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(146 shrubs/ac) , and c rymbed wildbuckwheat (110 shrubs/ac) . Minor <br /> shrubs present are rep rted in the cover data. See Table 4. <br /> A total of461 trees are present in the area to be affected, <br /> based on direct count from aerial photographs. Based on cover data and <br /> ground observations of the trees, it is estimated that 90 to 95 percent <br /> of these trees are Uta juniper and the remainder are pinyon pine. <br /> Production <br /> Total herbaceous production of clipped plots in the Sagebrush/ <br /> Cheatgrass Shrubland ranges from 1.8 9/2 m2 to 137.8 g/2 m2 and averages <br /> 40.7 g/2 m2 or 181 Ibs� c. Total grass production is 35.8 g/2 m2 or <br /> 88 percent of the total . Cheatgrass is the major producer with 12.3 <br /> g/2 m2. Other important producers are salina wildrye (9.2 g/2 m2) , <br /> galleta (8.5 g/2 m2) , and Canby bluegrass (3.3 g/2 m2) . Other grass <br /> species contributing to production include Indian ricegrass, slender <br /> wheatgrass AgrzopyAon chycau.Lum, longleaf squ i rrelta i I , needle—and—thread <br /> S.t4pa coma-ta, Sandberg b I uegrass, and six—weeks fescue VuIp4a <br /> octo"o,za. Total forb production is only 4.9 g/2 m2 or 12 percent of <br /> the total . See Table 5. <br /> Species Diversity <br /> Species diversity refers to the evenness of cover distri— <br /> bution among plants, or the relative similarity of cover values. Species <br /> diversity in the Sagebr sh/Cheatgrass Shrubland is low (species diversity <br /> index = 1.00) , represented by 23 species contributing to vegetation cover. <br /> This community may naturally have a low diversity, because of its south- <br /> west aspect and arid habitat. However, grazing by livestock, free—roaming <br /> horses, and wildlife have probably contributed to lower this diversity. <br /> 3.2.2 Shadscale Shrubland <br /> Also occurring on the southv:est—facing slopes of the valley, <br /> but at a higher elevati n and on steeper slopes, is a shrubby vegetation <br /> type of 804 acres dominated by shadscale saltbush. Although shadscale is <br /> typically the most conspicuous saltbush, Gardner saltbush and mat saltbush <br /> A✓u p.Lex colzAuga.ta are also abundant locally. Another halophyte, black <br /> greasewood, is found commonly on small benches where deeper soil permits <br /> moisture accumulation. Other shrub species present include Parry rabbit— <br /> brush Chlzc,,jo-thamnu�j pGALyt., green ephedra, cottonthorn horsebrush, and <br /> broom snakeweed. In addition to these shrubs, scattered throughout the <br /> community are Utah juniper and an occasional pinyon pine. Succulents <br /> present include hedgehog cactus and New Mexican yucca. Herbaceous <br /> cover in the Shadscale Shrubland community is very sparse. Perennial <br /> forbs are especially scarce. Among those present are dwarf fleabane, <br /> basin bahia, rock golde rod, and twinpod. <br /> Perennial g asses are only abundant in habitats having a <br /> low slope and consequent soil accumulation. Species present include <br /> —11— <br />