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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 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 comparison of the mean total species density of the reclaimed <br />area to the reference area - derived standard number (above). If the reclaimed area mean exceeds the <br />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 />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 proposed standard is 63% (0.9 x 70 %). (The assessment <br />of internal similarity was performed on data from the extended reference areas) <br />The Motyka similarity index is used as follows: <br />IS = 2c / (a + b) <br />Where <br />IS = Motyka Index of Similarity <br />c = the smaller of the paired species density values (for each lifeform) of <br />the reclaimed and reference areas* <br />a = total of species density values for lifeforms of the reclaimed areas <br />b = total of species density values for the lifeforms of the reference area* <br />* Weighted average lifeform species density using the Sage Creek Reference Areas (weighted based on <br />83% original extent of Mountain Brush and 17% original extent of Sagebrush). <br />8 <br />