Use Rarefied Richness when you need to estimate rarefied species richness with the documented linear form sTotal x m / n for a subsample of m individuals drawn from n. Enter Total species, Total individuals, and Sample size using the definitions and units below so the result can be reproduced.

Total species

An integer count or setting greater than or equal to 1.

Total individuals

An integer count or setting greater than or equal to 1.

Sample size

An integer count or setting greater than or equal to 1.

The published tool contract uses this rule: Estimate rarefied species richness with the documented linear form sTotal x m / n for a subsample of m individuals drawn from n.^[1]

Rarefied richness

The calculated rarefied richness in species.

The output is an estimate tied to the stated model and coefficients; it is not a direct measurement and should retain that label when reported.

Retain the original Total species, Total individuals, and Sample size values and their units alongside the result. Rarefied Species Curve Point is useful when you instead need to estimate a rarefied species count with a documented half-saturation form: species total times sample over sample plus half-saturation, where the half-saturation defaults to the total individual count rounded up to its half. First Order Jackknife provides another view by helping you estimate species richness with the first order jackknife from unique species across incidence samples.

• Rarefied Species Curve Point

  Estimate a rarefied species count with a documented half-saturation form: species total times sample over sample plus half-saturation, where the half-saturation defaults to the total individual count rounded up to its half.

• First Order Jackknife

  Estimate species richness with the first order jackknife from unique species across incidence samples.

• Margalef Richness

  Compute the Margalef richness index from species count and total individuals.