Índice Shannon H
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
H = -Σp·ln(p)
About this calculator
The Shannon Diversity Index (H) is an ecological metric that quantifies species diversity in a habitat. It integrates two key factors: richness (number of species) and evenness (uniform distribution of individuals among species). The formula H = -Σp_i·ln(p_i) calculates the sum of each species' proportion (p_i) multiplied by the natural logarithm of that proportion, negated to ensure a positive value.
This index is widely used in conservation studies, ecosystem monitoring, and environmental impact assessments. For example, it can compare biodiversity between two forests or evaluate the recovery of a degraded environment. Higher H values indicate greater diversity, while lower values suggest dominance by few species.
When using the Shannon Index, ensure proportions (p_i) are calculated from accurate abundance data for each species. Sampling errors or biased data can lead to misleading results. Additionally, the index does not provide geographic distribution information, only relative diversity.
Frequently asked questions
What does the Shannon Index measure?
It measures species diversity in an environment by accounting for species richness and evenness.
How do I use the Shannon Diversity calculator?
Input the proportions (p_i) of each species in the habitat. The calculator will apply the formula H = -Σp_i·ln(p_i) automatically.
What does a high index value mean?
A high value indicates greater diversity, with many species and balanced individual distribution.
Can I compare results across different habitats?
Yes, as long as input data (proportions) are collected using consistent methods.
Why are my proportions not showing in the calculation?
Check if proportions sum to 100% (or 1) and use decimal format. Invalid values are automatically excluded.