Living with Nature’s Engineers

The western landscape is quite different than it was in the 1800’s for several reasons, however an event with arguably the most significant impact is the near elimination of the beaver. The once plentiful beaver population diminished to near extinction when the fur trade exploded and this dam creature was trapped and hunted.

Now, the beaver is making a comeback in Western Montana, causing mixed opinions among landowners and the public.

“Beavers are unique creatures,” says Connor Parrish, a Project Manager for Trout Unlimited (TU). Their damming habits can benefit both fish and wildlife species, and are crucial for promoting stream health, essentially acting as a filter when water flows through their porous structure. Beaver dams create wetland habitats by slowing and redirecting stream flow, allowing water to remain on the landscape for longer periods of time, which is critical in water-scarce regions. This also means that water is around later in the year, which may be especially advantageous for cattle ranching operations.

Furthermore, Parrish encourages people interacting with beaver dams to “embrace the mess.” The rich, riparian habitat created by beaver activities allows many different species to reap the benefits. The cooler stream and pond temperatures attract native fish populations, as well as providing a variety of diverse aquatic areas that are suitable for juvenile fish. Beavers often use quick-growing trees, such as willows and cottonwoods, to build their dams, facilitating growth for new sprouts and clearing the way for greater green cover for larger mammals.

The ecological impact that beavers provide is indisputable, but beavers often receive a bad reputation from humans. If their engineering efforts are not redirected, they could cause property damage or disrupt agricultural operations. Traditionally, this response has not been good for beavers. Many conflicts result in the trapping and killing of the nuisance beaver; however, this response is often short-lived, as the elimination of one beaver does not prevent others from finding the area a suitable home. “Beaver conflict results from an attractive habitat. If you’ve seen beavers once, you’ll likely see them again,” says Parrish. There are more efficient and sustainable measures than trapping and other lethal control methods.

A key concept in addressing human/beaver conflicts is adaptive management, meaning there is no ‘one size-fits-all’ solution. It is important to understand that every site is different, therefore how one chooses to mitigate beaver disruption may vary. Two of the most common problems that people face when dealing with beavers are tree damage and flooding.

To protect trees, TU’s Connor Parrish recommends wrapping beaver-threatened trees with cylinders of heavy wire that beavers cannot chew through, such as cattle panel. This infrastructure can be applied to individual trees or can be clustered depending on the preference of the landowner and layout of their environment.  It is important when wrapping trees to provide ample space between the tree and the wire structure to allow the tree to grow and the solution to be more sustainable long-term. This protects the tree and forces the beaver to turn to other options for building supplies.

The beaver deceiver is a flow controlling device that is often implemented when beaver activities, such as clogging culverts or bridges and flooding fields, disrupt human interests. The pipe and fence-based structure keeps water levels manageable for both property owners and beavers by redirecting water from one side of the dam to the other, with a fence structure on one end to prevent beavers from clogging the pipe. The pipe would also ideally be placed underwater to prevent the beaver from hearing the flowing water that calls them to action.

Marina Smith, the ranch manager of Elk Meadows Ranch, in the Madison Valley, recently experimented with installing a pond leveler, colloquially referred to as a beaver deceiver, on the ranch due to continuous beaver activity. In deciding whether to attempt the installation, Smith cites her experience with beaver management and the urgency of the situation as motivation. The beaver dam at Elk Meadows was limiting water flow throughout the ranch and preventing it from reaching the cattle. She and her team had tried tearing out the dam, but found it was time-consuming and ineffective as the beaver quickly rebuilt. They also considered trapping, however it seemed unsustainable and not worth the effort, since beaver products are not worth much now.

Smith had heard of the beaver deceiver before and decided to try her hand at installing one herself. The cost of materials for the DIY installation was only around $300 and was able to be installed fairly quickly, says Smith, allowing water to get to the cattle in time. This project also required some experimentation to reach the desired solution. Marina’s team had originally installed a single outtake pipe; however, this still did not provide enough flow to reach the cattle downstream. They decided to adapt their device and install a second outtake pipe right beside of the original one, leading from the same dam. This allowed for increased flow downstream while also maintaining the upstream wetland environment.

Marina’s solution to coexisting with her beaver counterpart seems like a success, and she looks forward to seeing how it holds up in later seasons.

As nature’s engineer comes back to its home in the Madison Valley and elsewhere in Southwest Montana, the potential of their aid in stream and wetland restoration is exciting. Before exiling your local beaver, consider the management practices mentioned above and others, as a way of coexisting and potentially thriving together.