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• Sagebrush - 2 Tvne. The sagebrush-2 vegetation type represents remnants of native rangeland <br />that has not been converted to the more characteristic intensive agricultural land uses in the area. <br />This type occurs on toe slopes of mesa sides with slopes ranging 5 to 30 percent. Sagebrush <br />ranged in height 3 ft. to 9 ft. with and average height of 6 ft. Associated with the sagebrush were <br />the shrubs rubber rabbitbrush and four-wing saltbrush. Understory plants are typical of rangeland <br />plants found in the sagebrush-1 type except where irrigation water had run onto the site. In these <br />situations, the understory is dominated with Russian knapweed. <br />Total vegetation cover (first hit) for the type averaged 56 percent, with bare ground at 7.6 percent, <br />litter at 32.8 percent, and rock outcrop and rock fragments at 3.6 percent (Table 2.04.10-24). <br />Lichen and moss accounted for 0.2 percent of the mean cover. The shrub component dominated <br />with 45.4 percent cover and the annual grass component at 6.5 percent cover. Perennial grasses <br />and forbs at 1.6 and 1.6 percent cover, respectively. Consistent with the type designation, Basin <br />big sagebrush (Artemisia tridentata ssp. tridentata) had the highest perennial species cover at <br />36.9 percent (85 percent frequency), followed by rubber rabbitbrush with cover at 8.5 percent (35 <br />percent frequency) while the ubiquitous invader of sagebrush rangelands, cheatgrass Anisantha <br />tectorum) had a cover of 6.5 percent (44 percent frequency). Russian knapweed had a cover of <br />• 0.2 percent (10 percent frequency) where irrigation runoff was present. The remaining species <br />generally contributed less than one percent cover to the mean total vegetative cover. <br />Total herbaceous production (including shrubs) toialed 138.5 gJm2 or 1236 pounds/acre (Table <br />2.04.10-25). Herbaceous production without the shrub component totaled 19.2g/m2 or 171 <br />pounds/acre. The perennial shrub component contributed the highest value at 119.3 g/m (1065 <br />pounds/acre) followed by annual grass at 10.2 g/mZ (91 pounds/acre). While the contribution of <br />perennial grasses and forbs was (2.2 and 6.8 glmZ, respectively). In order to sample the perennial <br />species at the peak of their production, many of the earlier maturing annual species were <br />senescent or were already gone from the stand. Thus the annual grass production is likely higher <br />than stated. <br />Woody plant density measurements in 1999 differed from 1987 as suffruticose species were not <br />measured consistent with Guidelines for Compliance with Land Use and Vegetation Requirements <br />for Coal Mining. Succulents were also not included in the density calculations. Mean density for <br />the type was 37.7 stems/50m2 or 3,015 stems/acre (Table 2.04.10-26). Sagebrush dominated <br />• (REVISED 8/15/00) 2.04.10 - 67 <br />