Multifaceted diversity traits of crucial microbial groups in biological soil crusts promote soil multifunctionality

AbstractsMicrobial diversity is one of the most important drivers on ecosystem to maintain the simultaneous performance of functions (multifunctionality, MF) under climatic oscillation. However, existing studies typically consider taxonomic richness or Shannon index at the community level in which relations between diversity and functioning are not highly consistent. To disentangle the underlying linkages in real-world ecosystems, we conducted field investigation on biological soil crusts of Tibetan Plateau and evaluated multiple diversity facets (i.e., richness, evenness, and phylogeny-related trait dissimilarity) of carbon- and nitrogen-fixing functional groups (FGs). Seven crucial variables of soil functioning were also identified to calculate MF. We found that the integrated index, invoking multiple diversity components, was a stronger predictor on MF than richness. Moreover, the divergent performance of different diversity facets determined the idiosyncratic diversity effect of each FG on the MF. Namely, richness was the dominant factor for diazotrophs to maximize MF, whereas phylogenetic dissimilarity was the most important one for phototrophs. The heterogeneity among the focal FGs derived from the significant differentiation of the extent of multifunctional redundancy. Collectively, we speculated that the multifaceted diversity pattern depicts the response ability of crucial FGs by which biocrusts stabilize MF under environmental perturbation. Taken together, our results provided a perspective to bridge the gap between taxonomic and trait-based approaches for elucidating the biodiversity-ecosystem functioning relationship, and could ultimately help to boost the practices of dryland management against global change.