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VI. RIPARIAN COMMUNITY RIPARIAN COMMUNITY: GENERAL DESCRIP'fiON Though one of the least common vegetative communities in the vicinity of the West Elk Mine (MCC, 1996), riparian communities generate much interest due to their purported value as refugia and habitat for significant wildlife species. Wright Water Engineers (1996) surveyed the Sylvester Gulch drainage in 1995 for the presence of riparian communities. The definition of riparian communities was much debated prior to this specific survey effort, with the U.S. Forest Service (USFS) embracing a very broad definition of what a riparian community encompassed. Riparian azeas were defined by USFS as azeas of jurisdictional wetlands plus any area which had vegetation typical of wetter azeas than the surrounding vegetation (WWE, 1996). This definition is in conflict with the more mainstream definition of riparian areas and riparian communities found in the scientific literature (Mitsch and Gosselink, 1986; BLM, 1993; Platts, et al, 198'7). For the purposes of this vegetation study, a relatively narrow interpretation of a riparian vegetation community was employed. First, the area had to exhibit vegetation characterized as hydrophytic or dependent on large amounts of adjacent surface or subsurface water. The riparian community had to be within or immediately • adjacent to a surface water channel. Third, the community had to have evidence of periodic influence of surface water flow. Based on these criteria, and most importantly, visual observation of the Sylvester Gulch study area through aerial photography and on-the-ground reconnaissance, the riparian community within the Sylvester Gulch study area was identified as a narrow linear band within and immediately adjacent to the Sylvester Gulch drainage. The riparian community is discontinuous, even along the Sylvester Gulch drainage. Within the study area the riparian community reaches its northern extent (where it grades into the oakbrush community) immediately east of the subsoil stockpile at the access road switchback. The riparian community continues in a lineaz band south, for approximately 3500 feet to the first confluence of two branches of Sylvester Gulch. The riparian community continues up the east branch of Sylvester Gulch for approximately 2000 additional feet. The riparian community does not continue further south on the main branch of Sylvester Gulch within the specified study azea. The width of the riparian community ranges from 30 to 300 feet (at the confluence of the lowest branches of Sylvester Gulch). The riparian community intergrades into the oakbrush community at south and west slopes outside the immediate drainage particularly toward the north end of the drainage. At higher elevations, the riparian community intergrades into both the aspen . community on terraces and sideslopes, and the Douglas fir community on mesic north and northwest facing slopes adjacent to the drainage. On flat areas (presumed alluvial terraces) the riparian community may adjoin anthropogenic dry meadows. The riparian -16-