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Whistler – Valley of the Dammed

Whistler Biodiversity Project

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Most people associate beavers with the Canadian nickel, fashionably gaudy hats, or dams that cause countless problems for people, farms, and businesses. From an ecological perspective, however, beavers are a crucial component of wetland areas like Whistler Valley, and that’s why the Whistler Biodiversity Project has started a two-year project to study beavers.

Beavers ( Castor canadensis ) are second only to humans in their ability to alter the landscape, and for once, this is a good thing! Beaver dams create suitable wetland habitat for many species of mammal, waterfowl, reptile, fish, amphibian, insect and/or the latter two’s eggs and larvae. Dams also reduce erosion, absorb the deposition of eroded sediments during floods, raise groundwater levels, and initiate the process of forest succession. Before Whistler developed, beaver activity would have shaped the landscape.

The retention of beaver ponds in the Whistler area is of great importance ecologically as these bodies of water may be critical habitat sites for threatened species like the Western Toad, Red-legged Frog (only recently discovered in Whistler) and birds that use ponds located on migratory flyways. Beaver ponds in the Whistler valley may also be home to other rare species such as Fishers, Townsend’s Big-eared Bats, Great Blue Herons and Green Herons. This makes our little lumberjack a keystone species.

Many people have seen signs of beaver activity but have never seen the beavers responsible for taking down the tree in their front lawn. That’s because these amazing animals are primarily nocturnal, foraging in the twilight to avoid predators. Their family unit, or colony, consists of a male and female, yearlings, and the current season’s kits. This makes for a full-lodge!

After their second spring with their parents, the two-year-old juveniles disperse to ease pressure on the food supply and avoid the risk of inbreeding. This is about the time they move into a new area, find a suitable stream, and dam it. Because beavers are incredibly awkward on land, they dam streams to create a water-surrounded world to protect themselves from terrestrial predators and stay close to their food supply, a diet consisting of cottonwood, willow, and assorted riverbank plants they cache as a pile of sticks close to the lodge.

Beavers don’t just feed on branches for sustenance, their front incisor teeth never stop growing so they have to wear them down with hard cellulose, a.k.a. wood. Contrary to popular belief, beavers do not hibernate during the winter and actively access their food cache all winter long.

“Busy as a beaver” goes the old saying and that is especially true come fall when beavers are most active gathering and storing food for the winter ahead. This increased activity outside the safety of the lodge makes them vulnerable to predators. If they escape four-legged predators and their occasional lack of directionality in tree felling, they still have to contend with their most fierce and cunning predator, humans.

Humans generally consider beavers a nuisance and so destroy the beavers and their dams to allow water to continue flowing. This has led to the extirpation of the species and the decline of fish, amphibian, insect, mammal, reptile and waterfowl species in Whistler and other places. Thus, coexisting with beavers is paramount in the stability of local populations of many species and the key to achieving this is public education and awareness. There are, for instance, humane and inexpensive methods that may be employed to resolve common Beaver-human conflicts:

• Tree trunks can be made aversive or inaccessible to Beavers; important trees around golf courses and in neighborhoods can be protected from beavers by either wrapping the base in a wire mesh or spraying them with a Bobcat/Coyote musk or pepper spray.

• Use of outside motion-detectors equipped with the sound of barking dogs can also be used in areas where the felling of trees is trying to be prevented (You can substitute the sound of barking dogs with the sound of Celine Dion’s voice, both of which are aversive to the auditory canal).

• The best systems for controlling beaver flooding are based on deception and exclusion. Dams can be penetrated without compromising the structure or alerting the beaver. As many of you who have tried to disassemble a dam only to have it rebuilt the next morning know, beavers use audible stimuli in orienting construction behavior. This means a beaver will repair any part of its dam where he hears running water. To keep the dam but still allow water flow, you can use perforated PVP pipes, posts and wire mesh to probe the dam and allow water to flow. This system will not work in less than a half-metre of standing water or in areas where a large volume of water must be moved.

Conservation, preservation, management and ability to work with beavers is crucial for the stability of locally sensitive populations of species that rely on it for critical habitat. That is why we need your support in reporting past and current beaver sightings. As part of the Whistler Biodiversity project, a multi-year, multi-group effort to catalogue and protect native species, we are doing a two-year preliminary census of beaver populations in Whistler. We hope to determine population numbers, distribution and history of all beaver activity in the Whistler Valley.

If you have seen a beaver or seen signs of beaver activity in Whistler, please report your sightings to www.whistlerbiodiversity.ca . We appreciate all input and will add new information about local beavers (and other species) to the website as it comes in.