HOOK AND FUR
By Bob Brown
Depending who you ask, beavers can be a blessing or a curse. Considered shadow rodents because we don’t hear much about them unless their building activities create some public safety issues, it is a known fact beavers and their dams play an important role in nature’s big picture, and because of the dramatic effects their dams have on surrounding ecosystems, beavers are considered a keystone species.
Today, biologists, scientists and naturalists are embracing the beaver’s ability to create wetlands and other natural habitats.
A group of ecologists and biologists from the NOAA Fisheries Science Center in Seattle are presently involved in an experimental stream recovery operation funded by NOAA Fisheries and the Bonneville Power Administration, using beavers and their dam building skills to re-establish degraded stream habitat in Bridge Creek, a tributary of Oregon’s John Day River. The Columbia Basin News bulletin reported Jan. 10 that the operation has already significantly increased wild juvenile steelhead survival.
This was accomplished by increasing the local beaver population’s ability to maintain long-term and stable dams, thereby reducing canalization and erosion from floods. Bridge Creek beaver dams are often short-lived because they are built within channelized trenches, so when annual flooding occurs, heavy water flow is concentrated on the dams rather than naturally dissipated across a larger flood plain. Consequently, most beaver dams are breached in the first year. This has an impact on both stream habitat and the beaver population.
Initial habitat degradation in Bridge Creek and many other streams in the arid and semi-arid west could have happened in the late 1800s and early 1900s, but regardless how this happened, the important thing now is salmon habitat recovery, said Michael Pollock, ecosystem analyst at the NOAA Fisheries Science Center.
Rather than use conventional, disruptive and expensive stream restoration techniques, researchers built beaver dam support structures in four reaches of Beaver Creek using untreated and stripped lodge pole pine fence posts placed in a wicker weave line at 0.51 meter intervals across the channel and its potential flood plain surface. The structures provided strength to dam’s beavers build themselves, and while beavers readily adopted them, a study found even when beavers do not use the structures; the structures had a positive impact on stream health. So far initial monitoring of steelhead survival is showing improvements.
Analysis by Mary Conner at NOAA Fisheries is showing steelhead survival has increased both in absolute terms to survival in Murders Creek, the control stream. Biologists will continue to monitor both the stream’s health and health of threatened steelhead in the stream. They are also considering expanding the techniques used in this project to the remainder of Bridge Creek. In the meantime, Pollock is fielding phone calls from interested agencies throughout the west, and is in the process of producing a how-to-manual. Also, in the winter of 2014-15 work shops will be held on the techniques used.
“It has been exciting to see the number of agencies interested in using beavers for stream habitat recovery. It is an affordable technique and very effective,” said Pollock.
There are no stream habitat restoration programs similar to that in Oregon in Washington, but the Washington Department of Fish and Wildlife (WDFW) does have a beaver relocation program that removes nuisance beavers from places where they are creating problems to places out of harms way and improve aquifers, wetlands and fis habitat. Three of those release areas are located in eastern Washington’s Yakima, Okanogan and Kittitas counties, said Brian Calkins, a WDFW manager. There is also a private organization that relocates beavers in northeast Washington. House Bill 2381 prohibits the relocation of beavers in western Washington.
Will the WDFW adopt a similar stream habitat restoration program using beavers in the future? The department has not indicated it will or is even contemplating such a program, but the Oregon project is being closely scrutinized. A number of our smaller streams are not in the best of conditions and they need help. Could beavers be the ticket to help turn that situation around? Some environmentalist believe they could
Bob Brown can be contacted at firstname.lastname@example.org.