Using beavers to improve our Environment

building a beaver dam analog structure GYA BRAT Story Map Beaver Release Transporting Beaver

Beaver – History

Beavers have long played a roll in creating intricate ecosystems. “We look out on the landscape and view rolling vistas and single-thread streams and have no comprehension of how much things have changed from the past,” said Lee Mabey, Caribou-Targhee National Forest Fish Biologist. Through their dams, beavers originally formed much of the wide, flat and willow dominated landscapes located on valley bottoms we see today.

In his book Eager: The Surprising, Secret Life of Beavers and Why They Matter, Ben Goldfarb describes the function of beavers as “creating a network of spaghetti, with ribbons of water intertwining, separating and spilling off your plate.” It’s this unique network of water flow that creates superb habitat for fish and other aquatic species.

It’s quite a simple concept, areas with beaver dams have more diversity. Beaver dams spread out water, creating a habitat rich with vegetation, sunlight and significant nutrients. These flood plains provide extensive biomass needed to support the entire wildlife community. The dams also improve degraded watersheds and enhance water quality.

So, with all these benefits what happened?

It's estimated before European’s came to North America, beaver populations ranged between 60-400 million. Due to its popularity for hats and other materials, trappers decimated the population between 1600-1900. After beaver hats and coats went out of style, the population slowly began to rebound. Scientists now estimate that populations are now between 6-12 million (

Our perception of the beaver is often skewed by our own personal experience. For the county maintenance worker or farmer trying to make an agricultural living, a nuisance beaver can be costly; plugging culverts, flooding roads and disrupting irrigation. For a scientist, a beaver is a keystone species, reforming the land and improving the ecosystem. While the benefits are real (reducing erosion, improving water quality, removing heavily sedimented waters and improving ground water recharge) so are the challenges.

How do we balance the benefits with the costs?

Balancing the nuisance aspect of beavers with their restoration abilities is the question members of the Greater Yellowstone Coordinating Committee (GYCC) wanted to address. In 2018, the fisheries, climate change adaptations and hydrology subcommittees submitted a proposal to the GYCC to develop a Beaver Restoration Assessment Tool (BRAT). The goal was simple, with the assistance of Utah State University create a computer model with associated GIS files that identifies the low hanging fruit where beaver will have the least impact on humans and the greatest impact on restoring natural processes.

GYCC- What is it?

The Greater Yellowstone Area (GYA) is a unique and special place. It’s the heart of a landscape critical for the survival of many species in the west due to its location and large swath of 15 million acres of public lands, the GYA is geographically contiguous, ecologically interdependent and unalterably linked. To facilitate the flow of information, the GYCC was established in 1964. Since then it has provided money for various project improving the environment. With the National Park Service, US Forest Service, US Fish and Wildlife Service and the Bureau of Land Management working together to pursue opportunities to cooperate and coordinate land management activities in this area.


The Greater Yellowstone BRAT was finalized in late 2019 and provides benefits to multiple states and federal agencies. Both private and public entities can use it to identify areas where the existence of beavers make sense in our modern world. A 100% reintroduction of beavers is not feasible with how we now exist on the landscape. However, with this model, we can improve stream function and fish and wildlife habitat in low populated areas. The final model and data are free to any user group who wants it.

Utah State summed it up nicely “With the development of the GYA BRAT model, the scope of what is possible in terms of partnering with beaver for restoration is now clearly defined and mapped…The GYA BRAT model helps build realistic expectations about what beaver dam-building may achieve locally on a given stream, and also helps scale-up those expectations at the watershed and regional levels.”

Utah State University compiled a beautiful visual story map depicting the greater Yellowstone BRAT project.

For those that would like access to the full GIS based outputs of the GYA model Contact Lee Mabey at or search Greater Yellowstone Area BRAT. The model can be ran by Utah State anywhere the base data is available. Other tools are also available as to how to encourage the dam-building habits of beaver to restore areas degraded by lack of beaver dam effects.