Beavers have been given a bad rap, but they can benefit the landscape — and there are ways of coexisting with them.
“People are beginning to recognize the value of beaver and how they might be able to help us as a society navigate some of the challenges we are facing,” riparian specialist Kerri O’Shaughnessy said during a recent virtual talk hosted by the Pigeon Lake Watershed Association.
Her organization, Cows and Fish, has been working with the Miistakis Institute and provincial officials to help landowners who aren’t so enamoured of Canada’s most famous rodent (which, since 1975, has been the country’s official emblem).
In addition to toppling trees, beavers can cause “unwanted flooding” as well as damage to infrastructure, the Miistakis Institute — which is dedicated to finding solutions to environmental problems — concedes in a new booklet on “beaver coexistence tools.”
“Beavers have been recognized as important for climate resiliency as they facilitate groundwater storage, increase stream permanence, enhance water quality, mitigate floods, create terrestrial and aquatic habitat, among myriad benefits,” the booklet states.
Both the good and the bad begin with running water, which triggers beavers to build dams, said O’Shaughnessy
“The lodge is the castle for the beaver,” she said. “It’s where they get out of the elements, get away from predators, store and cache food. The pond around that lodge is the moat of the castle.”
Dams vary in size and shape — and often there’s more than one.
“There’s a lot of pressure in them, but leaks and areas where the water can escape allow dams to stay in place for a very long time,” she said.
“(And) having a series of ponds basically builds up that network of where they can be safe.”
Beaver ponds also act as filters for run-off, including agricultural run-off.
“Plants and organisms in that beaver pond can use and break down that sediment and things attached to them,” she said.
“Beaver ponds, particularly in dry years like this, have some of the only surface water that we can see. It also influences what we can’t see, underground.”
Ponds not only retain more water on the landscape but can offer protection against wildfires and slow flood water in a watershed, she said.
But beavers themselves don’t give a hoot about property lines or what they’re flooding — which can be roads, fields, and fences. In fact, a culvert with flowing water looks like a good place to homestead to beavers (which are very territorial and so young beavers must stake out their own ground).
“Municipalities have a real challenge in managing beavers,” said O’Shaughnessy. “They can affect animal safety as well as human safety.”
And sometimes living up to their reputation for being busy leads them to chew on things such as phone cable or PVC pipe.
Traditionally, the solution to problem beavers was to trap or hunt them (moving them to another place is illegal in Alberta). But when a beaver or its lodge are destroyed, the problem is rarely solved for long, as another beaver will show up within a few years.
But there are alternatives that are cost effective and can maintain the land around the pond for economic, environmental, and other benefits, said O’Shaughnessy.
One is something called a pond leveller.
It’s a pipe that has an inlet in the pond (surrounded by a cage) and extends through the beaver’s dam. The idea is to keep the pond deep enough so the entrances are submerged while providing an outlet so the water level in the pond can’t get too high to flood property or damage infrastructure.
The biggest problem with pond levellers is red tape, the Miistakis Institute says in its booklet. Sometimes no permit is required but other times “rigorous and expensive requirements” are mandated by Alberta Environment and Parks, says the booklet from the institute (which has been conducting workshops on how to build pond levellers).
There are also culvert protectors, which are simple structures to prevent a beaver from damming a culvert (again a permit may, or may not, be required). Wrapping wire around trees prevents beavers from chewing on them (the wire should be loose to allow for tree growth and be a metre high) and exclusion fences can also keep beavers out of certain areas.
Some landowners have also got creative, leaving piles of aspen and willow (beavers’ preferred menu items) as woody buffets, said O’Shaughnessy.
Using an old ghetto blaster to play the sound of running water can also entice the beaver to build in another location.
Many of the solutions to allow the beaver to coexist on the landscape are more cost effective in the long run, and allow the landowners to enjoy benefits, she said.
The Miistaskis Institute booklet can be found at rockies.ca (there’s a link on the home page or in the Resource Library) and can be downloaded for free.