of posts in streams, directing the beavers to locations where Leclair wanted the dam to be. Today he runs an efficient water management system in a huge park with hundreds of beavers serving as his willing, non-union, unpaid civil servants. To construct dams, even small ones, require design, engineering reports, environmental assessments and construction contracts. It is expensive and time consuming. The beavers do the job for free in a matter of days, once he directs them to the work site.

The beaver, an environmental super hero whose work stores water for all manner of life, protects the ecosystem from drought, filters water pollutants, opens forests for new growth, turns desolate areas and small streams into fertile meadows, and restores ground water, deserves some appreciation. The beaver is not an accident of nature, but a vital piece of a grand design.

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I'm Stuart Wachowicz for Tomorrow's World Viewpoint.

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