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A technical standard for production is appropriate because of a lack of an adequate <br /> • reference area representing the postmining land use of dryland pasture or rangeland where <br /> herbaceous species will dominate. The above technical standard reflects the potential <br /> productivity of the soils replaced in the reclaimed areas and the climatic conditions of <br /> the general area. <br /> Species Diversity. Species diversity will generally be evaluated by comparing the <br /> relative importance of species occurring in the upland sagebrush reference area to the <br /> relative importance of species occurring in the reclaimed areas. The relative importance <br /> value to be used is relative cover with the minimum value set at 3 percent relative cover. <br /> Because the postmine land use is a combination of dryland pasture and rangeland, a <br /> modified comparison between the two areas will be made. <br /> The upland sagebrush reference area contained three grasses, two shrubs, one succulent, <br /> and one annual grass with relative cover values greater than 3 percent. The forb <br /> component was generally lacking in individuals and none achieved values of 3 percent <br /> relative cover. The combined species, (i.e., those with relative cover greater than 3 <br /> percent) totaled nearly 85 percent of the relative cover. Establishment of succulents and <br /> • annual grasses in the reclaimed communities is either impractical or undesirable. Thus, <br /> these two growth forms will not be considered. Again, because of the combined postmine <br /> Land use of dryland pasture and rangeland, the establishment of shrubs in the reclaimed <br /> community will not be at or near premine levels. The shrub fourwing saltbush is included <br /> in the primary seed mix to enhance overall woody densities and has been successfully <br /> established in the past. No forbs were found to have relative cover values equal to or <br /> greater than 3 percent. The primary seed mix includes two forbs (one is also a legume), <br /> one subshrub, and one shrub. <br /> Eight grasses are included in the mix. This mix has been developed to achieve the <br /> postmine land use and be equal to or superior in utility to the premining vegetation. <br /> The species diversity standard to be achieved will be three grasses, one forb, and one <br /> shrub. The three grasses, one forb, and one shrub will have relative cover values of 3 <br /> percent or greater. The establishment of at least one forb will mitigate for a reduction <br /> in seasonal variety and shrub composition. The combined relative importance will not be <br /> greater than 85 percent and no one species will contribute greater than 40 percent <br /> • relative importance. <br /> 22-13 Revised 07/25/91 <br />