Diversity index

Coefficient reflecting the degree of diversity of a community. The expression of the diversity index is based on two parameters: the number of species and number of individuals per species. There are many indexes but the most commonly used is that of Shannon and Weaver (1949). It expresses the relative importance of the number of abundant species in a given environment. Thus, the greater the proportion of rare species and that of abundant species smaller, the greater the diversity index is. The index is minimal when all individuals belong to the same species and is maximal when each individual represents a distinct species.