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<br />-13-- <br />Revised OCT 3 0 19 tit <br />1961; Lloyd aid Ghelardi, 1969 and Pielou, 1966). As a diversity index <br />for canmulity analysis, the function describes the average degree of <br />uncertainty of predicting the species of a given iid.ividual picked at <br />ra{dan from the ootmauiity. This uncertainty and the index increase both <br />as the number of species increases aid as the individuals are distributed , <br />mire and 1ror'e equitably aarstg species alr~dy present. The general fornaila <br />foi this index is as follaas: <br />B - L pi loge pi <br />• <br />where Pi = decimal fraction of total individuals belonging to the ith <br />species (an this case, perceit basal cover is used to express p.). <br />i <br />This index any vary fran a value of D for habitats containing a single <br />species (e.g., an alfalfa field) to values of 4 or S for oser¢a~ities <br />containing many species, each with a mall nurtiber of individuals. The <br />application of this fortmnla to basal over data to provide estimates of <br />species diversity is illustrated by tl~ folloding example: <br />$ Basal <br />Life Form Species ~~' - - PilOgepi <br />GYass Sporobolus cryptandrus 3.9 ~ 0.36 <br />Forb La a texana 1.5 0.31 <br />Salsola kali 0.6 0.19 <br />Sisymffiivm altissimm~n 0.6 0.19 <br />Sphaeralcea coccinea 1.1 0.26 <br />Sub-shrub crnttierrezia sarothrae 0.8 ~ 0.22 <br />'TOTAL 8.5 1.52 <br />Shamon~7einer Irdex = 1.52 <br />• <br />(Revised March 2006) Attachment 2.05.6(2)-1-18 <br />