1. What is the Shannon Diversity Index?

The Shannon Diversity Index (H) is a measure of biodiversity that quantifies the uncertainty in predicting the species identity of an individual picked at random from a community. It accounts for both species richness and evenness.

2. How Does the Calculator Work?

The calculator uses the Shannon diversity index formula:

Where:

• \( p_i \) — Proportion of individuals belonging to species i
• \( \ln \) — Natural logarithm

Explanation: The index increases with both the number of species and the evenness of their distribution. Higher values indicate greater biodiversity.

3. Importance of Biodiversity Measurement

Details: The Shannon index is widely used in ecology to assess community diversity, monitor environmental changes, and compare biodiversity across different habitats or time periods.

4. Using the Calculator

Tips: Enter species proportions as comma-separated decimal values (e.g., 0.25,0.25,0.5). The sum of all proportions must equal 1.0, and all values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a good Shannon index value?
A: Typically ranges from 1.5 to 3.5. Values below 1.0 indicate low diversity, 1.0-3.0 moderate diversity, and above 3.0 high diversity.

Q2: How does this differ from Simpson's index?
A: Shannon index is more sensitive to rare species, while Simpson's index gives more weight to common species.

Q3: What are the limitations of this index?
A: It assumes random sampling and may be sensitive to sample size. It doesn't account for species identity or ecological importance.

Q4: Can I use percentages instead of proportions?
A: Yes, but convert percentages to proportions (divide by 100) and ensure the sum is 1.0.

Q5: What if my proportions don't sum to exactly 1.0?
A: The calculator requires proportions summing to 1.0 (±0.001 tolerance). Normalize your data if necessary.