Measuring Species Diversity Environmental scientists are often interested in evaluating both species richness and species
evenness, so they have come up with indices of species diversity that take both measures into
account. One commonly used index is Shannon's index of diversity. To calculate this index, we must
know the total number of species in a community (n) and, for each species, the proportion of the
individuals in the community that represent that species (p). Once we have this information, we can
calculate Shannon's index (H) by taking the product of each proportion (p) and its natural logarithm
[In (P) and then summing these products, as indicated by the summation symbol (2):
H=-
SpIn (P)
Σ