Biodiversity Index Comparison Calculator

Biodiversity is measured in several different ways, and the Biodiversity Index Comparison Calculator runs five standard ecological indices at once so you can compare results side by side. Enter your number of species and the population count for each species to get the Shannon-Wiener Index, Simpson's Index, Simpson's Reciprocal, Margalef Richness, and Evenness Index — all calculated from the same sample data.

Total number of different species in your sample

Results

Shannon-Wiener Index (H')

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Simpson's Index (D)

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Simpson's Reciprocal (1/D)

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Margalef Richness

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Evenness Index (J')

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Total Individuals

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Results Table

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Frequently Asked Questions

What is Simpson's diversity index?

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.

How do I calculate Shannon-Wiener index?

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.

What does a high Simpson's diversity index indicate?

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.

What is the difference between Shannon and Simpson indices?

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.

What is Margalef richness index?

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.

How do I interpret the evenness index?

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.

Which biodiversity index should I use for my research?

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.