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• sagittata) (3.0 percent cover; 70 percent frequency), and western wheatgrass (Agrooyron <br />smithii) (1.2 percent mean cover; 70 percent frequency). These four species accounted <br />for more than 75 percent of the cover (fable I). As a life form group, perennial forbs <br />accounted for 22 percent of the Total cover. The two subspecies of sagebrush accounted <br />for approximately 60 percent of the total cover. Mean total vegetation cover was ap- <br />proximately 23 percent and cover by bare soil was I I.5 percent. <br />Total production (excluding production by shrubs) was 56.08 g/m2. Western wheat- <br />grass (19.88 g/m2) and arrowleaf balsamroot (20.63 g/m2) accounted for the majority of <br />the Total biomass (Table 2). Total production was divided almost equally between the <br />perennial grasses and perennial forbs. Annual and biennial forbs provided only a minor <br />amount of the total biomass. <br />Total shrub density along the tie across haul road was 25,500 shrubs per hectare <br />(10,324 per acre). Of this total, approximately 75 percent were Rothrock big sagebrush <br />(fable 3). The high schrub density is mostly attributable to the growth form of Rothrock <br />big sagebrush. As mentioned above, Rothrock big sagebrush tends to be a low-growinq <br />shrub and occurs as numerous small individuals. This characteristic can be seen in the <br />height class data. Of nearly 19,000 individuals per hectare, almost all of them are less <br />than 0.25 meters in height. Mean density for mountain big sagebrush was 6,280 individ- <br />uals per hectare (2,542 per acre). <br />There were 55 voscular plant species observed growing in the mixed sagebrush <br />shrubland type along the realigned portion of the tie across haul road (Table 4). All of <br />these species are typical of western Colorado sagebrush shrublands. None of the species <br />are threatened or endangered. <br />Mixed Sagebrush shrubland Reference Area <br />The vegetation in the mixed sagebrush shrubland reference area is very similar to <br />that occurring along the realigned tie across haul road right-of-way. The major differ- <br />ence is that Rothrock big sagebrush is more prevalent and mountain big sagebrush is <br />somewhat less prevalent than on the realigned tie across haul road site. Total vegetation <br />cover, total production, and species composition are comparable on the two areas. <br />r • <br />