Use First Order Jackknife when you need to estimate species richness with the first order jackknife from unique species across incidence samples. Enter Observed species, Sample count, and Uniques using the definitions and units below so the result can be reproduced.

Observed species

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

Sample count

An integer count or setting greater than or equal to 1, expressed in samples.

Uniques

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

The published tool contract uses this rule: Estimate species richness with the first order jackknife from unique species across incidence samples.

Jackknife estimate

The calculated jackknife estimate 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 Observed species, Sample count, and Uniques values and their units alongside the result. Bootstrap Richness Proxy is useful when you instead need to compute the limited richness proxy Sobs + singletons divided by sample count. A full bootstrap richness estimator requires each species' observed incidence frequency. Rarefied Richness provides another view by helping you estimate rarefied species richness with the documented linear form sTotal x m / n for a subsample of m individuals drawn from n.

• Bootstrap Richness Proxy

  Compute the limited richness proxy Sobs + singletons divided by sample count. A full bootstrap richness estimator requires each species' observed incidence frequency.

• Rarefied Richness

  Estimate rarefied species richness with the documented linear form sTotal x m / n for a subsample of m individuals drawn from n.

• Margalef Richness

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