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2.4.3 WP011 <br />WP011 is comprised of 1.7 acres of steeply <br />sloping revegetation that has a predominately <br />northwesterly aspect. This unit was seeded in 2001 <br />and therefore, has undergone seven growing <br />seasons prior to sampling in 2008. A total of 32 ' <br />plant taxa were observed in the unit (see Table AB- O <br />1). Current annual production across the unit / <br />averaged 2,638.0 pounds per acre in 2008 with <br /> <br />perennial grasses the dominant category (see 0 <br />Compendium 7). Ground cover in WP011 consisted <br />of 71.2% live vegetation, 0.3% rock, 26.5% litter, <br />and bare soil exposure of 2.1%. Perennial cover <br />across the unit averaged 66.9% with annual and <br />biennial cover averaging 4.3%. Dominant taxa were <br />cicer milkvetch, thickspike wheatgrass, smooth `"°°•'"ime <br />brome (Bromus inermis), streambank wheatgrass <br />and Siberian wheatgrass, with 19.3%, 12.6%, 7.2%, <br />5.3%, and 5.1% average cover, respectively. <br />Woody plant density was determined from 20 belt -.® . <br />transects. Density (Table 2) totaled 66.8 young and <br />mature stems per acre with mountain snowberry <br />:,•?-x.,.??., <br />(Symphoricarpos oreophilus) the dominant woody WP0°'"'"`` <br />plant. With regard to diversity, WP011 exhibited 8 <br />perennial grasses and 1 perennial forb with between 3% and 50% relative cover <br />O <br />O O O <br />A O O <br />Unit WP011 currently passes the bond release diversity standard of 3 perennial grasses and 1 <br />perennial forb with between 3% and 50% relative cover. In addition, this unit passes bond release <br />comparisons to the reference areas for both cover and production (see Charts 3 and 5). This unit does <br />not presently meet the woody plant density standard of 90% of 1000 stems per acre and will probably <br />not meet this in the foreseeable future due to the heavy competitive grass cover. See Appendix AA - <br />Section 7.3 for a discussion on options and recommendations with regard to woody plant density. <br />Noxious weeds appear to be well controlled in this unit, however there were observations of Canada <br />thistle. Annual bromes currently represent 3.9% cover in relatively distinct patches. According to annual <br />monitoring presented on Compendium 7 these patches are continuing to shrink. Therefore, they present <br />little problem for this unit. <br />At present, WP011 is a good example of an improved pasture grassland community that would <br />contribute to the local system as foraging habitat for wildlife (especially elk), as well as provide a variety <br />of management opportunities for livestock grazing. <br />Rio Tinto Energy America/Colowyo Mine Page 24 Revegetation Monitoring - 2008