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• ~ _ n . n _ 3.0 RESULTS <br />3.1 VEGETATION GROUND COVER <br />Results of the vegetation cover survey aze presented in Tables 3 and 4 for the Survey Area and <br />Reference Area, respectively. Cover data from the 1999 study of the Reference Area are provided in <br />Table 5. The total vegetation cover in the Survey Area averaged 30 percent. Of this, approximately <br />23 percent of the cover was perennial grass, 6 percent was perennial forbs, and 0.5 percent was trees <br />and shrubs. Litter, rock, and bare ground averaged 31, 1.7, and 37 percent, respectively. <br />Table 6 compazes the results for the Survey Area with the Reference Area. The Reference Area had <br />a total vegetation cover of 48 percent in 1999 and 49 percent in 2001. Vegetation cover at the <br />reference site was dominated by perennial grasses, which comprised approximately 29 percent (1999 <br />survey) and 35 percent (2001 survey) of the total cover. Shrubs and trees comprised 9 percent (1999 <br />survey) and 7 percent (2001 survey) of the total cover observed at the Reference Site. <br />Comparison of the species diversity in the Survey and Reference Areas shows that the reclaimed site <br />is dominated by two cool season grasses, western wheatgrass and Arizona fescue (Pascopyrum <br />smithii and Festuca arizonica). In contrast, the Reference Area is dominated by blue gramma <br />(Bouteloua gracilis), a warm season grass, and blackroot sedge (Cares filifolia). <br />• The percent cover of perennial forbs in the Survey Area (6 percent) was slightly lower than the <br />Reference Area (9 percent in 1999 and 7 percent in 2001). Perennial forb species composition did, <br />however, vary between the two sites. The• Survey Area was generally dominated by penstemon <br />(Penstemon sp.), while the Reference Area was dominated by wooly locoweed (Oxytropis sp.) and <br />showy erigeron (Erigeron sp.). Combined cover for annual and biennial forbs in the Survey Area <br />comprised less than 10 percent of the total vegetation cover (approximately 3 percent). <br />Relative cover values for trees and shrubs at the Survey Area was approximately 0.5 percent. The <br />Reference Area had shrub cover values of 9 percent in 1999 and 7 percent in 2001. The Survey Area <br />also had almost twice the incidence of baze ground (37 percent) compared to the Reference Area (18 <br />percent). Discrepancies between the Survey Area and the Reference Area aze to be expected given <br />that the Reference Area has not been subjected to recent mine disturbance. <br />According to the Mine Permit, Picketwire is required to establish vegetation cover that is equal or <br />greater than 90 percent of the Reference Area. Reference Area cover in 2001 was approximately 49 <br />percent in 1999 and 48 percent in 2001. To equal or exceed 90 percent cover of the Reference Area, <br />vegetation cover for the Survey Area would have to equal or exceed approximately 43 percent cover. <br />Total vegetation cover for the Survey Area was approximately 30 percent, or approximately 63 <br />percent of the Reference Area vegetation cover. Although several noxious weeds were observed in <br />the Survey Area, they did not comprise a significant portion of the total vegetation cover (combined, <br />noxious weeds comprised less than 5 percent of the mean relative cover). <br />Several factors may have contributed to a lower vegetation cover at the Survey Area, including soil <br />RevegetationSurveyRepott-RPT(626)RevLdodSeptembn fi, 2001 t~ <br />