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Vegetation Type % of <br />Affected Area' <br />Aspen Woodland ~ 21 <br />Mountain Brush ~ 28 <br />Steep Mountain Brush 10 <br />Sagebrush/Snowberry 14 <br />WW/Alkali Sagebrush 27 <br />TOTAL WEIGHTED HERBACEOUS COVER <br />Total "All-hit" Weighted <br />Herbaceous Cover 'Contribution <br />90.1 1 8.9 <br />67.1 1 8.8 <br />44.1 4.4 <br />52.8 7.4 <br />61.4 16.6 <br /> 66.1 <br />The performance standard for cover in the sampling year 1997 would thus have been 59.4 <br />percent (66.1 x 0.91. The reclaimed area number to be compared to this would be the "all-hit" <br />total herbaceous cover number. Note that for purposes of assessing the efficacy of~ground <br />cover for erosion control, a different number-the total ground cover based on the sum of <br />"first-hit" vegetation plus litter plus rock plus standing dead-would be appropriate. <br />. The nature of plant communities dominated by large woody plants is in fact that there •is <br />• ample opppourtunity to encounter wring vertical projection from~above,.more than.one and <br />. ~ even several species before ac~o a ground. In consideration of the difference. in the <br />degree towhich stratification allows for the accumulation of multiple "hits" during point <br />projections during sampling, a correctionis needed to adjust for the differing structure ~ of <br />reclaimed and reference communities. Thus, for a given set of ERA data, a' weighted average <br />. of total hits per sample will be calculated as above and compared to the average total hits per <br />sample for the reclaimed area being tested. The weighted "all-hit"herbaceous cover from the <br />ERA's will be adjusted by that ratio. <br />Average vegetation cover las opposed to only herbaceous cbverl is to be used for the <br />revegetation areas because monitoring data at the Seneca II Mine shows that vegetation cover <br />in reclaimed areas is, for all practical purposes, comprised of herbaceous species. ~ This is true <br />' even in reclaimed areas with the highest shrub densities. The above method allows for the <br />effects of climatic variability to enter into comparisons. .An example of a projected cover <br />comparison value is presented here. Using the vegetation cover data collected in 1990 <br />baseline studies at Seneca II-W, a weighted herbaceous cover value was estimated. This value <br />multiplied by two resulted in an example cover comparison value of approximately 55 percent. <br />• ~ This example illustrates that when the standard is met, a sufficient level of cover will be <br />present to control erosion andstabilize the surface, particularly when one considers that little <br />40a ~ ~ Revised 1 /99 <br />