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4.4.1.4 Species Diversity Standard <br /> As discussed in Section 3.6.1.3 species diversity is commonly defined as the number of species which <br /> occur in a community (richness) in combination with the physical distribution of individuals among those <br /> species (evenness). This is about as far as ecologists have progressed in the establishment of an <br /> accepted diversity concept. A review of available literature provides one with a host of techniques and <br /> formulas all claimed to be the method for calculating diversity (refer to Section 3.6.1.3). This point is <br /> also confirmed by Hill (1973)who stated: <br /> "Unfortunately, when we look for a suitable numerical definition, we <br /> find that no particular formula has a pre-eminent advantage, and that <br /> different authors have plausibly proposed different indicies." <br /> The problems associated with diversity indicies do not stop here. Hill continues in the same publication <br /> by saying "...whereas it is easy enough to define measures of diversity which apply to a particular <br /> sample, very often they will have no meaning when applied to in the whole community." According to <br /> Hill (1973), the reason for this is that as the size of the sample (n) is increased, the calculated diversity of <br /> the community will likewise increase. As sampling intensities fluctuate yearly due to differences in <br /> population variances, so will the diversity index. <br /> Just as other authors on diversity, Hill (1973) presents his own technique for defining the elusive parame- <br /> ter. Hill proposes that one should attempt to estimate the "effective number of species" in a sample. <br /> According to the Office of Surface Mining, the ideal formula for defining diversity is yet another formula <br /> that is a modification of the Shannon and Weiner(Weaver) formula (Bonham, et.al., 1980). This formula <br /> is described as follows: <br /> H' _- E pi log pi <br /> where: H' = diversity measure <br /> pi = Ni/N <br /> Ni = dominance measure for ith species <br /> N = Sum of all species dominance measures <br /> The Office of Surface Mining (OSM) states that the Shannon-Weiner(Weaver) formula is recommended <br /> by Pielou (1975) as the appropriate index for diversity (Bonham, et.al, 1980). However, based on past <br /> publications by Pielou (1966, 1966b), he concluded the Shannon and Weaver formula for diversity is <br /> inappropriate. According to Pielou (1966), H' should only be used to calculate diversity under the <br /> following assumptions: <br /> 4-120 <br /> Revision: =1 <br /> Approved: Z�.s/s� <br />