Linking phylogenetic niche conservatism to soil archaeal biogeography, community assembly and species coexistence

Aim A predictive understanding of the mechanisms underlying microbial biogeographical patterns is of great interest, particularly with respect to phylogenetic distributions of their ecological adaptations. Here, we test whether phylogenetic information can predict the biogeographical distributions, community assembly and species co-occurrence of soil archaea. Location Northern China. Time period July and August 2017. Major taxa studied Archaeal communities. Methods By conducting a large-scale (transect intervals of 1,257.6 km) study across agricultural field, forest, wetland, grassland and desert biomes, we applied the phylogenetic framework of niche conservatism to investigate archaeal biogeography, community assembly and network topology. We examined the phylogenetic signal based on Blomberg's K to test whether the environmental preference of a given archaeal taxon was related to the phylogeny, corresponding to the degree of phylogenetic conservatism for environmental niches across complex environmental gradients. We evaluated the assembly processes of archaeal communities based on null model and Sloan neutral model analyses. We then explored the major factors that influenced the species coexistence and assembly processes of soil archaeal communities. Results Soil archaeal taxa exhibited strong climate-related niche conservatism of ecological preferences. Mean annual precipitation (MAP) had the strongest phylogenetic signal, and this mediated both community assembly processes and species coexistence, with stronger deterministic assembly and less species coexistence in environments with lower precipitation. Phylogenetic diversity was closely linked to the balance of community assembly processes; that is, stochastic assembly processes were dominant in low-diversity communities, whereas variable selection of deterministic processes promoted high phylogenetic diversity. Main conclusions We conclude that strong phylogenetic niche conservatism of soil archaea drives their biogeographical distributions. Our findings represent a considerable advance in linking phylogenetic niche conservatism to soil archaeal biogeography, community assembly and species coexistence, and therefore forecasting soil archaeal evolutionary adaptations in response to ongoing environmental changes.