Calculate species diversity and community dominance.
Species Counts
Diversity Analysis
0.7353
Index of Diversity (1 - D)
Probability that two individuals are different species
High Diversity Habitat
Reciprocal Index3.78Effective Species
Similarity Index (D)0.2647Prob. Same Species
Total Population (N)52
Species Richness (S)5
About this calculator
Understanding Simpson's Index
Simpson's Index (D) measures the probability that two individuals randomly selected from a sample will belong to the same species. The "Index of Diversity" (1-D) represents the probability that two individuals belong to different species, with higher values indicating higher diversity.
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Pro Tips
A value of 1-D close to 1 indicates high diversity (many species, even distribution).
A value of 1-D close to 0 indicates low diversity (dominated by one or few species).
Reciprocal Index (1/D) represents the 'effective' number of species.
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Fun Facts
"This index was published by E.H. Simpson in 1949."
"It is mathematically identical to the Herfindahl-Hirschman Index in economics."
"A score near 1.0 (1-D) indicates a rich, stable ecosystem."
"Ecologists use this to compare habitat stability over time."
