Dam good! Beavers may restore imperiled streams, fish populations

http://www.eurekalert.org/pub_releases/2016-07/usu-dgb070816.php

Public Release: 8-Jul-2016
Dam good! Beavers may restore imperiled streams, fish populations
Utah State, Eco Logical Research, NOAA, Oregon Dept. of Fish and Wildlife, South Fork Research Publish in Nature's Scientific Reports
Utah State University

Utah State University scientists report a watershed-scale experiment in highly degraded streams within Oregon's John Day Basin demonstrates building beaver dam analogs allows beavers to increase their dam building activities, which benefits a threatened population of steelhead trout.

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When Lewis and Clark made their way through the Pacific Northwest in the early 19th century, the area's streams teemed with steelhead and beaver. But subsequent human activities, including harvesting beaver to near extirpation, led to widespread degradation of fish habitat.

Bouwes says these activities may have also exacerbated stream channel incision, meaning a rapid down-cutting of stream beds, which disconnects a channel from its floodplain and near-stream vegetation from the water table. He notes beavers build dams in the incised trenches, but because of the lack of large, woody material, their dams typically fail within a year.

"It's an ubiquitous environmental problem in the Columbia River Basin and throughout the world." Bouwes says. "It sets a chain of ecological effects in motion that result in habitat destruction, including declines in fish populations and other aquatic organisms."

•••••

When Lewis and Clark made their way through the Pacific Northwest in the early 19th century, the area's streams teemed with steelhead and beaver. But subsequent human activities, including harvesting beaver to near extirpation, led to widespread degradation of fish habitat.

Bouwes says these activities may have also exacerbated stream channel incision, meaning a rapid down-cutting of stream beds, which disconnects a channel from its floodplain and near-stream vegetation from the water table. He notes beavers build dams in the incised trenches, but because of the lack of large, woody material, their dams typically fail within a year.

"It's an ubiquitous environmental problem in the Columbia River Basin and throughout the world." Bouwes says. "It sets a chain of ecological effects in motion that result in habitat destruction, including declines in fish populations and other aquatic organisms."

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