Analyze counts, proportions, richness, and dominance accurately. Track Shannon, Simpson, evenness, and rare species effects. Built for field surveys, lab datasets, and biodiversity reviews.
Enter a community label, optional site details, and each species with its observed abundance value. Positive abundance rows are included automatically.
This example uses a total abundance of 100, making the percentage interpretation immediate and easy to verify.
| Rank | Species | Observed abundance | Relative abundance % |
|---|---|---|---|
| 1 | Oak | 34 | 34% |
| 2 | Pine | 21 | 21% |
| 3 | Fern | 15 | 15% |
| 4 | Grass | 14 | 14% |
| 5 | Moss | 9 | 9% |
| 6 | Shrub | 7 | 7% |
| Total | 100 | 100% | |
N = Σnipi = ni / N%RA = pi × 100H′ = −Σ[pi ln(pi)]D = Σ(pi2)1 − DJ′ = H′ / ln(S)d = Nmax / N(S − 1) / ln(N)S / √NDensity = ni / A when sample area is supplied.Here, ni is the abundance for species i, N is total abundance, S is observed richness, and A is sampled area.
Species abundance describes how many individuals, or how much measured abundance, belongs to each species within a sampled community. It helps reveal which species are dominant, common, or rare.
Richness counts how many species are present. Abundance measures how much each species contributes. Two sites can have identical richness but very different abundance distributions and ecological structure.
They summarize diversity from different angles. Shannon is sensitive to both richness and evenness, while Simpson emphasizes dominance and the probability that two observations belong to the same species.
Zero-valued rows are ignored in richness and diversity calculations. This keeps the results focused on species that actually contribute to the observed community abundance pattern.
Yes. Duplicate names are merged automatically, and their abundance values are added together. This helps when survey data comes from multiple subplots or field notes.
Use sample area when you want density estimates, such as individuals per square meter or biomass per hectare. Leave it blank when only proportional abundance is needed.
Yes. The calculator accepts any non-negative abundance measure. Counts are most common, but biomass, cover, or frequency values can also be analyzed when the same basis is used consistently.
Run each community separately, then compare richness, evenness, Shannon, Simpson, and the relative abundance graph. Similar totals can still hide large differences in dominance and rarity.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.