Figure 4.

Co-occurrence networks (a–c), node network roles (d–f), and alpha diversity indexers (g–i) of phyllosphere microbiota of camphor trees along the urbanization gradient. Suburban, developing, and urban stand for the corresponding urbanization level for sampling. Avg degree—average degree; Keystone node num—keystone node numbers; Edge num—edge numbers. Threshold value for node network roles: kinless hubs (z score > 2.5; c score > 0.62), provincial hubs (z score > 2.5; c score ≤ 0.62), connectors (z score ≤ 2.5; c score > 0.62), and peripherals (z score ≤ 2.5; c score ≤ 0.62) were defined according to their within-module degree (z score) and among-module degree (c score). An asterisk denotes a significant statistical difference between treatments (**, p < 0.01), and ns indicates that the statistical difference is not significant.