proposed that -diversity for a groupof samples from a given area can be measured as the average dis-tance or dissimilarity from each sample to the group centroid, usingan appropriate dissimilarity measure. So far, the classic Jaccard(1900) and Sørensen (1948) dissimilarity measures are the mostwidely-used ecological parameters for summarizing compositionalvariability. Otherwise,the Bray–Curtis (1957) dissimilarity measure with relative abun-dance information has also been used to summarize -diversity(Ellingsen and Gray, 2002; Magurran, 2004; Olszewski, 2004).Furthermore, to definite what is meant by the “variability in com-munity structure”, an appropriate dissimilarity measure was usedfor allowing the relative weight placed on changes in composition versus abundance to be specified explicitly