Calculate Shannon-Wiener diversity index (H), Shannon equitability (evenness), species richness, Simpson's index, and total individuals from species abundance data for ecological research and education.
Add species names and the number of individuals observed. The calculator will compute multiple biodiversity indices automatically.
A tropical forest with 5 tree species: Oak (25), Maple (18), Pine (30), Birch (12), Cedar (15). H' โ 1.56, Evenness โ 0.97, indicating very even species distribution with high diversity.
A desert with 3 species: Creosote (85), Cactus (8), Yucca (7). H' โ 0.63, Simpson's D โ 0.65, showing one dominant species with low overall diversity.
A healthy reef with 6 coral species: Brain Coral (40), Staghorn (35), Elkhorn (28), Plate (22), Fire (18), Fan (15). H' โ 1.73, Simpson's D โ 0.19, demonstrating high biodiversity.
A farm with 4 species: Wheat (200), Clover (15), Dandelion (8), Thistle (5). H' โ 0.45, Evenness โ 0.32, showing a highly skewed distribution dominated by one crop.
A park with 4 bird species: Sparrow (45), Robin (30), Blue Jay (22), Cardinal (18). H' โ 1.31, Simpson's D โ 0.28, representing a moderately diverse community.
8 microbial species with counts: Species A (12), B (10), C (9), D (8), E (7), F (6), G (5), H (4). H' โ 2.02, Richness = 8, showing how species count impacts the Shannon index.
H' = โฮฃ(pi ร ln(pi))
Where pi = ni / N (proportion of species i), ni = count of species i, N = total individuals. Higher values indicate greater diversity.
E = H' / ln(S)
Where S = species richness (total number of species). Values close to 1 indicate even distribution of individuals among species.
D = ฮฃ(ni(niโ1)) / (N(Nโ1))
Measures the probability that two individuals randomly selected belong to the same species. Lower values indicate higher diversity.
S = count of distinct species
The simplest biodiversity measure โ just the number of different species present in your sample or community.
Use the Shannon index when you care about both richness and evenness. Use Simpson's index when you want a measure less sensitive to rare species. Use richness when counting species presence/absence.
Biodiversity indices are most useful for comparing communities. Higher Shannon values and lower Simpson values typically indicate healthier, more diverse ecosystems. Always compare samples of similar size when possible.
Larger sample sizes tend to capture more species and give more reliable index values. The Shannon index is somewhat sensitive to sample size, while Simpson's index is more robust. Consider using rarefaction curves for rigorous comparison.
Expected biodiversity varies by ecosystem. Tropical rainforests typically have high diversity (H' > 3), while temperate forests are moderate (H' 1.5-3), and deserts or agricultural fields show lower values (H' 0.5-1.5).
Biodiversity refers to the variety of life forms in a given habitat or ecosystem. It encompasses species diversity (the number and abundance of different species), genetic diversity (variation within species), and ecosystem diversity (the variety of habitats and ecological processes). Scientists use biodiversity indices to quantify and compare the diversity of different communities, track changes over time, and assess the health of ecosystems. These indices are fundamental tools in ecology, conservation biology, environmental monitoring, and natural resource management.
The Shannon-Wiener index (also called the Shannon-Weaver index or simply the Shannon index) is one of the most widely used measures of species diversity. It was developed by Claude Shannon in the context of information theory and later adapted for use in ecology by Robert MacArthur. The index assumes that individuals are randomly sampled from a theoretically infinite population and accounts for both species richness and evenness. Values typically range from 0.5 to 5, where higher values indicate greater diversity. The index is calculated as H' = โฮฃ(pi ร ln(pi)), where pi is the proportion of individuals belonging to species i.
Shannon equitability, also known as Pielou's evenness index, measures how evenly individuals are distributed among the species present. It is calculated as E = H' / ln(S), where S is species richness. Values range from 0 to 1, with 1 representing perfect evenness (all species have the same abundance). A low evenness value indicates that one or a few species dominate the community, while a high value suggests a more balanced distribution. This metric is particularly useful when comparing communities with the same species richness but different abundance patterns.
Simpson's index, proposed by Edward H. Simpson in 1949, measures the probability that two randomly selected individuals from a community belong to the same species. The formula D = ฮฃ(ni(niโ1)) / (N(Nโ1)) accounts for finite population sampling. Values range from 0 to 1, where 0 represents infinite diversity (no two individuals are the same species) and 1 represents no diversity (all individuals belong to one species). Unlike the Shannon index, Simpson's index is more sensitive to changes in the abundance of common species and less sensitive to rare species, making it a complementary measure for diversity assessment.
Biodiversity indices help conservation biologists identify high-priority areas for protection. Sites with higher Shannon or lower Simpson indices typically harbor more diverse communities and may be designated as reserves, protected areas, or biodiversity hotspots requiring conservation intervention.
Regular biodiversity assessments track ecosystem health over time. Declining diversity indices may signal environmental degradation, pollution impacts, habitat fragmentation, or the effects of climate change. Increasing indices can indicate successful restoration efforts.
Farmers and agricultural scientists use biodiversity indices to evaluate the ecological health of farmlands. Higher diversity of beneficial insects, soil organisms, and pollinator species correlates with more sustainable agricultural practices and better ecosystem services.
Researchers use diversity indices to test hypotheses about community structure, species interactions, and ecosystem function. Comparing indices across different habitats, treatments, or time periods reveals patterns in how communities are organized and respond to change.
Each biodiversity index captures different aspects of community structure. The Shannon index is sensitive to changes in both richness and evenness, making it a good all-around measure. Simpson's index is weighted toward the most abundant species, making it useful for detecting changes in dominant species. Species richness is the simplest measure but doesn't account for abundance patterns. Evenness specifically measures how abundances are distributed. For a comprehensive ecological assessment, ecologists often report multiple indices together, as each provides unique insight into community structure. Using all five output metrics from this calculator gives you a complete picture of biodiversity at your study site.
Our Biodiversity Index Calculator makes it easy to compute multiple diversity metrics from your species abundance data. Follow these simple steps to analyze your community data:
The calculator uses standard ecological formulas with natural logarithms (base e) for the Shannon index. All calculations are performed in your browser โ no data is sent to any server, ensuring your research data remains private and secure. The tool supports any number of species rows, from a simple two-species comparison to complex community datasets with dozens of species.
Our Biodiversity Index Calculator is designed for ecology students, researchers, environmental scientists, conservation biologists, and anyone interested in quantifying species diversity. It computes five key biodiversity indices simultaneously โ Shannon-Wiener Index (H'), Shannon Equitability (Evenness), Species Richness (S), Total Individuals (N), and Simpson's Index (D) โ using standard ecological formulas. The dynamic species input allows you to work with datasets of any size, from simple classroom exercises to complex field survey data.
Get all major biodiversity indices in a single calculation โ no need to switch between different tools or manually compute formulas. The calculator displays Shannon H', evenness, richness, total counts, and Simpson's D together.
Add as many species as your dataset requires. The dynamic row system supports everything from a few species to dozens, making it suitable for both simple educational examples and professional research.
Built-in examples for different ecosystem types help you understand what your index values mean. Compare your results to tropical forests, deserts, coral reefs, and agricultural fields for ecological context.
All calculations are performed in your browser using JavaScript. No species data, abundance counts, or results are sent to any server. Your ecological research data remains completely private and secure.
Important Disclaimer: This Biodiversity Index Calculator provides estimates for informational and educational purposes only. While the formulas used are standard in ecology, the interpretation of biodiversity indices requires professional ecological knowledge and consideration of site-specific factors. Sample size, sampling methodology, and taxonomic resolution can all affect index values. This tool is not a substitute for professional ecological consulting or peer-reviewed research methodology. Always consult with qualified ecologists or conservation professionals for critical biodiversity assessments.