2008-09-29_PERMIT FILE - C1981019A (33)

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RULE 2 PERMITS Woody plant density, by species, for the sagebrush, mountain shrub, and aspen communities is shown on Table 2.04.10-6, Woody Plant Density: Following is a general description of each of the vegetation communities, including various environmental factors contributing to the distribution of the types. The relationships between soil particle size versus soil moisture and their combined effect on vegetation community distribution is illustrated on Figure 2.04.10-1, Environmental Gradient/Plant Tolerance Graph. Sagebrush Community The sagebrush community is characterized by almost complete dominance of the overstory by big sagebrush (Artemisia tridentatel), and snowberry (Symphoricarpos oreophilus), at a density of 2,739 and 1,822 plants per acre, respectively. The measurement of snowberry density is a very subjective measurement whereby large clumps of the species make actual measurement of individual plants along the transect very difficult. Therefore, the given density value is, at best, an approximation of actual density but still provides an indication of relative abundance in the overall vegetative community. For additional woody plant density values by species refer to Table 2.04.10-6, Woody Plant Density. The growth form of the community is characterized by scattered shrubs of low to medium height, rarely exceeding four feet. Numerous areas of open ground exist with various grasses and forbs comprising the understory. The most abundant grasses are western wheatgrass (Agropyron smithii), Kentucky Bluegrass (Poa pratensis), mountain brome (Bromus marginatus), and green needlegrass (Stipa viridula). The most abundant forbs are lupine (Lupinus caudatus), wild onion (Allium spp.), arrowleaf balsamroot (Balsamorhiza sagittata), and yarrow (Achillea lanulosa). During 1980 and 1989 the total herbaceous cover was determined to be 30.9% and 39.71% respectively. For details on cover of individual species refer to Table 2.04.10-2, 1980 Herbaceous Cover by Species and Table 2.04.10-3, 1988 Herbaceous Cover by Species. During 1980 and 1988, total herbaceous production for the sagebrush community was determined to be 436.1 and 825 pounds per acre respectively. According to these production figures, the carrying capacity in animal unit months (AUMs) , assuming 1,000 pounds of air dry forage per AUM at 50% utilization, would be from 0.22 to .41 AUMs per acre. Based on the determination by the Bureau of Land Management of an average production of 0.14 AUMs per acre for the sagebrush type in this area, it is evident that the condition of the sagebrush community with the permit area is good. Grazing has been eliminated from the initial lease area since 1977 and will also be eliminated in the future. Grazing on the permit area addition should be discontinued in 1991 with the construction of wire livestock fencing. The sagebrush community is found throughout the permit area on all elevations, slopes and soils. On portions of the permit area where soil moisture retention and soil depth become limiting to the other vegetation communities, the sagebrush community develops. Snowberry will occur in greater numbers within the community where moisture retention is favorable. For further details on Soil/Moisture relationships in determining vegetation communities refer to Figure 2.04.10-1, Environmental Gradient/Plant Tolerance Graph. Rule 2 Permits 2.04.10-2 Revision Date: 6/23/08 Revision No.: MR-91