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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) encompassing 75% of the <br />normal distribution (= 1.15; see Rohlf and 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 />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 Iifeforms 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 />average internal resemblance (i.e. between- sample similarity) of applicable reference areas for species <br />density data is often in the range of 70 %, the standard is 63% (0.9 x 70 %). (The assessment of internal <br />similarity was performed on data from the extended reference areas) <br />10 <br />