Beavers are dam important for the ecosystem

​The beaver is a Canadian icon. To some it's also a royal pest.  

Beavers are more than just a nuisance, though. They are also important engineers of our environment.  

A new study published in the journal PLOS One has discovered just how important beavers are in protecting habitat.  

Why are beavers considered pests by some?

I know some people are annoyed with beavers because they chop down trees, flood areas with dams and can generally not be on the same page as a landowner about how to engineer the land. But they are gaining more and more acceptance as important natural engineers of their environment.

Beavers, of course, are compelled to build dams, and research has revealed that beavers build dams near the sound of rushing water.

Of course, they build dams to provide habitat and protection for their young. And, as a consequence, they can stop a rushing river in its tracks and force water to slow to a crawl creating a beaver pond.

What role do beaver ponds play in the ecosystem?

There are lots of species that rely on beavers to engineer the environment to suit their own needs. Creatures like the Sandhill crane, the mule deer, and, most importantly, juvenile fish. Not only that, when there is a beaver pond, the water is able to be better absorbed by the land, allowing it to resist both droughts and floods a lot better. 

For a long time, it was believed that beaver ponds increased the temperature of water in the ecosystem due to its greater surface area absorbing more energy from the sun. That was always thought as a possible way that beaver ponds could be damaging the surrounding ecosystem.

This assumption has been overturned by new research.

Nick Weber is with Eco-Logical and his team conducted experiments along Bridge Creek, Oregon.

"As the volume of surface water increases," he says, "it just takes a lot longer for streams to heat up during hot summer days."

The work was done in the high desert of Oregon where temperatures can soar in the summer. But it's not much different from what we can get in Canada, especially as our world warms.

Why is this significant?

It's significant because the high temperatures of river water — which on some days can reach up to 29 C — is problematic for fish like salmon and trout. These fish need temperatures closer to 25 C, which is exactly what is achieved by having a beaver pond. Having much cooler water increases the survival of juvenile fish like the steelhead trout. 

Needless to say, when we are living in the current warming world, it's important to find ways to reduce the impact of higher global and water temperatures on important stocks like salmon.

What kind of role could beavers have in the future in preserving habitat for these fish?

That's the interesting thing this research found. The group constructed what they called beaver dam analogs In other words, they tried to make their own dams in areas that were in need of restoration. 

Weber was the team lead on beaver dam construction, and they followed the beavers' lead. They started by, "just pounding posts into the stream.

"And then we just learned from beavers. We copied their approach by taking existing riparian vegetation — willow and alder — and just weaving them between the posts to construct a beaver dam analog."

The method proved both successful and cost efficient.

So the proposal is to take inspiration from nature, and the beaver, to help restore habitat by constructing artificial beaver dams.  And the coolest part is that beavers eventually take over the dams after a few years.

Not only can the dams restore river systems, but it means beavers might be guided into building dams where they might reduce the impact on people's lands.