2019-04-16_REVISION - C1981019 (3)

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RULE 4 PERFORMANCE STANDARDS Rule 4 Performance Standards 4-73 Revision Date: 4/16/19 Revision No.: MR-200 The initial Permit Application addressed Diversity by using the Shannon Weiner Index to measure the distribution of species within the existing premine vegetation community. Over the early years of SMCRA compliance, this procedure was determined to be problematic for this use as a means to evaluate diversity. Colowyo did not feel comfortable using such a complicated Index, but did so because it was the norm at the time to use this method. Since the initial Permit Application, CDRMS regulations have been revised to allow for the use of comparisons of species composition based on cover between the reclaimed area and the undisturbed vegetation. This method of analyzing diversity was applied to the weighted premine herbaceous vegetation cover data originally sampled and summarized in Section 2.04.10 on Table 2, 1980 Herbaceous Cover by Species. A total of four species with a combined contribution to diversity of 43.4% have been chosen to characterize the premine vegetative community diversity standard. The vegetative species with their contribution to diversity are as follows: Species % Contribution to Diversity (1) Poa pratenensis 22.6% (2) Agropyron Smithii 10.8% (3) Achillea lanulosa 6.7% (4) Stipa viridula 3.3% 43.4% Although Gallium and Lupinus caudatus rank reasonably well in the diversity (composition) scale, they were not included in the diversity goals for reclamation. Gallium is an annual, while Lupinus caudatus is considered toxic to livestock and is most likely a product of overgrazing. Colowyo is interested in reclaiming with vegetation species with equal or superior utility for the postmining land use when compared with the utility of the naturally occurring premine vegetation. Neither Gallium nor Lupinus provides any utility towards supporting the premining land use. Three of the species are perennial cool season grasses and one specie is a perennial forb. All of the species are found throughout the premine area on all soil types and moisture regimes. The grass species all provide the qualities for excellent erosion control and livestock use. All four species of vegetation exhibit high utility towards the premine land use. It is important to note that the species exhibiting the greatest contribution to the premine vegetative diversity is Kentucky Bluegrass, Poa pratensis, which is not considered a native. It exhibits nearly 23% of the composition, over twice that of the next most dominant species, Western Wheatgrass, Agropyron smithii, at nearly 11%. Species diversity for the postmine vegetative community will be determined in the same manner