 Species richness with regard to a given community, a group of interacting species in a given place, is the number of species present. We might also add species evenness to species richness (Magurran 1988, 2004). With respect to a given community, there will be some number of species. However, suppose we have two species in which the first has 300 members but the second has 700. Suppose again we have two species where the first has 500 members and the second 500 as well. The second community of species is far more “even” than the first. One formal representation of evenness is as follows (Magurran 1988). We start with the Shannon-Weiner diversity index.