Shannon index

Species richness, abundance, and Shannon index.

When x is in units of population/species, is a measure of biodiversity and is called the Shannon index.

Often researchers use the values given by one or more diversity indices, such as species richness, the Shannon index or the Simpson index.

The Shannon index equals log(D), and in practice quantifies the uncertainty in the species identity of an individual that is taken at random from the dataset.

When all types in the dataset of interest are equally common, all values equal 1/R, and the Shannon index hence takes the value ln(R).

Soil scientists have pragmatically adapted the concept of biodiversity and used diversity index such as Shannon index using taxa from well-accepted international soil classification systems.

Such indices include species richness, the Shannon index, the Simpson index and the complement of the Simpson index (also known as the Gini-Simpson index).

The Shannon index has been a popular diversity index in the ecological literature, where it is also known as Shannon's diversity index, the Shannon-Wiener index, the Shannon-Weaver index and the Shannon entropy.