Rarefaction (ecology)

In ecology, rarefaction is a technique to assess species richness from the results of sampling.

[2] The technique of rarefaction was developed in 1968 by Howard Sanders in a biodiversity assay of marine benthic ecosystems, as he sought a model for diversity that would allow him to compare species richness data among sets with different sample sizes; he developed rarefaction curves as a method to compare the shape of a curve rather than absolute numbers of species.

[4] Following initial development by Sanders, the technique of rarefaction has undergone a number of revisions.

[5] The issue of overestimation was also dealt with by Daniel Simberloff, while other improvements in rarefaction as a statistical technique were made by Ken Heck in 1975.

Most commonly, the number of species is sampled to predict the number of genera in a particular community; similar techniques had been used to determine this level of diversity in studies several years before Sanders quantified his individual to species determination of rarefaction.

[2] Rarefaction techniques are used to quantify species diversity of newly studied ecosystems, including human microbiomes, as well as in applied studies in community ecology, such as understanding pollution impacts on communities and other management applications.

Rarefaction curves produce smoother lines that facilitate point-to-point or full dataset comparisons.

The sample-based approach accounts for patchiness in the data that results from natural levels of sample heterogeneity.

[8] Rarefaction only works well when no taxon is extremely rare or common[citation needed], or when beta diversity is very high.

A true measure of diversity accounts for both the number of species present and the relative abundance of each.