2011-03-24_REPORT - C1981019 (10)

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2.2.4 EPO41 1 is comprise o 30.8 acres of t _ / moderately sloping revegetation. This unit was `,= f seeded in 2003 making 2010 the seventh growing v season. A total of 38 plant taxa were observed in the unit, 26 of which were perennial species (Table AB-1). Current annual production across the unit , averaged 1,793.3 pounds per acre in 2010 with / perennial grasses and annual forbs the dominant categories (Table 1 and Chart 2). Ground cover in + +g EP041 consisted of 47.2% live vegetation, 0.6% rock, 38.8% litter, and bare soil exposure of 13.5%. +r" Perennial cover across the unit averaged 36.4% r"'?s fa /7 with annual and biennial cover averaging 10.8%. + + ' Dominant taxa were streambank wheatgrass, ,Y cheatgrass, and basin wildrye with 15.0%, 4.3%, and 2.9% average cover, respectively. Sub- dominant taxa include Kentucky bluegrass (Poa `.. pratensis), thickspike wheatgrass, and western My4..Mini _R?Wk9!! MnNL4Ci!? `yryj ? 4Tki xuNS;50 ref. ?.?,r?,-?, wheatgrass (Agropyron smithii) with 2.8%, 2.6%, EP041 ° and 2.4% average cover, respectively. Woody plant density was determined from 20 belt transects. Density (Table 3) totaled zero young and mature stems per acre. With regard to diversity, EP041 exhibited six perennial grasses with between 3% and 50% relative cover and relative forb cover of 19.9% (excluding noxious weeds). This unit readily passes the production bond release comparison to the reference areas, but fails the cover comparison (Charts 1 and 2). Unit EP041 currently passes the diversity standard set forth by TR- 72 (Charts 3 and 4). Qualified shrub acres need to be delineated, but given that there were zero shrubs per acre identified in the woody plant density transects, expectations are that this unit will need to be grouped with adjacent units to meet the woody plant density standard of 150 stems per acre on 3% of the reclaimed land. Shrub patch delineations are slated for spring 2011. Noxious weeds appear to be controlled in this unit, but some musk thistle was observed. Annual bromes are present with 4.7% cover, down from 26.5% in 2007. Unit EP041 exhibits good production and diversity for seven-year old revegetation. However, the cover values exhibited by this unit should be considered below average. Perennial cover has decreased since 2007, but the relative cover by perennials has improved from 61.6% to 77.2%. Indications are that this unit is still on an appropriate trajectory for bond release, but more time is need. If future monitoring reveals expansion of annual or noxious species, chemical control may recommended. Overall, Unit EP041 should be monitored again in 2013, but solutions for meeting the shrub standard need to be discussed. Cedar Creek Associates, Inc. 18 Colowyo Mine 2010 Revegetation Monitoring Report