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~. <br />-3- <br />This cover type comprised 44 acres (2%) of the area to be mined. It <br />was located on intermediate and lower positions of land forms (7,000 <br />to 7,175 feet) below the mountain shrub cover type. It occurred on <br />all aspects of gentle [o moderately sloping topography (3 to 25% <br />slope 1, but favored west-facing slopes on the Eckman Park area. The <br />soils were shallow (2" topsoil and 30" of subsoil), silty in texture, <br />moderately well drained, had moderately low available water capacity, <br />and were subject to moderate erosion hazard. Effective root <br />penetration was poor. <br />Low sagebrush was the predominant species. I[ accounted for most of <br />the cover (33%) and productivity (89%). The other common shrub was <br />rabbitbrush (Chrysothamnus viscidiflorus). Ground cover was composed <br />mostly of grasses with only a few annual forbs. The grasses were <br />prairie juuegrass (Koleria cristana), slender wheat grass (Agropyron <br />trachvlcaulum), foxtail barley (Hordeum jubatum) and needlegrass. <br />Two shrubs, 4 grasses and a single annual forb (7 total) comprised <br />the low sagebrush cover type. The index of diversity value was <br />0.423. The average litter cover was 23`/, and the canopy cover for <br />grasses, forbs and shrubs was 9, 1, and 35 percent respectively, for <br />a total cover of 68 percent. Total production for [he low sagebrush <br />type was 920 pounds per acre (99, 3 and 818 for grasses, forbs and <br />shrubs respectively) and the estimated carrying capacity for normal <br />years was 0.24 AUM's per acre. Based on expected production for <br />unfavorable and favorable years the estimated ranges for forage <br />production and carrying capacity were 300 to 800 pounds per acre and <br />0.15 to 0.40 AU"t's per acre respectively. <br />(4) Treated (Sprayed) Sagebrush <br />This cover type comprised 84 acres (5%) of the area [o be mined. <br />Generally its physiographic and soil characteristics were similar to <br />the big sagebrush range site with some similarity to the aspen type. <br />The average slope however, was less than SY,. Species composition <br />differed from the big sagebrush type primarily because it had been <br />sprayed. In the treated area, big sagebrush and the forb species <br />were considerably less important than in the sagebrush type. <br />However, sagebrush remained [he predominant shrub species in the <br />treated area. Smooth brome (Bramus inermis), was the predominant <br />ground cover species (40% of the composition). Other grasses were <br />bluegrass, desert wheatgrass (Agropyron desertorum), and needlegrass. <br />The forbs were peavine (La[hyrus spp.), American vetch, and an <br />undetermined forb. One shrub, 5 grasses, and 3 forbs (9 total) <br />comprised the treated big sagebrush type. The index of diversity <br />value was 0.720. The average litter cover was 44% and [he canopy <br />cover for grasses, forbs, and shrubs was 25, 7, and 15 percent <br />respectively, for a total cover of 91 percent. Total production for <br />the treated sagebrush type was 1,861 pounds per acre (829, 163 and <br />