Use Morishita Index when you need to compute Morisita's dispersion index from three quadrat counts as 3 × Σni(ni − 1) divided by N(N − 1). Enter Quadrat A count, Quadrat B count, and Quadrat C count using the definitions and units below so the result can be reproduced.

Quadrat A count

An integer count or setting greater than or equal to 0, expressed in individuals.

Quadrat B count

An integer count or setting greater than or equal to 0, expressed in individuals.

Quadrat C count

An integer count or setting greater than or equal to 0, expressed in individuals.

The published tool contract uses this rule: Compute Morisita's dispersion index from three quadrat counts as 3 × Σni(ni − 1) divided by N(N − 1).

Morishita index

The calculated morishita index.

A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small.

Retain the original Quadrat A count, Quadrat B count, and Quadrat C count values and their units alongside the result. Brillouin Index is useful when you instead need to 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. Simpson Index D provides another view by helping you compute the Simpson diversity index D for three species counts in a sample.

• 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.

• Simpson Index D

  Compute the Simpson diversity index D for three species counts in a sample.

• Morisita-Horn Counts

  Quantify overlap between two communities over two species from raw abundance counts with the Morisita-Horn index.