REP50491 - Laserfiche WebLink

Home Browse Search

RESULTS Field data from the 2002 revegetation monitoring studies at the Colowyo Mine are presented in Appendix 1, Tables 1 through 21. Seedling density data from areas seeded in year 2001 are summarized in Table 22. Cover, woody plant density, herbaceous production, species density, and relative cover by lifeform data are summarized in Tables 23 through 25. Sample adequacy evaluations are presented in Table 26. Figures 8 through 11 depict percent foliar cover, woody plant density, species density and relative cover by lifeform. Appendix 2 contains a tally of all plant species present in each area sampled in 2002. Appendix 3 comprises a list of seed mixes used in the areas sampled in 2002 as well as the conversion tables used in Table 22. Appendix 4 presents photographs from the areas sampled for cover, woody plant density, and herbaceous production in 2002. • DISCUSSION Climatic Conditions 2002 was a very dry year in the vicinity of the Colowyo Mine. Figures 1 and 2 show that eleven of the 12 months preceding the late July/early August sampling in 2002 were below average, with the often critical month of May having experienced almost no precipitation at all. 2001 had also been a dry year, so little carry-over moisture was likely present to ameliorate the 2002 dryness. Cumulative measures of precipitation over the previous 12, 6, and 4-month periods (Figures 3, 4, and 5) all show clearly that 2002 was a very dry year. 2002 was a cooler than average year (Figure 6) but a slightly windier than average year (Figure 7). Cover The performance standard for cover was calculated as 90% of the weighted average of herbaceous all-hit cover from the two Reference Areas. Weighting was applied in proportion to the extent of the Sagebrush and Mountain Brush vegetation types in the baseline vegetation sampling. Figure 8 depicts the allowable cover, i.e. the cover that can count towards satisfaction of the cover performance standard. Cover that is 5