Morisita-Horn Counts
Quantify overlap between two communities over two species from raw abundance counts with the Morisita-Horn index.
Description
Quantify overlap between two communities over two species from raw abundance counts with the Morisita-Horn index.
Morisita-Horn Counts is a focused biology tool that quantify overlap between two communities over two species from raw abundance counts with the Morisita-Horn index. It calculates locally from the values you enter and exposes the result without changing the source observations.1
When to use Morisita-Horn Counts
Use Morisita-Horn Counts when you need to quantify overlap between two communities over two species from raw abundance counts with the Morisita-Horn index. Enter Community A species 1 count, Community A species 2 count, Community B species 1 count, and Community B species 2 count using the definitions and units below so the result can be reproduced.
- Community A species 1 count
- An integer count or setting greater than or equal to 0, expressed in individuals.
- Community A species 2 count
- An integer count or setting greater than or equal to 0, expressed in individuals.
- Community B species 1 count
- An integer count or setting greater than or equal to 0, expressed in individuals.
- Community B species 2 count
- An integer count or setting greater than or equal to 0, expressed in individuals.
How Morisita-Horn Counts calculates the result
The published tool contract uses this rule: Quantify overlap between two communities over two species from raw abundance counts with the Morisita-Horn index.
- Morisita-Horn index
- The calculated morisita-horn index.
Limitations of Morisita-Horn Counts
The calculation does not propagate measurement uncertainty, sampling error, or biological and chemical variability.
Alternative or Complementary measurements
Retain the original Community A species 1 count, Community A species 2 count, Community B species 1 count, and Community B species 2 count values and their units alongside the result. Morisita-Horn Overlap is useful when you instead need to compare two communities with the Morisita-Horn similarity coefficient for two categories. Each pair of proportions must sum to one; zero means no shared composition and one means identical composition. Jaccard Index provides another view by helping you compute the Jaccard similarity index between two species counts.
References
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Morisita's overlap index — Wikipedia contributors
Similar or alternative tools
- Morisita-Horn Overlap
Compare two communities with the Morisita-Horn similarity coefficient for two categories. Each pair of proportions must sum to one; zero means no shared composition and one means identical composition.
- Jaccard Index
Compute the Jaccard similarity index between two species counts.
- Brillouin Index
Compute the Brillouin diversity index HB = (ln(N!) - sum(ln(ni!))) / N from three species counts using loop-based log factorials for communities up to 10000 individuals.