Biodiversity Index Comparison Calculator

Simpson's diversity index measures the probability that two individuals randomly selected from a sample will belong to the same species. Lower values indicate higher diversity, with values ranging from 0 to 1.

The Shannon-Wiener index is calculated using H' = -Σ(pi × ln(pi)), where pi is the proportion of individuals belonging to species i. Higher values indicate greater diversity.

A high Simpson's index (close to 1) indicates low diversity, meaning the community is dominated by one or few species. Conversely, a low value indicates high diversity with many species present in similar proportions.

Shannon index is more sensitive to rare species and ranges from 0 to ln(S), while Simpson's index focuses on dominant species and ranges from 0 to 1. Shannon gives more weight to species richness, Simpson to species evenness.

Margalef richness index measures species richness by calculating (S-1)/ln(N), where S is the number of species and N is the total number of individuals. It accounts for sample size effects on species counts.

The evenness index (J') ranges from 0 to 1, with values closer to 1 indicating that species are more evenly distributed in abundance. It's calculated as H'/ln(S), showing how evenly individuals are distributed among species.

Choose based on your research focus: Shannon index for overall diversity including rare species, Simpson's for dominance patterns, Margalef for species richness, and evenness for distribution equality among species.