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.