2010-03-12_REPORT - C1981019 (8)

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2.3 Section 16 2.3.1 S16 Year 10 S16Y10 is comprised of 2 units in Section 16 (S16016 and S16017) that make up 25.4 acres of gently sloping revegetation that has a predominately o southeasterly aspect. This unit was seeded in 1999 o and therefore, has undergone ten growing seasons prior to sampling in 2009. A total of 31 plant taxa were observed in the unit (see Table AB-1). Current annual production across the unit averaged 1,516 pounds per acre in 2009 with perennial grasses and - r' perennial forbs the dominant categories (see Compendium 6). Ground cover in S16Y10 consisted ® of 72.5% live vegetation, 0.3% rock, 20.6% litter, and bare soil exposure of 6.7% (see Table AB-2 and f Chart AB-1). Perennial cover across the unit averaged 70.3% with annual and biennial cover averaging 2.3%. Dominant taxa were Kentucky bluegrass, basin wildrye, crested wheatgrass (Agropyron cristatum), streambank wheatgrass, and _ thickspike wheatgrass, with 17.9%, 15.2%, 7.2%, 7.1%, and 5.1% average cover, respectively. Woody plant density was determined from 20 belt transects. Density (Table 3) totaled 105 young and mature Q10Mft-Revcaetatim MOni[aren SwUon 16 - 10 Year OW Revegetadon 41, stems per acre with big sagebrush (Artemisia .? tridentata) the dominant woody plant. With regard to diversity, S16Y10 exhibited eight perennial grasses with between 3% and 50% relative cover and relative forb cover of 3.3% (excluding noxious weeds) This unit easily passes both the cover and production bond release comparisons to the reference areas (see Charts 1 and 2). Unit S16Y10 currently passes the bond release diversity standard of two perennial grasses with between 3% and 50% relative cover and relative forb cover with between 1% and 50% (see Charts 3 & 4). This unit contains 13.06 acres of qualified shrub units which contribute to the woody plant density standard of 150 stems per acre on 3% of the reclaimed land. Shrub patches were delineated using 300 stems per acre as a guideline. Therefore, actual acreage that meets the new standard is presumably higher. Noxious weeds are well controlled in this unit. Annual bromes are not present in patches, therefore, annual cover is quite low. At present, S16Y10 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. CEDAR CREEK ASSOCIATES, Inc. Page 22 Colowyo Mine 2009 Revegetation Monitoring Report • • • • r r r,