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2011 Assessment of BRB PSCM -1 for Compliance with Phase Ill Performance Standards <br />COVER - PERFORMANCE STANDARD BASED ON REFERENCE AREA MEANS <br />Calculation of 90 percent of the cover performance standard appropriate for 2011 sampling based on <br />reference area means is demonstrated below. <br />Mountain Brush Reference Area Allowable First -Hit Herbaceous Cover *(21.0 %) X 2 = 41.9% <br />Sagebrush Reference Area Allowable First -Hit Herbaceous Cover *(44.4 %) X 2 = 88.8% <br />90 percent of the Cover Standard = 0.90 [0.83(41.9 %) + 0.17(88.8 %)] = 44.9% <br />* Herbaceous cover adjusted by subtracting noxious weeds and annual/biennial plant cover in excess of 10% of the remainder. <br />The mean allowable first -hit herbaceous vegetation cover sampled in 2011 BRB PSCM -1 was 55.8 <br />percent, exceeding 44.9 percent, which is 90 percent of the cover performance standard (Figure C -1, <br />Table C -1). ). The 2011 BRB PSCM -1 allowable first -hit herbaceous cover is the result of subtracting <br />first -hit non - herbaceous cover (shrubs) on an individual transect basis and subtracting the mean first -hit <br />noxious weed cover from the observed mean first -hit total vegetation cover. The average annual and <br />biennial sampled cover of 2011 BRB PSCM -1 was not greater than 10 percent of first -hit relative cover <br />and therefore no "excess" annual /biennial cover deduction was used in 2011. <br />COVER — PERFORMANCE STANDARD WITH UPWARDLY ADJUSTED MOUNTAIN BRUSH REFERENCE <br />COMPONENT <br />Sample adequacy for total vegetation cover was achieved for the reference areas and BRB -5. For total <br />allowable herbaceous cover, adequacy based on first -hit values was achieved for BRB -5 and the <br />Sagebrush Reference Area, but it was not for the Mountain Brush Reference Area. <br />In consideration of the lack of a sample size sufficient to detect a 10 percent reduction in the mean with <br />90 percent confidence (i.e. sample adequacy), the upper limit of the possible values of the true mean <br />(with a sample size of 21) was determined. This can be done in either of two ways. <br />1) Confidence Intervals <br />s 9.15 <br />C. I. = — *t = *1.725 =3.44 <br />2i <br />20.95 + 3.44 = 24.39 <br />24 <br />