Fig. 1: Definition and composition of abundant, intermediate, and rare taxa.

a Cutoff values for defining abundant, intermediate, and rare taxa based on the average relative abundance across all samples. b, c Number of ASVs and relative abundance for the three biological groups across all samples. d The proportion of samples occupied for each of abundant, intermediate, and rare ASVs. e Taxonomic distribution of the three biological groups at phylum level. The thickness of each ribbon in the circos plot represents the relative abundance of the three biological groups assigned to different phyla. f, g Boxplots of the niche breadth for each ASV within abundant (n = 601), intermediate (n = 4507), and rare taxa (n = 19,969) estimated using the Levins’ index and the tolerance index, respectively. The different letters above the boxes represent significant differences determined by the Kruskal–Wallis test followed by Dunn post-hoc test (Bonferroni correction).