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The reference area pasture is in good ecological condition. Soil erosion is minimal, there are no <br />significant gullies or rills, and very little bare ground. Desirable plant species composition is diverse, <br />which provides a robust vegetation stand able to resist some variability in irrigation water application <br />or grazing regimes. Some drier areas tend to be dominated by weedy annual forbs, gunweed, and <br />occasionally cheatgrass, but these areas make up only a small fraction of the reference area, and <br />are typical of flood- irrigated pastures in the Nucla area. <br />The reference area vegetation is representative of the pre -mine irrigated pasture type in the permit <br />area. Irrigated pastures in the permit area were originally mostly dominated by native sagebrush <br />shrublands or pinyon juniper woodlands. When converted to irrigated pasture, trees and shrubs <br />were typically removed mechanically or by flooding, and plant species desired for livestock forage <br />were seeded including perennial grasses and forbs such as alfalfa and clover. These irrigated <br />pastures are intended primarily to provide winter forage for livestock, and secondarily to provide cut <br />hay. Uneven application of flood - applied water is typical because of variable terrain, and wet areas <br />soon become dominated by wetland grasses and forbs, and sometimes Russian -olive or emergent <br />wetland plants such as cattail or bulrushes. Weedy annual forbs and cheatgrass typically become <br />established on drier sites, and many become dominant in disturbed areas. The species composition <br />and ecological condition of pre -mine irrigated pastures in the permit area varies widely depending <br />on irrigation water availability and management history. <br />A comparison of the 2007 vegetation data in the reference area with pre -mine studies conducted <br />by Peabody Coal Company in 1987 and WFC in 1999 (in Attachment 2.05.4(2)(e) -5) and <br />Attachment 2.05.4(2)(e) -2) shows that the reference area vegetation is similar to pre -mine <br />vegetation in the irrigated pasture type. The 1987 total vegetation cover was 71.8% and dominated <br />by perennial graminoids, mostly seeded pasture grasses with Kentucky bluegrass the most <br />dominant, all similar to the 2007 reference area measurements. See Table 2.05.4(2)(e) -3. Mean <br />herbaceous production was measured at 2,823 lb/acre, similar to the 2007 reference area mean. <br />In 1999, estimates of mean cover in 2 subjectively selected irrigated pastures (deemed <br />representative of "typical' conditions) were also similar, showing perennial grass cover of 44.5 %, <br />perennial forb cover of 33.3 %, and total desirable vegetation cover of about 79 %. Annual <br />herbaceous production was estimated at 4,153 lb/acre. The 1999 mean is higher than the 2007 <br />mean measured in the reference area, but the irrigated pasture type has been demonstrated in 1987 <br />and 1999 sampling to be extremely variable in production depending on site factors, management, <br />(June 2013 MR 86) 2.05.4(2)(e) - 29 <br />MK-S(P <br />igpProved <br />,Z13 Jun , 2 013 <br />