2015-10-13_REVISION - C1981014 (18)

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shrubs was the fourth most dominant plant form, contributing 1.05% of the total plant cover and 3.96% of the total relative plant cover. Noxious weeds was the fifth most dominant plant category, contributing 0.05% of the total plant cover or 0.18% of the total relative plant cover on this site. Blue Grama as the most dominant plant species encountered, contributing 9.00% of the total plant cover or 33.94% of the total relative plant cover. Russian Thistle, was the second most dominant plant species,, contributing 4.05% of the total plant cover or 15.26% of the total relative plant cover. The third most dominant species was Sand Dropseed, which contributed 3.52% of the total plant cover or 13.29% of the total relative plant cover. Alkali Sacaton, was the fourth most dominant plant, contributing 3.14% of the total plant cover or 11.85% of the total relative plant cover. The locations of the 21 cover transects sampled on this site are shown on Map 20, Loadout Reference Area - 2013 Transect Map. The sample adequacy calculations in Table 2, 2013 Mine -Statistical Summary and Sample Adequacy Calculations, document that the number of transects required to characterize the "total plant cover" was 6.0 transects and 11.2 transects for "allowable plant cover" at the 90% confidence interval. When IME sampled this site in 2007, during what was one of the wettest years in decades, it was determined that total canopy cover averaged 39.00%. All warm season species contributed 30.86% of the total plant cover or 79.13% of the total relative cover. The two most dominant warm season species contributed 27.54% of the total cover or 70.62% of the total relative cover. When Keenan, Inc., sampled an undisturbed site very close to this reference area in 1980, total basal cover averaged 19.35%. All warm season species contributed 11.92% of the total basal cover and accounted for 61.60% of the total relative cover. The two dominant warm season species contributed 64.18% of the total relative cover. Forage Production. The results obtained from the sampling of the 30 forage production transects are found in Table 22, Loadout Reference Area — 2013 Production. Forage production averaged 8.37 g/1/4 m2 or 298.3 pounds per acre. Perennial grasses produced 7.41 g/1/4 m2 or 264.1 pounds per acre and accounted for 88.5% of the forage production. Perennial forbs produced 0.96 g/1/4 m2 or 34.2 pounds per acre and accounted for 11.5% of the forage production. The locations of the 30 forage production transects sampled on this site are shown on Map 20, Loadout Reference Area - 2013 Transect Location Map. The sample adequacy calculations in Table 2, 2013 - Statistical Summary and Sample Adequacy Calculations, document that the number of samples required to describe this site at the 90% confidence interval with respect to the parameter of forage production was 55.6 transects. When IME sampled this site in 2007, forage production averaged 41.36 g/1/4 m2 or 1,474.4 pounds per acre. Perennial grasses produced 35.34 g/1/4 m2 or 1,259.5 pounds per acre and accounted for 85.4% of the forage production. Perennial forbs produced 6.03 g/1/4 m2 or 214.9 pounds per acre and accounted for 14.6% of the forage production. Species Diversity. All warm season grass species contributed 16.52% of the total plant cover or 62.29% of the total relative cover. The two most dominant warm season plant species contributed 12.52% of the total plant cover or 47.21% of the total relative plant cover. The four most dominant plant species contributed 19.71% of the total plant cover or 74.32% of the total relative plant cover. 18