Roaring Fork beavers underutilizing landscape, says U.S. Forest Service
U.S. Forest Service/Courtesy photo
American beavers – also known as the engineers of the forest – were once ubiquitous in the Roaring Fork Valley. Today, they’re sparse. But a county/federal partnership to study the creatures aims to support beaver utilization of headwater streams.
The White River National Forest and Pitkin County Health Rivers and Streams gathered habitat data on the native keystone species in the Roaring Fork watershed throughout the summer of 2023.
“We didn’t have a huge sample size, but we feel like we learned enough to take some stabs at things. My impression is that there is some greater capacity on the landscape than what we have at the moment,” said Clay Ramey, a wildlife biologist with the U.S. Forest Service (USFS). “And there are places on the landscape that we might be able to make a little better by putting posts or BDAs, or structures in the creek, that beavers can glom on to, we could put beavers in those places and they might be likely to do well.”
Beavers, which can be a nuisance to property owners, play a vital role in the ecosystem by protecting watershed health. By better understanding where beavers thrive, USFS can support the watershed and subwatershed.
“They improve water tables and increase groundwater storage. They’re great at sediment retention; they happen to flatten out the hydrographs or help with flood attenuation,” said Lisa Taskers of Healthy Rivers. “They help decrease water temperatures, and they increase the extent of riparian and wetland vegetation communities.”
After entering a partnership with Pitkin County, USFS used $50,000 of Healthy Rivers funds to hire two interns over the summer to survey sites within the watershed. The team collected data on foliage, elevation, slope, and occupancy across 119 randomly selected and 15 nonrandom sites across 321,000 acres of land.
“This idea of relative density, which watersheds had a lot and which ones had less, it was hard to kind of put a number on,” said Ramey. “Qualitatively, Woody Creek — just up on the forest — is just not crammed full of beavers right now, for example, where East Maroon Creek is. We still had small sample sizes, which is the bane of everyone’s existence … In my opinion, is that we did get enough to learn enough to get actionable intelligence.”
At the random sites, they identified 47 dams and 6 lodges. Only about half, 53 sites, showed signs of current or past beaver utilization, through damns, chewed trees, and other evidence. The team concluded that the dispersion of beavers in the subwatersheds was wide and sparse.
Vegetation at the sites varied if the site was occupied or unoccupied by beavers. Aspens, willows, and cottonwoods were prevalent on occupied sites. Conifers were more prevalent on unoccupied sites.
“Cottonwoods were only found at 11% of sites, but 77% of those sites were occupied suggesting that where cottonwood exists on the forest, beaver may be coincident,” the report said.
Occupied sites were flatter with wider banks, flatter slopes, and lower elevation, but Ramey said that these high-elevation beavers did not always avoid high elevation.
“They’re not scared of elevation,” Ramey said. “They’ll go to the treeline if there’s food.”
Commissioner Steve Child said he’s noticed beaver activity around Capitol Creek, where he lives.
“I’ve noticed that at the beaver dams up in the forest there, the beavers haven’t seemed to be present,” he said at the work session update on the survey. “They’re all down on private land downstream. They’re still in the creek. They’re just not on Forest Service land right now.”
Tasker and Ramsey said that a long-term goal of this study is to help the public learn to live among beavers, while also identifying potential relocation spots as necessary.
Commissioner Patti Clapper asked if the data could help with potential beaver relocation, acknowledging it was a taboo question.
Ramey said the information could help inform partners like Colorado Parks and Wildlife choose a relocation site based.
“That gets to the sort of relative density idea about habitat, like where’s their habitat?” he asked. ” And so we can at least make better educated guesses about where beavers may be likely to do well.”
Going forward, USFS plans to use the data to protect beavers and promote their activity throughout the watershed.
