Fig. 6

Quantitative estimation of the contribution of ecological drivers to community assembly. A Net relatedness Index was (betaNRI) was calculated as a standardized measure of mean phylogenetic distance to the nearest taxon in the community at each site. Letters denote significant between associations (P < 0.001). B The beta nearest taxon index (betaNTI) was calculated to infer contribution to ecological convergence or divergence using Raup-Crick null models (RCbray) for different spatial scales: overall (province), region, location, site (arrows denote major shifts due to spatial scale); and for the different ecological guilds (photosynthetic, chemoautotrophic, and chemoheterotrophic) overall