Fig. 2. The AFD predicts the presence/absence of species from fluctuations of abundance.

a Relationship between fluctuation in abundance and the absence of species. The fluctuations of species abundances across communities (AFD) are Gamma distributed (Fig. 1), which implies that species are absent only because of finite sampling. b Tests the prediction, by comparing the occupancy of species (the fraction of communities where a species is presence) in different biomes with what expected from independent sampling from Gamma distributed relative abundances (Supplementary Note 4 and Supplementary Fig. 3).