Learning to Love Beavers' Wetland Work
More than 350 years after a taste for fur hats nearly wiped out North America’s beaver population, landowners and ecologists have a new appetite for Castor canadensis. But this time, luckily for the beaver, we only want them for their work.
With their natural engineering skills for dam-building and water storage, beavers do an amazing job of creating diverse habitat. In fact, they’re so central to ecology that they’re known as a keystone species, one without whom whole ecosystems would – and have – failed. They’ve been shown to mitigate both flood and drought, raise water tables, regulate the flow of water and sediment in rivers and streams and help native fish populations. New research shows that their engineering work may also reduce damage from wildfires.
Beavers are the original watershed stewards. Photo: Miistakis Institute
So why, with all the benefits they provide, are beavers often still treated as pests on the landscape? Part of the reason, suggests Dr. Cherie Westbrook, a professor and the director of NSERC CREATE for Water Security at the University of Saskatchewan, is that people are not used to coexisting with beavers. When colonists began settling and farming in southern Alberta in the late 1800s and early 1900s, beavers had already been extirpated from the local landscape. As their populations began to rebound, their efforts at creating wetlands were not always appreciated. “If people have seen something as a nuisance,” Westbrook said, “it’s very hard to see them as a [useful] part of the ecosystem.” Helping people understand that beavers were here long before settlers – and that they can restore and create wetlands – is just good education, she added.
Two groups working on educating Albertans about the benefits of beavers are Cows and Fish and the Miistakis Institute. Since 2012, they have been collaborating on a project called Putting Beavers to Work for Watershed Resiliency and Restoration. The project began with a plan to reintroduce beavers to the Ann and Sandy Cross Conservation Area (ASCCA) southwest of Calgary and to monitor the impact of those beavers on the area’s conservation efforts.
The ASCCA now boasts a small beaver population (which began with several rehabilitated orphans), and Putting Beavers to Work has meanwhile gathered research and translated it into management tools that help humans and beavers coexist. Word of the initial project has spread widely, starting with landowners close to the Cross Conservation Area. Holly Kinas, a conservation analyst with Miistakis, has received requests for information from as far away as Mongolia and Germany, although most of the project’s outreach work is in Alberta and British Columbia.
Beavers have dammed Bragg Creek west of the parking lot at the West Bragg Creek Day Use Area. Photo: Ann Sullivan
Kinas said there has been a shift in recent years in Albertans’ perception of and tolerance for beavers on their land. “The majority of people do like them and see their value,” she said, although they might not appreciate the felling of mature trees and the flooding of their pastureland and roads. “If we can mitigate some of these headaches and make the case for keeping beavers on the land, we’re all better for it,” Kinas said.
Norine Ambrose, executive director of Cows and Fish, agreed. “People’s first gut reaction to [beavers] is changing,” she said, adding that it’s now more common for people to ask how they can manage beavers, rather than how they can get rid of them. While there’s still lots of room for education and awareness, Ambrose has noticed that an increasing number of landowners and municipalities are opting to use management tools as a means of coexistence. “People didn’t even consider those options years ago,” she said. “That’s a pretty powerful change.”
Some of the management tools developed and promoted by the Putting Beavers to Work project range from wire wrapping or chemical repellents on trees to pond levellers and culvert protectors. Cows and Fish uses a “train the trainer” approach to teach municipalities and landowners how to install and maintain the tools.
A pond leveller, for example, can regulate the outflow of a beaver dam to keep ponds at a desired height and prevent flooding in unwanted areas. Culvert protectors, installed on the upstream side of a culvert, prevent beavers from flooding roadways. These tools relocate the sound and feel of running water – both of which instinctively trigger beavers to start making repairs.
Find more information on beaver coexistence tools at communityconserve.ca/beavers.
Both tools are more cost effective (between 62 and 90 percent) than traditional means of managing beavers (dam removal, trapping, animal relocation, etc.). Older methods have proved to be ineffective, short-term and costly. “Relocation is not an easy feat biologically,” Kinas said, “and also from a regulatory perspective, it’s not an easy tool.” Tools like pond levellers and culvert protectors pay for themselves in the long run, she added.
Cost benefits are not the only reason that Albertans are embracing coexistence with beavers. A 2017 survey by Miistakis and Cows and Fish showed that more than half of respondents were in favour of beavers on their land, despite the challenges their dam-building may cause. As one respondent noted: “I like the benefits that come with [beavers], and just like everything in life nothing is all good but the concerns I get over time are limited.” Other landowners noted that in dry years, beavers have provided a valuable source of water – sometimes the only source of water – for their livestock.
In the Elbow River watershed and most of southern Alberta, drought is a challenge that a healthy beaver population can mitigate. In a webinar called Beavers in Healthy Watersheds, Cows and Fish’s Ambrose noted that areas with beaver evidence before a drought continue to have much more water during a drought than watersheds without beavers. That is true even if the beavers themselves have left and only their structures remain. A beaver dam can increase water flow downstream by 2 to 10 percent. “It isn’t of course that they magically create new water,” Ambrose notes in the presentation, “but it’s because they’ve held onto it and trapped it and stored it that it can persist and increase that flow that wouldn’t otherwise have been there...”
Scientists estimate that the beaver population in North America once numbered up to 100 million, or between 5 and 30 beavers per kilometre of rivers and streams. The large rodents may be making something of a comeback in Alberta, but scientists don’t know for sure. Kinas said that’s something Miistakis would like to study.
There’s a misconception, Kinas said, that beavers are abundant because most people have seen a beaver pond or dam. But because beavers are often treated as pests, evidence of their habitat is not necessarily evidence of their colonization. Development and increased human population mean that beaver habitat is shrinking and river connectivity is harder to find. Still, beavers’ ability to create and improve habitat – and our willingness to live with them – helps improve their chances of thriving in Alberta and elsewhere.
“I think they’re amazing creatures,” said Kinas, adding that it’s not necessarily the love of beavers that drives the desire to protect them and promote coexistence. “It’s so that we can see those benefits on the landscape.”
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