Pacific Southwest RegionCalifornia, Nevada and Klamath Basin
'We became beavers'
Partnering with the Scott River Watershed Council, the Service designed a project to simulate what beavers had not been around to do for decades
Dave Johnson, fish and wildlife biologist at the Services’ Yreka office, indicates where juvenile Coho salmon and steelhead find food and shelter near a beaver dam analog structure on Sugar Creek in Scott Valley, California. Credit: John Heil/USFWS
By Susan Sawyer
May 14, 2019
A little over five years ago, a stretch of Sugar Creek in Siskiyou County’s pristine Scott Valley was completely dry. Today it’s a wetland teeming with life.
What caused this landscape to be so completely transformed in a relatively short amount of time? A team of biologists modeling the habits of a rotund rodent with a big overbite – the beaver.
Analogs are rows of posts anchored upright in a creek bed with smaller branches woven in between to help slow the water flow and create a calm backwater, or wetland. This beaver dam analog was constructed in a dry section of Sugar Creek in 2014. Credit: USFWS
Historically, the Scott Valley was referred to as “Beaver Valley” due to the abundance of the lumbering dam builders. However, by the mid-1800s the booming fur trade had wiped out most northern California beaver populations. In the 1930s, land managers began to realize beavers actually helped prevent flooding and stream degradation by creating multi-functional wetlands that attracted a wide variety of wildlife.
So beavers were reintroduced in creek drainages throughout the Sierra Nevada, but that didn’t have much of an effect on the Scott Valley further north.
A beaver glides silently in Sugar Creek near an analog. Beavers were reintroduced to the Sierra Nevada creek drainages in the 1930s as the benefits of their dams became more accepted. Credit: Charnna Gilmore/Scott River Watershed Council
Flash forward to 2014 when the U.S Fish and Wildlife Service’s habitat restoration team in Yreka was contacted by a private landowner who wanted to improve conditions in the dry stretch of Sugar Creek.
Partnering with the Scott River Watershed Council, the Service designed a project to simulate what beavers had not been around to do for decades. In essence, the biologists became the beavers by implementing an innovative technique called beaver dam analogs, developed by Michael Pollock, an ecosystems analyst with the NOAA Northwest Fisheries Science Center.
Analogs are rows of wood posts pounded upright across a creek with willow branches woven between them to simulate a natural beaver dam. These analogs are low cost because heavy equipment use is minimal and they are ecologically beneficial since the design allows for beavers to improve on or abandon them over time as they would a dam of their own design.
A beaver dam analog on Sugar Creek just after completion. The dams allow water and small fish to pass through, while creating a backwater pond that improves plant and wildlife communities. Credit: USFWS
A series of analogs were constructed at the Sugar Creek location, since beavers had once occupied the area. Remarkably, in the fall of 2018, as if answering an advertisement in beaver realty world, a family of beavers moved in and started expanding the analog.
Michael Pollock (left), ecosystems analyst with NOAA Fisheries Northwest Science Center, Jennifer Silveira (retired) and Dave Johnson, biologists with the Yreka field office sample fish in the backwater ponds created by a beaver dam analog on Sugar Creek. Credit: USFWS
Beavers are nature’s eco-engineers and for nearly two centuries were either appreciated or admonished.
These web-footed paddle-tailed lumberjacks are naturally adept at gnawing, felling, dragging and strategically arranging shrubs, large branches and small trees into aquatic architecture that provides a wide range of benefits.
Besides secure lodging for a beaver family, the natural dams and engineered analogs create habitat for birds, mammals, amphibians and fish. Young Coho salmon and steelhead use the slower backwater to feed in and seek shelter from high flows and predators among the mounds of woody debris.
Charnna Gilmore, executive director for the council, praised the benefits of the analog projects.
“The construction not only provided ecological benefit for Coho salmon habitat, but also provided jobs to the community, which is huge in a rural area where work is hard to come by,” Gilmore said. “The watershed council hosts annual field tours to an array of sites, including the beaver dam analogs, for students from local high schools, Humboldt State University and Stanford University.”
In the past five years the U.S. Fish and Wildlife office in Yreka has worked with the council and nine private landowners by funding more than $450,000 and providing technical assistance to construct and maintain 24 analogs at seven different sites throughout the Scott and nearby Colestin Valleys.
Extensive monitoring has been conducted at beaver dam analogs for plants, birds and fish. Ryan Fogerty, supervisory fish and wildlife biologist for the Service in Yreka was impressed with the growth of riparian vegetation and the variety of wildlife observed at Sugar Creek a short time after the analogs were installed.
“The habitat has responded tremendously. The willows and dogwood are booming and so are the migratory birds,” said Fogerty. “Beaver dam analog site monitoring recorded 106 species of birds within 100 yards of the structures. Bird abundance and diversity has been tied directly to ecosystem health.”
If you build it, they will come: A little over a year after the Sugar Creek analogs were completed, a beaver family moved in and began improving on the structures. Credit: Charnna Gilmore/Scott River Watershed Council
About the writer...
Susan Sawyer is the Klamath Basin public affairs officer, covering the Klamath Basin National Wildlife Refuge Complex, Klamath Falls and Yreka Fish and Wildlife Offices. She was raised in the California desert gaining a deep appreciation of the outdoors on family vacations to the Pacific coast,Sierras and Redwood forests.
She has worked in Arizona, Nevada, Montana, Idaho and now Oregon, where she spends her free time landscaping for wildlife, continuing to learn from and about nature and spoiling her animals.
More stories by Susan: