2020-07-09_REVISION - C1981028 (12)

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Coors Energy Company: Keenesburg Mine Technical Revision 47 Modification of Reclamation Success Standards Sandsage and needlegrass contribute an average of over 70%the relative cover in the last 5 years (2000-2004) of monitoring with the other three native species contributing another 15% and cheatgrass contributing 5% (Table 1). Table 1: Osgood Sand Reference Area Data 2000-2004 (Savage and Savage 2005 Average Relative Cover(%) Scientific Name Common Name 2000 2001 2002 2003 2004 Average Grass:Annual Introduced Bromus tectorum cheatgrass 2.1 9.5 1.5 4.8 7.7 5.1 Grass: Perennial Desirable(Cool) Nassella viridula green needlegrass 25.1 12.1 12.0 25.5 26.9 20.3 Other Cool Season Perennial Grass 0.0 1.2 3.8 0.9 1.9 1.5 Grass: Perennial Desirable(Warm), Andropogon hallii sand bluestem 10.2 3.5 5.3 2.3 0.0 4.2 Bouteloua gracilis blue grama 8.1 4.3 15.8 1.1 1.9 6.2 Calamovilfa longifolia prairie sandreed 5.1 6.3 7.5 2.8 1.2 4.6 Forbs Various species 0.4 8.9 8.3 13.0 5.9 7.3 Shrubs/Succulents:Perennial Native Artemisia fillifolia 48.9 53.7 45.1 49.6 53.9 50.2 Other Shrubs/Succulents 0.0 0.6 0.8 0.0 0.6 0.4 Total Vegetation Cover' 104:0 104.0,1 104.0 104.0 104.0,1 1E14.0 A majority (84%) of the reclamation areas are mapped by the Natural Resources Conservative Service (NRCS)within the Deep Sand Ecological Site Description (ESD) with another 13% in the Rolling Sands ESD (USDA, NRCS 2020). The reference plant community for both these ESDs is dominated by sand bluestem,prairie sandreed, and switchgrass (Panicum virgatum), with the Rolling Sands ESD also including little bluestem (Schizachyrium scoparium) and Indiangrass (Sorghastrum nutans) as dominants, all being native perennial warm season species (Sprock et al. 2004 and Tecklenburg 2016). The ESDs state that under continuous grazing without time for recovery, the community is expected to move toward shrubs, short grasses, and unpalatable species. If this occurs over a long period, the community will transition to the shrub state dominated by sand sage, annual weedy forbs, and short grasses. This description suggests that the OSRA community composition was indicative of a native pasture that was in transition from the at-risk reference state to the shrub state but was not in the reference state. It was over 50% sand sage with less than 10% of the cover provided by the dominant reference species. While using data from this site as a model for creating the cover and production standards was arguably acceptable, using these data as a model for the diversity standard was inappropriate. The dominance of sand sage and green needlegrass was likely because these species are less palatable to livestock than most of the other species (USDA, NRCS 2019). Thus, if the reclamation goal is to establish a community with a diversity of viable forage opportunities, the OSRA did not meet that goal. 2 July 2020