Opinions on the Canadian beaver are as two-sided as the nickel that bears its likeness.
Beavers are often considered pests, but producers could benefit by tolerating them on their property.
Glynnis Hood, an assistant professor in the environmental sciences department at the University of Alberta, has researched possible benefits since 2001.
She said the research mainly focused on Alberta’s Elk Island National Park, near Edmonton, as well as some studies in the surrounding area.
Beavers were introduced into the park in 1952, and the population hit its peak in the mid 90s. Hood used 12 sets of aerial photos taken between 1948 and 2002, and ground data on beavers in the area.
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“It’s a study that’s relatively unique in the fact that we had such good long-term data to work with, and current data as well,” she said.
She compared water levels of various ponds and wetlands in the middle of the century to later years when beavers were present in the area.
“I was able to calculate out the area of open water in all of those years between 1948 and 2002 … and was able to determine that the ponds that had active beaver lodges actually had a significantly higher amount of water in them, even in drought, than other ponds in the area.”
Many ponds without beavers dried up during the area’s 2002 drought, while ponds with beavers maintained water levels.
Hood said she has proven the beaver population was the main factor in sustained water levels.
“We looked at a series of 70 ponds, and initially none of those ponds had beaver in them, and then in 1996 and 2002, (we) looked at those same ponds. Half of them had active beaver lodges in them, and the other half didn’t.”
Hood determined that because the climatic conditions were the same for all ponds, those with beavers have about nine times more open water than those without.
“When they weren’t in those ponds, even if they had abandoned those ponds, the water levels started going down,” she said.
In addition to the scientific analysis, Hood also provided first-hand observations.
“During the drought … people were looking for areas to water their livestock because a lot of ponds were drying up, and they started seeking out, at least in the Beaver Hills area where I was studying, they started seeking out areas that actually had active beaver colonies in them, because those were the only areas that had water in them during the drought.
Darwin Ullery, agricultural fieldman for the County of Minburn, Alta., agreed that beavers can raise water levels, but he noted that some people are unhappy with the effects beavers can have on farmland.
“It just depends where you fall as a landowner,” he said.
The benefits landowners receive from beavers will predominantly depend on what is expected of the land.
“If a landowner requires livestock water or something like that, having a dam that is strategically located will hold water back on his property,” said Ullery. “But by the same token, if it’s a grain farmer and (the dam) is flooding six acres of productive land, it’s counteractive.”
Hood acknowledges that not everyone wants dams on their land.
“Farmers are a fairly diverse group too. I come from a family of farmers and various uncles can argue things completely opposite,” she said with a laugh.
According to Ullery, a string of beaver dams built along a series of culverts can put thousands of acres of farmland underwater during times of excessive rainfall and snowmelt.
“We do very little beaver control unless they’re causing serious problems, but we do (have) to keep water moving and prevent flood damage.”
In cases where beavers are causing floods, the dams must be removed, sometimes with explosives.
“We’ve had instances where a landowner down the road wants upstream dams blown so he can get more water, but the landowner where the dams are on won’t allow us to take them out, because he wants the water. Then you get a Hatfield-McCoy situation between two landowners,” said Ullery, referring to the infamous feuding families of the American south.
