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A diversity index is a method of measuring how many different types (e.g. species) there are in a dataset (e.g. a community).Diversity indices are statistical representations of different aspects of biodiversity (e.g. richness, evenness, and dominance), which are useful simplifications for comparing different communities or sites.
This is also the formula for the inverse Simpson index, or the true diversity of order 2. This definition is still the most commonly-used in political science . This measure is equivalent to the Herfindahl–Hirschman index , used in economics; the Simpson diversity index in ecology; the inverse participation ratio (IPR) in physics; and the ...
Species diversity [3] is the relationship between species evenness and species richness. There are many ways to measure biodiversity within a given ecosystem. However, the two most popular are Shannon-Weaver diversity index, [4] commonly referred to as Shannon diversity index, and the other is Simpsons diversity index. [5]
Morisita's overlap index, named after Masaaki Morisita, is a statistical measure of dispersion of individuals in a population. It is used to compare overlap among samples (Morisita 1959). This formula is based on the assumption that increasing the size of the samples will increase the diversity because it will include different habitats (i.e ...
A calculated value of Pielou's evenness ranges from 0 (no evenness) to 1 (complete evenness). When taken into account along with other indices such as Simpson's index or Shannon's index, a more thorough description of a community's structure can be interpreted. [4]
The Shannon index is the most commonly used way to quantitatively determine species diversity, H, as modeled by the following equation: = = The Shannon index factors in both species evenness and species richness, as represented by the variables p i and s, respectively. The lowest possible value of H is zero, and the higher a community’s H ...
These include Gini's index of mutability, [13] Simpson's measure of diversity, [14] Bachi's index of linguistic homogeneity, [15] Mueller and Schuessler's index of qualitative variation, [16] Gibbs and Martin's index of industry diversification, [17] Lieberson's index. [18] and Blau's index in sociology, psychology and management studies. [19]
Definitions of alpha diversity can also differ in what they assume species diversity to be. Often researchers use the values given by one or more diversity indices, such as species richness (which is simply a count of species), the Shannon index or the Simpson index (which take into account also species proportional abundances).