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North Thompson Creek Mine: -Justification for changing the species diversity success standard Present standard: The present standard, as stated on p. 4-64 of the permit document is as follows: "Species diversity in the Mountain Shrubland Dry Phase will be considered acceptable if sampling demonstrates that three species of cool season grasses, two species of (orbs and three species of shrubs and/or trees have been established. In addition, no one species shall comprise less than 3% of the total cover or more than 40% of the total cover. This standard will be acceptable for all areas (i.e., refuse pile, truck dump, etc.)." Thus a total of 8 species are required to be found on site having a relative importance (cover) of between 3 and 40%. Technical Revision 14 -Relevant History 7'he present species diversity standard was developed for the entire mine site at a time when three communities were considered to exist on the site. Each of these communities had its own applicable standards with the exception that the species diversity standard was comprehensive to the enure site. Prior to the submittal of TR-14, it was determined that the requirement of separate success standards for two of the three communities was unreasonable in light of how small they were. The two communities in question were represented on site by 0.6 and 1.3 acres. Because both communities represented less than 10 acres and less than 5% of the disturbed area, both were considered to be minor communities in congruence with page 3 of the Division's Vegetation Guidelines ( ui lines for Compliance with Land Use and Vegetation Requiremenu of approved the removal of specific cover, production, and woody plant density standards applying to these communities. What was overlooked, however, was that the species diversity standard was designed to take into account these two minor communities as major ones. Thus, consistent with the changes made in 1992, the species diversity should be changed as well to reflect that only one major community exists on the mine site and that only one reference area applies toward the determination of success. Formulating a new species diversity standard: The actual process of arriving at a suitable diversity standard is outlined on pages 13 and 14 of the Division's Vegetation Guidelines. Using the recommended method, the standard should be based on the pre-mine or affected community cover data. As per p. 7 of the Guidelines, "Species composition is based on all hits on vegetation" rather than on first-hit data. Thus, the relative cover that should be used to draw up a diversity standard is that based on multiple hit data. Chart 3.2.2-1 on page 27 of the baseline survey contains the cover data collected for the affected Mountain Shrubland Dry Phase community. The cover summarized at right in the chart is the absolute cover based only on one-hit data. The chart does include (in parentheses) multiple hits beyond the first hit. However, the baseline survey does not include any calculated relative cover percentages. Enclosed as Table 1 are the relative cover percentages based on the multiple hit data listed in the baseline report. As Chart 1 shows, species in 1980 that had a relative cover greater than 3% in the affected area included Amelanchier a[nifolia, Cercocarpus montanus, Purshia tridentata, Quercus