An Index of Diversity and the Relation of Certain Concepts to Diversity

The uses in ecology of the terms richness, diversity, homogeneity, and similarity are considered in the context of recent studies of plant and animal communities. Various uses of divesity are reviewed and an index of diversity derived from the distance measure of similarity is suggested. This index is Σ i = 1 n 2 i where S equals the number of species and n equals the number of individuals in each species. This index is compared with other indices of diversity. The principal problem of measuring diversity is the assessment of the homogeneity or similarity of the sample or samples being studied. An advantage of the proposed index is that it derives from a measure of similarity of which it is a special case, and it is a special case, and it is a more natural and familiar representation of points in a coordinate system.