Species Diversity Index Calculator

Calculator

Enter species names and observed counts. Duplicate species names are automatically merged.

Shannon log base

Evenness uses ln(S), regardless of display base.

Include zero-count species

Proportions still use positive counts only.

Results appear above this form after submission.

Species and counts

#	Species	Count	Del
1
2
3
4
5

Tip: Use integers for counts. Blank rows are ignored.

Optional paste import

Paste CSV-style lines. They are appended to the table on submit.

Example data table

A small woodland survey (5 species).

Species	Count
Oak	18
Pine	12
Maple	9
Birch	6
Elm	3

Click “Load example” to copy these values.

Formulas used

Let N be total individuals, S be observed species, and p_i=n_i/N.

Shannon diversity: H′ = −Σ p_i ln(p_i). If base-10 is selected, H′ = −Σ p_i log₁₀(p_i).
Simpson concentration: D = Σ p_i².
Simpson diversity: 1 − D.
Simpson reciprocal: 1/D.
Evenness (Pielou): J = H′_ln / ln(S).
Margalef richness: (S − 1) / ln(N).
Menhinick richness: S / √N.

How to use this calculator

Enter each species name and its observed count.
Choose the Shannon log base you want to report.
Click Calculate diversity to generate results.
Review the abundance table to confirm p_i values.
Use CSV for analysis, and PDF for quick sharing.

FAQs

1) Which index should I report for publications?

Shannon H′ is widely reported for overall diversity. Simpson 1−D emphasizes dominance patterns. Many studies report both, plus S and N for transparency.

2) What does evenness J tell me?

Evenness compares observed H′ to the maximum possible for S species. Values near 1 suggest similar abundances. Lower values indicate dominance by a few species.

3) Can I include species with zero observations?

You can keep zero-count species for display consistency. However, proportions and diversity metrics rely on observed individuals. Including many zeros can confuse comparisons between surveys.

4) Why does merging duplicate names matter?

Field notes often repeat a species across transects or sheets. Merging duplicates prevents double-counting species richness and produces correct totals for N and p_i.

5) Is log base important for Shannon H′?

Changing the log base rescales H′ but keeps the same ordering of sites. Use the same base when comparing values across reports. Evenness here is standardized with natural logs.

6) What causes Simpson reciprocal to be very large?

When many species have similar abundances, D becomes small, and 1/D increases. It can be interpreted as the effective number of common species in the community.

7) How can I compare two habitats fairly?

Use similar sampling effort and consistent identification. Compare multiple metrics together: S, N, H′, 1−D, and evenness. Report methods and uncertainty where possible.