Fig. 5. The co-occurrence patterns among OTUs revealed by network analysis. (a) OTUs coloured by different subcommunities. AT: abundant taxa, RT: rare taxa, Inter: intermediate taxa. A connection indicates a very strong (Spearman’s r ≥ 0.7) and significant (FDR-adjusted P -value < 0.01) correlation. The size of each node is proportional to the number of connections (i.e., degree). Numbers inside parentheses represent the number of nodes belonging to the corresponding subcommunity. Numbers adjacent to nodes indicate the intra-associations within each subcommunity and numbers adjacent to edge connections represent inter-associations between different subcommunities. (b) Comparison of node-level topological features between different subcommunities. Different letters indicate the significant level at P < 0.05 level according to nonparametric Wilcoxon rank-sum test. OTUs coloured by (c) module and (d) phylum-level taxonomy. Percentages within parentheses indicate percent of nodes belong to each group.
Table 1 Mantel tests for the correlation between environmental variables and βNTI of abundant and rare taxa.