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Peabody Sage Creek Mine July 2014 <br />SL -3 Phase III Bond Release Request <br />Alternative Test B): Total Species Density Test <br />In this test, overall reclamation diversity is judged based on the species density values associated <br />with cover sampling in 100 sq.m. sample plots. Species density sample adequacy is assessed along <br />with cover sample adequacy. <br />In order to establish the range of species density within the reference areas and develop the <br />standard, the 75% range of variation is established as: <br />zxs <br />Where: z = the number of standard deviations (both ways from the mean) <br />encompassing 75% of the normal distribution (= 1.15; see Rohlf and Sokal 1969, <br />Table P) <br />s = standard deviation (n -1) <br />The standard is the lower bound of the central 75% of the distribution of overall species density <br />in the reference areas. Mathematically this is: <br />Mean reference area species density (no. of species per 100 sq.m.) - 1.15 s <br />The standard is based on a weighted average as done with cover and production. <br />Note that this test addresses total species density. Noxious weeds are omitted. The reason to <br />address total species density, including annual /biennial and introduced species, is that total <br />species density is arguably a strong indication of the existence of niche spaces that could <br />eventually be occupied by the native forb and woody plant species typical of the pre - mining plant <br />communities. <br />The final step for the Test B assessment is comparison of the mean total species density of the <br />reclaimed area to the reference area - derived standard using the classic t -test below. If the <br />reclaimed area mean exceeds the standard, Test B is passed. <br />Probability adjusted density standard — � <br />tcra %c = <br />(k) <br />18 <br />