Unraveling community assembly mechanisms is a central goal of current microbial ecology researches, but how to precisely quantify the importance of different ecological processes remains a big challenge. We developed a novel method to infer community assembly mechanism by phylogenetic-bin-based null model analysis, considering different microorganisms can be under different assembly mechanisms. This approach showed better quantitative and qualitative performance, particularly higher precision and sensitivity, in estimating relative importance of different ecological processes in simulated communities.
Results/Conclusions
It is critical to understand whether and how temperature drives community assembly at large scale within the context of global climate change. Thus, we applied the new approach to analyze bacterial, fungal, and nitrogen-fixing bacterial (NiFB) communities in North America forest soils. The influence of selection and dispersal showed significant change along geographic distance supporting our biogeographic hypotheses of ecological processes. Across bacteria, fungi, and NiFB, temperature always showed much stronger association and more direct contribution to the major ecological processes than all other tested factors. In contrast, other factors showed smaller or specific effects on ecological processes. The biogeographic significance of temperature implies the future change of temperature distribution may have significant impact on soil microbial community assembly.