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Letterman's needlegrass (Stipa lettermanii), with 12.3 %, 6.6 %, 6.2 %, 4.9 %, and 4.7% average cover, <br />respectively. With regard to diversity, the Mountain Shrub Reference Area exhibited 6 perennial grasses <br />with between 3% and 50% relative cover (Table 2). Total relative cover for all forbs excluding noxious <br />weeds in the Mountain Shrub reference area was 14.8 %. <br />A total of 27 plant taxa were observed in this reference area (Table Al). Current annual herbaceous <br />production across the area averaged 630.0 pounds per acre in 2009 with perennial grasses the dominant <br />category (Table 3). Ground cover in the Mountain Shrub Reference Area (Table 1 and Chart 1) consisted <br />of 61.3% live vegetation, 0.7% rock, 33.2% litter, and bare soil exposure of 4.9 %. Perennial cover <br />across the unit averaged 54.7% with annual and biennial cover averaging 6.7 %. Dominant taxa were <br />big sagebrush, bluegrass, mountain snowberry, and slender wheatgrass (Agropyron trachycaulum), with <br />10.6 %, 8.6 %, 7.5 %, and 6.3% average cover, respectively. With regard to diversity, the Mountain <br />Shrub Reference Area exhibited 5 perennial grasses with between 3% and 50% relative cover (Table 2). <br />Total relative cover for all forbs excluding noxious weeds in the Mountain Shrub reference area was <br />9.1%. <br />3.2.2 Sagebrush Reference Area <br />The Sagebrush Reference Area is comprised of approximately 4.7 acres of gently to moderately <br />sloping vegetation that has a predominately northerly aspect. Plates 7 and 8 show site conditions for <br />2008 and 2009, respectively. This reference area is located on a gently sloping ridge north of the <br />Administration / Facilities Area (Maps 5 and 6). Current annual herbaceous production across the area <br />averaged 608.2 pounds per acre in 2008 with the dominant categories being perennial grasses and <br />annual grasses (Table 3). Ground cover in the Sagebrush Reference Area (Table 1 and Chart 1) <br />consisted of 57.9% live vegetation, 2.4% rock, 25.6% litter, and bare soil exposure of 14.2 %. Perennial <br />cover across the unit averaged 34.7% with annual and biennial cover averaging 22.8% and noxious <br />weed cover with 0.1% cover. Dominant taxa were cheatgrass, big sagebrush, Japanese brome (Bromus <br />japonicas), prairie junegrass (Koeleria macrantha), and western wheatgrass, with 14.1 %, 9.6 %, 8.0 %, <br />4.9 %, and 4.3% average cover, respectively. With regard to diversity, the Sagebrush Reference Area <br />exhibited 4 perennial grasses with between 3% and 50% relative cover (Table 2). Total relative cover <br />for all forbs excluding noxious weeds in the Sagebrush reference area was 6.9 %. <br />A total of 30 plant taxa were observed in this reference area (Table Al). Current annual herbaceous <br />production across the area averaged 760.3 pounds per acre in 2009 with perennial grasses and annual <br />grasses the dominant categories (Table 3). Ground cover in the Sagebrush Reference Area (Table 1 and <br />CEDAR CREEK ASSOCIATES, Inc. Page 17 Rio Tinto Energy America - Colowyo Mine <br />2009 Phase III Bond Release Evaluation - Year 2 <br />