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iii iiiiiiiiiiiiiiii <br />999 <br />• 6.2 Biology Monitoring <br />6.2.1 Terrestrial Vegetation <br />Pursuant to BLM and Colorado DMG requirements, vegetative production, and percent crown <br />cover were sampled in 1991 through 2001 for native undisturbed areas. <br />Circular Random Plots: The total 2001 grass and fort production is shown on Table 6-19 <br />for 1992 through 2001. July's total production was the lowest on record as a result of less <br />than average precipitation for the second year and a record low precipitation for the month <br />of June. July open plots, when compared to July caged (to exclude grazing) plots, indicate <br />an insignificant difference of +12% for open plots. No significant usage by cattle or horses <br />• on the mine site in the spring and summer months of 2001 were noted. Herbaceous <br />production (grass and forts) per species is shown on Table 6-20 with western wheatgrass, <br />needlegrass, June grass, and Phlox hoodii, the most productive species. Figure 6-18 <br />illustrates 1992 through 2001 production for July open and caged. In 2001 the grass seem <br />to have endured the drought and freezes better than the forts. Percent cover data for July <br />caged compared to July open indicated insignificant differences (see Figure 6-19). The <br />percent cover of grass was slightly higher in the caged plots even though grazing was restricted <br />and bare, rock, and litter was slightly higher as a result of the extreme conditions. Shrubs and <br />trees were similar for open and caged plots. <br />• 86 <br />