2017-02-03_PERMIT FILE - C1980004 (2)

Home Browse Search

2.04.10 Vegetation Information Environmental Quality Vegetation Guideline No. 2, March 9, 1979. Desert Princes plume did not occur in the cover transect. There are no state or federally listed threatened or endangered plan species present on the study site. REFERENCE AREAS GREASEWOOD SHRUBLAND REFERENCE AREA The Greasewood Shrubland reference area is located within the permit area along Colorado Highway 139, a few hundred feet north of the mine road. It is triangular in shape and encompasses approximately seven acres. See Figure 4.5-2. This reference area is comparable to the affected area cover but slightly higher in production. See Tables 4.5-3 and 4.5-15. Total cover is 67.7 percent (vs. 74.4 percent affected). Greasewood is the dominant shrub as in the affected area. The reference area is not as disturbed as the affected area as evidenced by a herbaceous understory dominated by western wheatgrass (15.0 percent cover). This perennial, native sod - farming graminoid is also the dominant biomass producer to the affected area. Total estimated production in the reference area ranges from 26.5 g/m2 to 291.8 g/m2 and averages 136.5 g/m2 or 1,216 pounds of herbaceous production per acre compared to 894 pounds per acre for the affected area. See Tables 4.5-3 and 4.5-15. The total shrub density in affected and reference area is similar, 3,386 and 3,483 individuals per acre, respectively. There are, however, a greater variety of shrub species in the affected area. See Tables 4.5-5 and 4.5-17. Species richness is slightly lower in the Greasewood Shrubland reference area (index = 10.20) due to the low number of forb species along cover transects in the reference area (index = 0.68). Equitability of the evenness of cover distribution between species is low because of the dominance of two species, greasewood in the shrub stratum and western wheatgrass in the herbaceous stratum. See Table 4.5-6. SHADSCALE SHRUBLAND REFERENCE AREA The Shadscale Shrubland reference area, as the affected area, occurs on steep, rocky south -facing slopes on the Torriorthent rock outcrop complex. The reference area PR -02 2.04-66 10/12