Beavers – Nuisances or Watershed Heroes?

October 11, 2017

For CFC’s inaugural Beaver Month we chatted with Andrew Jakes, Regional Wildlife Biologist for National Wildlife Federation about the unsung bucktooth heroes of the watershed – the beaver.

Why are beavers considered ecosystem engineers?

Beavers aren’t just considered ecosystem engineers…beavers are THE quintessential ecosystem engineer! They change a landscape like no other species in the world, besides humans. They change the landscape to suit their needs, and when they do that, it turns out that they change a lot of other things too.

Why do beavers build dams in the first place?

Beavers ultimately build dams as a defense mechanism. Some beavers live in river banks, but most beavers live in a lodge, which requires a pond. They build the dam, so that they can build a lodge, so that they can raise a family and stay safe from predators. Another reason they build dams is so they can create their own food source; beavers are vegetarians and they love eating aquatic vegetation. Emergent vegetation (plants that grow in wetlands and along the shore) is like their ice cream. Beavers in Montana also love willows, cottonwoods, and other riparian vegetation. They create ponds so that the food they like to eat will grow. 

OK, so what else changes in the landscape when beavers are present and building dams?

beaver damSo much! When beavers show up, a lot starts to change. Studies have shown that beaver dams change everything in the system; from soil to vegetation to water quality to wildlife. It’s hard to sum up in only a few sentences, but I’ll do my best to give you a summary…

First of all, beaver dams slow the flow of water. This means water is on the landscape for longer. This can cause the floodplain to expand, soil structure to change, and the water table to rise. All of this also means that riparian vegetation can thrive. This means extra foraging opportunities for beavers and other creatures, so more wildlife starts to frequent the area. It’s no secret that wetlands are beneficial to the ecosystem, and beavers are little wetland creators.

The bottom line of all this is that when a beaver dam shows up, we see an increase in biodiversity, which thereby means the ecosystem becomes more resilient.

It sounds like beavers are pretty nifty from a conservation standpoint

Yeah. When beavers are re-introduced back into the environment, we see a see a bump in biodiversity in that area. It’s pretty incredible, and it means that the environment is more resilient to disturbance—whether that disturbance is human caused or natural, the area will likely bounce back faster than it would have pre-beaver dam.

Want to learn more about beavers and conservation? Join the Clark Fork Coalition and National Wildlife Federation at Imagine Nation Brewery on October, 25th at 5:15pm for a presentation about Busting Beaver Myths.

Many Montanans see beavers as a nuisance. Why is that?

Well, as we already talked about, beavers change a lot of things in the ecosystem. From one viewpoint, this is incredible, but when beavers start engineering your property to suit their own needs, it can be a real pain. Beavers can take over valuable land with their ponds and are infamous for flooding roads. Because beavers are looking for water that is flowing and a stream width that is easy to dam up, culverts are often a target for beavers. Obviously, this leads to flooding issues, as blocking up a culvert means a quickly flooding roadway. Beavers are also extremely territorial, so getting rid of them or moving them to another location is very challenging.

There’s also the issue of folks downstream from a beaver dam. When a stream gets dammed up, the flow of water can turn into just a trickle. That means, if people downstream are depending on that water (i.e., for their crops), they’ll likely see less of it at one time. However, even though a beaver dam upstream might mean you will get less water at one time, it also means there will be a dependable flow all year. So, it really depends on the lens you’re looking through, if you see beavers’ actions as a curse or a blessing.

So are there ways landowners can mimic beavers without the problems that they ultimately create?  

Since beavers can be so beneficial to a landscape, there are plenty of landowners who love having them around. One solution is to fence culverts, so beavers can’t get close enough to dam them up. Check out beaver deceivers to learn more about more ways of preventing beaver damage to culverts.

Another tool in the toolbox is the beaver dam analog (BDA). BDAs mimic beaver dams in the wild, but are created by humans. By building these human-designed natural dams, landowners can target areas that might need the benefits of a beaver dam, in a more controlled manner. Depending on the scope of the project, BDAs can be used to introduce beavers to an area, or simply mimic beavers’ actions without beavers being present. Learn more about beaver analog dams here.

Anything else you’d like to add?

Beavers are way more badass than you would ever anticipate! Even though they’re cute, they can be aggressive, and aren’t afraid to defend themselves or their home.



< Back to blog