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For purpose of establishing the range of species density within the reference areas, the 75% range of <br />variation is established as: <br />zxs <br />Where: <br />z = the number of standard deviations (both ways from the mean) <br />encompassing 75% of the normal distribution (= 1.15; see Rohlf and <br />Sokal 1969, 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 in the <br />reference areas. Mathematically this is: <br />Mean reference area species density (no. of species per 100 sq.m.) - 1.15 s <br />(Here the mean is the un- weighted mean of the five reference areas and the standard deviation is <br />derived from those five means) <br />The standard is based on a weighted average as done with cover and production. <br />Note that this test addresses total species density, not just native species density (see Test D) below). <br />Noxious weeds are omitted. The point of addressing total species density, including annual /biennial <br />species and introduced species, is that the total species density is arguably a strong indication of the <br />existence of niche spaces that could eventually be occupied by the native forb and woody plant species <br />typical of the pre- mining plant communities. <br />The final step for the Test B assessment is a straight comparison of the mean total species density of the <br />reclaimed area to the reference area - derived standard number (above). If the reclaimed area mean <br />exceeds the standard, the Test B is passed. <br />Alternative Test C): Species Density Distribution Assessment Among Lifeforms <br />This test relates to the distribution of species presence among the various lifeforms in comparison to the <br />reference areas. This standard uses the Motyka similarity index to assess the resemblance of species <br />density distribution by lifeform of the reclamation vegetation to that of the reference areas. Because the <br />9 <br />