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THE USE OF BEAVERS IN RIPARIAN/AQUATIC HABITAT RESTORATION IN A COLD DESERT, GULLY-CUT STREAM SYSTEM: A CASE HISTORY LARRY L. APPLE U. S. DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT P. O. BOX 1869 ROCK SPRINGS, WYOMING 82901 ABSTRACT A study project was initiated in 1981 to develop techniques for restoring and reestablishing degraded riparian and aquatic habitat on two perennial streams in southwestern Wyoming. The major objective was to utilize primarily "natural" systems to restore the habitat rather than use labor and capital-intensive artificial methods. One study area was fenced to exclude livestock grazing and one was left unfenced. The riparian vegetation was rested and beaver were reintroducted to the fenced study area; the beaver returned on their own to the unfenced study area. Aspen trees were delivered to the sites of beaver activity on both streams because large materials for stable dam building was not present. The newly built beaver dams are trapping sediment, reducing stream velocity, and locally elevating the water table, thus allowing for the reestablishment of willow and other ripar- ian plants in an expanded riparian zone, which stabilizes the stream banks, and improves aquatic habitat. Riparian zones in the arid west, while representing less than 1% of the total land surface, are typically the focus of human activity, as well as being vital to the well-being of many wildlife and plant species. On land, the riparian or stream-associated vegetative community is probably the single most productive wildlife habitat type benefiting the greatest number of spe- cies (Winegar 1977), with the Willow-grass community producing the greatest amount of total vegetative biomass (Hansen 1977) in the cold desert environ- ment. Unfortunately, many livestock grazing programs to date have not been managed for the maintenance or improvement of this community. Grazing prac- tices have not typically recognized the importance of a healthy, vigorous, riparian area to the long-term stability of the rangelands. The loss of a complete young willow age class structure, followed by the subsequent loss of even the older willow plants are indicators of declining community structure, resulting in accelerated streambank erosion and a lowering of the riparian 29