The Renkonen similarity index (P), is a measure of dissimilarity between two communities (sites), based on relative (proportional) abundances of individuals of composite species. It was developed by the botanist Olavi Renkonen and published in 1938.
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- percentage structure of one set,
- percentage structure of second set.
The codomain of this distance function ranges from 1 (identical proportional abundances) to 0 (no taxa shared).