2020-03-24_PERMIT FILE - C1981019A (39)

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RULE 2 PERMITS ecological stability. The seed mixture contains a variety of grasses, forbs and shrub species well adapted to the soil and moisture conditions found at Colowyo. The diverse seed mixture is capable of self-selection for each reclaimed micro-habitat encountered in the reclaimed areas. The diverse seed mixture is required to ensure quick erosion control for the first few years of reclamation as well as obtaining the desired post-mining vegetative community with the same seasonal variety and lifeform of the pre-mined area. The species and seeding rates indicated on this"grassland"mix resulted from in-depth analyses of past mixes and the resulting emergence and dominance within revegetated areas. A total of eleven different measurement events on Colowyo reclamation coupled with a performance evaluation for each taxon in the 2002 mix resulted in development of the mix indicated on Table 2.05-7 as well as Table 2.05-9. Examples of changes resulting from this analysis include: elimination of streambank wheatgrass(less palatable and redundant with thickspike),elimination of big bluegrass from the grassland mix for lack of performance, elimination of Sainfoin from both mixes for lack of performance, and substantial increases in the amount of sagebrush seed in both grassland and especially sagebrush steppe targeted mixes. These changes, including the planted amounts, have resulted in an increase in the number of seeds per square foot, from 29.2 / ft2 to 75.1 / ft2. Much of the increase is due to the substantial increase of sagebrush seed from 0.02 pounds PLS/acre to 0.5 pounds PLS/acre. Although inclusion of sagebrush seed is contrary to the intended vegetation community that targets the grazingland land use, this change has been adopted to increase the potential for development of shrub patches within the grassland community as well as to add structural diversity to the community and overall reclaimed area. If too much sage results from this mix for the intended land use, the amount of sagebrush seed can be reduced. If excess shrub numbers result from early revegetation efforts,then managerial techniques are readily available to reduce sage populations once the land surface has been transferred back to the landowner if Colowyo does not choose to reclassify the area as sagebrush steppe and apply for bond release under those criteria. Table 2.05-8, List of Contingency Substitutions for Table 2.05-7 and Table 2.05-9, provides the approved list of contingency substitutions for the seed mixes should certain taxa be unavailable or unwarranted in any given year. The reclamation seed mixture for areas targeting sagebrush steppe(wildlife habitat land use—sage grouse brood rearing habitat), as shown in Table 2.05-9, Reclamation Seed Mixture, also contains sufficient diversity for ecological stability. This mixture contains a variety of grasses, forbs and shrub species well adapted to the soil and moisture conditions found at Colowyo and should provide both the structural diversity and life form diversity necessary for habitat requisites of young sage grouse. The seed mixture is capable of self-selection for each reclaimed micro-habitat encountered in the reclaimed areas and contains sufficient sagebrush seed to hopefully encourage at least some emergence each year and substantial emergence occasionally. There is potential, that too much sagebrush seed (115 seeds / ft2) has been incorporated into this mix, and given recent experience with new planting techniques designed for use at Colowyo in and after 2008, the amount of seed may need to be adjusted at some future point*. However, * By example, as of 2007 the CSU shrub test plots exhibited an average sagebrush population of 3,500 plants per acre. This population resulted from an initial 0.25 pounds PLS of seed in the mix,following an excellent recruitment year. Rule 2 Permits 2.05-28 Revision Date: 12/20/19 Revision No.: TR-135