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Seneca Il Mine <br />SL-5 Phase 11 Bond Release Request <br />Species Composition and Diversity <br />June 2011 <br />The species composition and diversity evaluation below is based on the species diversity <br />revegetation success evaluations presented in Exhibit 2.05.4-E1 of the approved PSCM permit. <br />The seasonality of northwestern Colorado native range surrounding the Seneca II Mine permit <br />area is cool season and the established reclamation is also cool season. <br />Test A requires that no single plant species may exceed 60% relative cover. A determination of <br />PASS was made because the species with the greatest relative cover (Thinopyrum intermedium) had <br />21.29 percent relative cover which is far less than the 60 percent limit. <br />Test B requires the total mean species density in the reclaimed area equals or exceeds the central <br />75% of the distribution of the area weighted overall species density determined from the cover <br />sampling in the 100 sq.m. sample plots of the reference area. Species density numbers were <br />subjected to sample adequacy assessment. For purpose of setting the range of species density <br />within the Reference Area, the 75% range of variation would be established as: <br />zxs <br />Where: <br />z = the number of standard deviations (both ways from the mean) encompassing 75% of <br />the <br />normal distribution (= 1.15; see Rohlf and Sokal 1969, Table P) <br />s = area weighted species density standard deviation for the reference area (n-1) <br />The standard is the point at which the central 75% of the distribution of overall species density in <br />the reference areas begins (the midpoint (probability distribution) of the lower half of the range <br />of variation for the reference area). Mathematically this is: <br />Weighted mean reference area species density (no. of species per 100 sq.m.) - 1.15 s. <br />The results of Test B are: <br />Weighted reference area species density = 25.31 <br />Phase II bond release block species density = 19.9 +/- 1.14 <br />11