Beavers on the Forest
Within the Black Hills, the industrious beaver once numbered in the thousands and expertly engineered many miles of high-quality riparian habitat.
However, there has been a steady beaver decline over the last 85+ years and today, beaver exist only in a few isolated stretches, small colonies usually found well away from human activity and interference.
Beavers are famous for their engineering skills, as they can quickly construct exceptionally sturdy dams and lodges using the materials found naturally in their environment. They are so good at their jobs that they create entire new ecosystems that benefit many other species. By damming the river and flooding an area, beavers create wetland environments that provide lush vegetation on which other herbivores feed. The aquatic life that thrives in these calm waters also attracts all manner of waterfowl who favor beaver ponds as feeding and nesting grounds. The finescale dace, a native fish to the Black Hills, thrives in this environment as they require wetland habitat to successfully overwinter. Trout species utilize the deep pools and aquatic insects that thrive in beaver dams.
The loss of beaver and their extensive network of dammed waterways has led to the degradation of wetland and riparian habitat throughout the Black Hills.
There are many moving parts as several organizations, volunteers and partners work together to mitigate this loss.
South Dakota and Wyoming State Game, Fish & Parks manage wildlife in their respective states, including beaver. For many years, they have worked with the Forest Service to relocate beavers that have caused safety issues, mainly from cities and towns. Most recently, a young 2 ½ year old male and female were recovered.
The Forest has housed beavers in the past but has never had permanent “temporary” housing facilities. The new pair needed a place to stay until preparations were in place to relocate them to the Forest.
The U.S. Fish and Wildlife Service’s D.C. Booth Historic National Fish Hatchery & Archives in Spearfish, SD was established in 1896 and is one of the oldest hatcheries in the United States. Up to 50,000 trout are propagated onsite and released each year in South Dakota and Montana. When the call came in on the beaver pair, one of the Forest Service wildlife specialist reached out to the hatchery to see if their facilities might be able to temporarily house them for a short duration. Mutually benefiting, they agreed to a trial run and the beaver pair were housed in a bio-secure raceway at the hatchery.
The time came to relocate the beavers to the Forest.
Prior to this, the Forest, many partners and volunteers had already been working to restore beaver habitat by constructing Beaver Dam Analogs, or BDAs.
BDAs are structures built by humans to replicate beaver damming activities for the benefit of wetland and riparian habitat and all the plants and animals dependent on high quality stream habitat. BDAs may be used to attract beavers to a site, or they may also be employed to restore or improve wetlands at sites inappropriate for beavers.
Larger dam structures are constructed by driving wooden posts perpendicular to the stream. Many are located at old beaver dams. The posts are reinforced by weaving willow branches through them and then adding rocks and mud.
BDAs slow down stream flow and create small ponds, control flooding, reduce sedimentation, raise the water table, expand wetlands and provide benefits to many plant and animal species. Additionally, water remains available to wildlife and livestock in the higher elevations for a longer period.
The young beaver pair were relocated to an area with several BDAs in place, along with an old beaver dam that had been rebuilt.
With the beavers in place, the hope is the area will reap from the many benefits they bring, including erosion control and to restore the environment to its former landscape while attracting wildlife, waterfowl, and aquatic life.