Measure species counts quickly with flexible sample inputs. Review richness indices, totals, dominance, and evenness. Create charts, save exports, and explain results with confidence.
Enter a sample name, optional sampled area, and a list of species with abundance counts. Add or remove rows as needed.
This example helps you understand the expected input format and how abundance values are interpreted.
| Species | Abundance | Notes |
|---|---|---|
| Oak | 18 | Most abundant species in the sample. |
| Pine | 12 | Strong secondary presence. |
| Maple | 9 | Moderate contribution to diversity. |
| Birch | 5 | Lower abundance, still counted in richness. |
| Cedar | 3 | Rare in this sample but increases richness. |
Observed Species Richness: S = number of distinct species with abundance > 0
Total Individuals: N = Σ ni
Relative Proportion: pi = ni / N
Shannon Index: H' = -Σ (pi ln pi)
Simpson Diversity: 1 - Σ pi2
Pielou Evenness: J = H' / ln(S)
Menhinick Index: DMn = S / √N
Margalef Index: DMg = (S - 1) / ln(N)
Chao1 Estimate: SChao1 = S + F1² / (2F2) when doubletons exist, otherwise S + F1(F1 - 1)/2.
Here, F1 is the number of singleton species and F2 is the number of doubleton species.
Species richness measures how many distinct species are present in a sample. It does not account for how evenly individuals are distributed among those species.
Two samples can contain the same number of species but have very different abundance distributions. That is why diversity metrics like Shannon and Simpson are also shown.
No. A species must have abundance greater than zero to count toward observed richness. Zero rows are ignored in the final richness total.
Chao1 estimates unseen richness using rare species counts. It is helpful when your sample may not capture every species present in the larger population.
Enter area when you want density per unit area and richness per unit area. Leave it at zero or blank if your comparison does not use spatial normalization.
Yes. The calculator merges repeated species names and sums their abundances before computing results. This keeps the final metrics consistent and cleaner.
Observed richness only counts species number. Shannon and Simpson add abundance structure, helping you compare dominance, uncertainty, and evenness between samples.
Yes. It is suitable for ecology lessons, biodiversity exercises, applied statistics practice, and mathematical interpretation of proportions, logarithms, and index-based comparisons.
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.