Ecosystem Engineers: Wyoming Beavers Deployed to Repair Wetlands

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Crews of furry, buck-toothed trail crews may be the future of repairing streamside erosion. Beavers, and their penchant for building dams using sticks, mud and stones, have been effective in helping vital wetland areas retain and purify water for centuries. In fact, many of the flat, willow-dominated landscapes in valleys across North America today were formed by the trickledown effects of beaver dams.

The unique abilities of this keystone species are being put to good use in Wyoming where, since 2018, the state’s Game and Fish Department has relocated more than 80 “nuisance beavers” from private land to areas near Cody to help repair damaged wetlands. The department completed construction of a temporary holding facility for beavers last month to expand the program’s capacity, according to an Oct. 19 press release.

“Game and Fish routinely use beavers to improve habitat in Wyoming and this facility will grow the capacity for habitat enhancement using beavers in the northwest portion of our state,” said Jerry Altermatt, Cody Region terrestrial habitat biologist.

The semi-aquatic rodents are expert dam builders, and their industrious behavior helps repair eroded streambeds by trapping sediments and slowly raising water levels. Plants such as willows—which provide food and shelter for moose, mule deer and numerous other species—benefit from the enhanced water retention in the wetlands adjacent to streams and rivers.

One study from 2020 even shows that areas where beaver dams have created wetlands are less prone to burning when wildfires rip through them.

Beavers are not, however, particularly well-suited to coexist too close to human resources. The same behaviors that repair wetlands can flood crops, roads and other structures, often leading landowners to rid their property of the animals. It’s these nuisance beavers that Wyoming’s Game and Fish traps and relocates.

The department identifies areas in need of riparian restoration and aims to relocate a breeding pair and its offspring to achieve the highest probability of success. “Transplanting a family group increases the likelihood that the beavers will stay in the transplant location and establish successfully,” Altermatt said. “Sometimes this process can take time as the beavers are often caught one at a time.”

The Fish and Game program uses a specialized trailer to house trapped beavers before relocation, however the small spaces can hold only a few beavers for short time periods. The new facility quadruples the department’s holding capacity and affords more time to relocate the animals.

“The facility provides a secure location to house beavers and allows for more flexibility for pausing and resuming trapping efforts as necessary to allow trap-shy beavers to settle down,” Altermatt said, noting that the program has created at least eight successfully established colonies so far.

The U.S. Forest Service estimates that as many as 400 million beavers lived in North America prior to the arrival of European settlers in the 16^th century. Beaver pelts quickly became popular and lucrative fashion statements, and trappers nearly annihilated the population between 1600-1900. Due to better wildlife management practices and a decline in pelt popularity, the Forest Service estimates that North American beavers have rebounded to between 6 million and 12 million.

As such, Wyoming’s beaver program and similar initiatives can have twofold impacts: sustaining beaver populations and repairing damaged wetland landscapes.

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