Ecosystem experiment reveals benefits of natural and simulated beaver dams to a threatened population of steelhead (Oncorhynchus mykiss)

Beaver Dam Analogs (BDA)

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Revitalisation method

The Beaver Dam Analog revitalisation method uses simple, nature-inspired techniques to initiate the beneficial long-term effects caused by natural beaver dams in streams. The BDAs are built cost-effectively using simple tools – usually an axe, shovel, chainsaw and pile driver. No heavy construction machinery is needed. The building materials are sourced from the immediate surroundings.

BDAs are among the most sustainable measures in stream revitalisation. Their construction and maintenance initiates ecological restoration processes leading to the recovery of small and medium-sized streams to a near-natural state.

▻https://www.beaverdamanalogs.ch

Ecosystem experiment reveals benefits of natural and simulated beaver dams to a threatened population of steelhead (Oncorhynchus mykiss)

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Beaver have been referred to as ecosystem engineers because of the large impacts their dam building activities have on the landscape; however, the benefits they may provide to fluvial fish species has been debated. We conducted a watershed-scale experiment to test how increasing beaver dam and colony persistence in a highly degraded incised stream affects the freshwater production of steelhead (Oncorhynchus mykiss). Following the installation of beaver dam analogs (BDAs), we observed significant increases in the density, survival and production of juvenile steelhead without impacting upstream and downstream migrations. The steelhead response occurred as the quantity and complexity of their habitat increased. This study is the first large-scale experiment to quantify the benefits of beavers and BDAs to a fish population and its habitat. Beaver mediated restoration may be a viable and efficient strategy to recover ecosystem function of previously incised streams and to increase the production of imperiled fish populations.

▻https://www.nature.com/articles/srep28581