Calculateur de Diversité des Espèces Gratuit
Calculez les indices de diversité des espèces. Évaluez la richesse et l'équitabilité de la biodiversité d'un écosystème.
Shannon Diversity Index
1.842 H'
Shannon Diversity Index vs Number of Species
Formule
How to Calculate Species Diversity
The Shannon Diversity Index (H') measures both species richness and evenness of distribution.
Formula
H' = -Sum(pi * ln(pi)) for each species
Simplified: H' = ln(S) * J
Where S = number of species, J = evenness (0-1)
Interpretation
Exemple Résolu
A habitat with 10 species, 200 total individuals, and 0.8 evenness.
- 01Max diversity: ln(10) = 2.303
- 02Shannon index: 2.303 * 0.8 = 1.842
- 03Average per species: 200 / 10 = 20 individuals
- 04This indicates moderate diversity
Questions Fréquentes
What is the Shannon Diversity Index?
The Shannon Index (H') combines species richness (number of species) and evenness (how equally individuals are distributed). Higher values indicate more diverse communities.
Why does evenness matter?
A habitat with 10 species where 90% are one species is less functionally diverse than one where all 10 species are equally represented. Evenness captures this distinction.
What is a healthy level of biodiversity?
It depends on the ecosystem. Tropical forests may have H' > 4, while tundra naturally has H' < 1. The concern is when diversity decreases relative to historical levels.