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4 - 70 <br />4.5.12 REFERENCE AREAS <br />• 4.5.12.1 GREASEWOOD SHRUBLAND REFERENCE AREA <br />The Greasewood Shrubland reference area is located within the permit area along Colorado <br />Highway 139, a few hundred feet north of the mine road. ft is triangular in shape and <br />encompasses approximately seven acres. See Figure 4.5-2. <br />This reference area is comparable to the affected area cover but slightly higher in <br />production. See Tables 4.5-2 and 4.5.14. Total cover is 67.7 percent (vs. 74.4 percent <br />affected). Greasewood is the dominant shrub as in the affected area. The reference area is not <br />as disturbed as the affected area as evidenced by a herbaceous understory dominated by <br />western wheatgrass (15.0 percent cover). This perennial, native sod•farming graminoid is also <br />the dominant biomass producer to the affected area. Total estimated production in the <br />reference area ranges from 26.5 g/m2 to 291.8 g/m2 and averages 136.5 g/mZ or 1,216 <br />pounds of herbaceous production per acre compared to 894 pounds per acre compared to 894 <br />pounds per acre for the affected area. See Tables 4.5.3 and 4.5.15. <br />The total shrub density in affected and reference area is similar, 3,386 and 3,483 <br />• individuals per acre, respectively. There are, however, a greater variety of shrub species in the <br />affected area. See Tables 4.5.4 and 4.5.16. <br />Species richness is slightly lower in the Greasewood Shrubland reference area (index = <br />10.20) due to the low number of forb species along cover transects in the reference area (ndex <br />= 0.68). Equitability of the evenness of cover distribution between species is low because of <br />the dominance of two species, greasewood in the shrub stratum and western wheatgrass in the <br />herbaceous stratum. See Table 4.5-5. <br />4.5.12.2 SHADSCALE SHRUBLAND REFERENCE AREA <br />The Shadscale Shrubland reference area, as the affected area, occurs on steep, rocky <br />south-facing slopes on the Torriorthent rock outcrop complex. The reference area is located <br />within the permit area near the mouth of the canyon. The area is rectangular in shape and <br />encompasses approximately four acres. <br /> <br />Mo Volume 1 4.29-96 <br />