When habitat biologists take on a stream restoration project, it’s usually because that stream has been damaged over time; erosion and down-cutting are a few examples. Biologists restore streams in a number of ways; sometimes it involves using heavy equipment. But sometimes you can give mother nature an assist. Beaver have long been known as the kind of “engineers” of sorts, that can help restore a stream by building dams that help disperse flooding, and moderate stream temperatures by retaining water during high flows and releasing water into streams when flows are low.
But sometimes beaver aren’t…eager to inhabit an area being restored, or have left that area completely. That’s where these come in. Beaver dam analogs (BDA’s), are man-made structures that mimic the function of a natural beaver dam. Recently, the Wyoming Game and Fish Department participated in a workshop hosted by The Nature Conservancy at the department’s Amsden Creek Wildlife Habitat Management area near Dayton, that explained the effectiveness of BDA’s, and then a few structures were installed to entice beaver to recolonize a stretch of the creek.
One of the more appealing aspects of building BDAs is that the materials used to make them can often be found onsite; willows, poles, branches and other materials can be cut and assembled in a creek or stream at a much lower cost than bringing in heavy equipment or expensive materials. The only part that lacks appeal…is that it’s fairly labor intensive. The Game and Fish and various partners have used BDA’s in previous projects--these structures can boost the water table, stream channels have been down-cut, build new floodplains, induce stream meandering, promote new woody vegetation, and create an inviting place for beaver to set up home in by creating deep water habitat that reduces the risk of predation. Once an actual beaver dam is built, the benefits include extended late season stream flows, more lush forage and cover for terrestrial species, and fish species benefit by the addition of instream cover and channel complexity-more stream-side vegetation available to grow terrestrial bugs and provide shade over the channel to benefit fish.