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• (Wadge Pasture), and E (1985,1986 Wolf Creek) all would meet the cover standard set by the <br /> Sagebrush Reference Area in 1989, and Area D (Wadge Pasture) would meet even the Mountain <br /> Brush Reference Area standard. It should be pointed out that the Wadge Pasture (Area D) had the <br /> highest cover levels of any reclaimed area despite (or perhaps because of) having been grazed <br /> each of the past three summers. <br /> Total vegetation cover in the reclaimed areas is presently comparable to the sagebrush and <br /> mountain brush vegetation of the region. However, the unusually high cover in the two reference <br /> areas selected to represent these native types at the Seneca II Mine may set a standard that is <br /> difficult to achieve in the reclaimed areas. Cover data usually have a small variance, resulting <br /> in small confidence limits, often only 1 to 3 percent. Thus, unless cover in a reclaimed area is <br /> within about 1 to 3 percent of the performance standard, no achievement of the standard can be <br /> shown. <br /> Average vegetation cover in the reclaimed areas was highest in 1987 (72.1 percent), slightly <br /> lower in 1988 (70.9 percent), and substantially lower in 1989 (48.4 percent). See 1989 <br /> • cover tables in Appendix 1 and the 1987 and 1988 Revegetation Monitoring Reports for the <br /> Seneca 11 Mine. The lower 1989 vegetation cover reflects a change of 24 percentage points from <br /> the vegetation cover measured in 1987. The change in cover from 1987 to 1989 for the <br /> Sagebrush Reference Area was nearly the same as the reclaimed areas at approximately 25 <br /> percentage points. On the other hand, the Mountain Brush Reference Area only dropped 9.7 <br /> percentage points from 1987 to 1989. The reclaimed areas are dominated by herbaceous species <br /> and the Sagebrush Reference Area also has a heavy herbaceous component. It is speculated that <br /> the herbaceous species are more greatly affected by dry conditions than are shrubs, especially <br /> the tall shrubs that dominate cover in the mountain brush community, perhaps because these <br /> woody species generally root more deeply and may have greater carbohydrate reserves. In <br /> addition, the atypically mesic conditions of the Mountain Brush Reference Area may further <br /> buffer cover values in this area from the effects of drought. This may lead to a lack of <br /> proportional response to climatic conditions, thus compromising one of the basic assumptions <br /> regarding reference areas. <br /> Reasons for the atypically lush vegetation cover in the Mountain Brush Reference Area include <br /> • east-facing slope, protection from wind and late-afternoon sun by a cliff immediately to the <br /> 17 <br />