Renkonen similarity index
The Renkonen similarity index (P), is a measure of dissimilarity between two communities (sites), based on relative (proportional) abundances p i = n i / ∑ n i {\displaystyle p_{i}=n_{i}/\sum {n_{i}}} of individuals of composite species. It was developed by the botanist Olavi Renkonen and published in 1938.
Source: Wikipedia — Renkonen similarity index (CC BY-SA 4.0)