2022-10-26_PERMIT FILE - C1981041

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• Colorado Division of Minerals and Geology expressed concerns that the original reference area did not represent the greasewood shrubland vegetation community that had been disturbed at the mine or the greasewood community that would be reestablished during reclamation efforts. Further, the area that encompasses the original greasewood reference area had a history of human disturbance. The new greasewood reference area was selected to address these concerns. A comparison of the two reference areas is in order to evaluate their characteristics in light of the concerns that Jed to the selection and sampling of the new greasewood reference azea. These comparisons are not intended as a quantitative evaluation of the compazability of the two reference areas, but as a general indicator of the nature of the two communities, with similarities and differences identified. Vegetation Cover In 1983, the total vegetation cover of the original greasewood reference area was 50.9 percent. Three lifeforms were represented in the cover sampling. Graminoids accounted for 7.7 percent total cover, forbs 17.8 percent, and shrubs 24.9 percent. Non-vegetation cover accounted for 49.1 percent. A small cryptogamic component was present (0.6%). The dominant individual species was Sarcobatus vermiculatus with ] 9.5 percent mean cover, followed by Sueda fruticosa, a perennial forb (12.6% mean cover), Distichlis spicata (5.6%), Chrysothamnus nauseosus (5.2%), Lepidium perfoliatum (3.3%), and Bromus lectorum with 2.0 percent mean cover. • This year, the new greasewood reference area revealed total vegetation cover of 49.07 percent. Four lifefomLS were present in the cover sampling. Of those, graminoids accounted for 35.47 percent total cover, forbs 0.93 percent, succulents 0.13 percent, and woody plants 12.53 percent total cover. Litter, bare ground and rock provided 42.27 percent cover. A significant cryptogamic crust was present and accounted for 8.67 percent cover. The dominant species was Bromus tectorum, accounting for 28.93 percent total cover. Sarcobatus vermiculatus provided the second highest cover at 8.13 percent. Hilaria jamesii and Gutierrezia sarothrae also provided significant cover of 4,67 and 2.27 percent, respectively. By overall comparison the two reference areas contain the same amount of vegetative cover. Dominant species differ in the two areas, likely attributable to physical and historic factors, including slope, aspect, moisture regime, parent material, and human manipulation. The dominance of Sarcobatus vermiculatus in the original reference area reveals a more mesic moisture regime and higher cation concentrations in the soils of the area. The new greasewood reference area is situated higher elevationally, with significant moisture being provided by precipitation and occasional overflow of the ephemeral drainage. The dominance of Bromus tectorum in the new greasewood reference area is also indicative of the more xeric moisture regime as well as the more open character of the community, which provides niche space for the opportunistic Bromus. • The original greasewood reference area cover sampling encountered one annual grass (Bromus tectorum) and two perennial grass species (Distichlis spicata and a trace of Poa -~-