Fig. 6

Microbial co-occurrence networks are modular with fewer associations between bacterial taxa in surfaces than in cave communities. Nodes represent ASVs and connections represent associations between different ASVs. The sizes of the nodes indicate the geometric mean of the relative abundance of each ASV and colours represent bacterial phyla of the ASVs. Edge colours show positive (red) and negative (blue) associations. The lower panels provide different network properties, including the number of nodes (the number of ASVs that have associations with other ASVs), average degree per node ± SD (average number of interactions one ASV has with others; the error bars indicate the standard deviations), number of positive and negative associations between ASVs, number of communities (optimal division of network into sub-communities), modularity (strength of community division), and assortativity (testing whether similar nodes are interacting with each other)