Rarefaction Curve Calculator

Rarefaction is a statistical technique used to estimate species richness by standardizing samples to the same size. It corrects for bias in species counts due to unequal sampling effort and helps determine if sufficient sampling has been conducted.

A steep curve indicates many new species are still being discovered, suggesting more sampling is needed. A flattening curve suggests most species have been found and sampling effort may be adequate for the community.

Enter the abundance count for each species separated by commas. For example: 25,18,15,12,10,8,7,6,5,4 where each number represents how many individuals of that species were observed.

Species richness counts the number of different species. Shannon diversity considers both richness and evenness of species distribution. Simpson diversity emphasizes dominant species and is less sensitive to rare species.

Choose a subsample size smaller than your total sample size, typically the size of your smallest sample if comparing multiple communities. This allows standardized comparison across different sampling efforts.

Confidence intervals show the range of uncertainty around the expected species count. Wider intervals indicate greater uncertainty, often due to small sample sizes or highly uneven species distributions.

Rarefaction may not be suitable when samples have very different ecological conditions, when rare species are of particular interest, or when dealing with molecular data where low-abundance sequences may be artifacts.