2009-03-27_REPORT - C1981019 (7)

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2.2 East Pit 2.2.1 EP038 EP038 is comprised of 4.1 acres of gently sloping revegetation that has predominately an easterly aspect. This unit was seeded in 2001 and therefore, has undergone seven growing seasons prior to sampling in 2008. A total of 26 plant taxa were observed in the unit (see Table AB-1). Current annual production across the unit averaged 1,275.5 pounds per acre in 2008 with perennial grasses and perennial forbs the dominant categories (see Compendium 1). Ground cover in EP038 consisted of 69.9% live vegetation, 0.4% rock, 21.4% litter, and bare soil exposure of 8.5%. Perennial cover across the unit averaged 51.1% with annual and biennial cover averaging 18.8%. Dominant taxa were cheatgrass (Bromus tectorum), alfalfa (Medicago sativa), cicer milkvetch (Astragalus cice?, thickspike wheatgrass (Agropyron dasystachyum), and western wheatgrass (Agropyron smithii), with 13.3%, 13.2%, 10.5%, 7.5%, and 6.3% average cover, respectively. Woody plant density was determined from 20 belt transects (Table 2) and totaled 4 young and mature stems per acre with four-wing saltbush (Atriplex canescens) the dominant woody plant. With regard to diversity, EP038 exhibited 5 perennial grasses and 2 perennial forbs with between 3% and 50% relative cover. 0 0 0 0 0f ,0 0 0 0 m m m m ?® m 0 Unit EP038 currently passes the bond release diversity standard of 3 perennial grasses and 1 perennial forb with between 3% and 50% relative cover (see Chart 6). This unit easily passes both the cover and production bond release comparisons to the reference areas (see Charts 3 and 4). This unit does not presently meet the woody plant density standard of 90% of 1000 stems per acre and will probably not meet this in the foreseeable future due to the heavy competitive grass cover. See Appendix AA - Section 7.3 for a discussion on options and recommendations with regard to woody plant density. Noxious weeds were not observed in this unit. There are several small patches of annual bromes scattered throughout the unit. Although these bromes currently represent 18.3% cover, according to monitoring presented on Compendium 1 the populations are shrinking with increased competition from perennial grasses. At present, EP038 is a good example of an improved pasture grassland community that would contribute to the local system with respect to both cover and foraging habitat for wildlife (especially elk), as well as provide a variety of management opportunities for livestock grazing. Rio Tinto Energy America/Colowyo Mine Page 12 Revegetation Monitoring - 2008