Data from: Microbial richness and composition independently drive soil multifunctionality

Soil microbes provide multiple ecosystem functions such as nutrient
cycling, decomposition and climate regulation. However, we lack a
quantitative understanding of the relative importance of microbial
richness and composition in controlling multifunctionality. This knowledge
gap limits our capacity to understand the influence of biotic attributes
in the provision of services and functions on which humans depend. We used
two independent approaches (i.e. experimental and observational), and
applied statistical modeling to identify the role and relative importance
of bacterial richness and composition in driving multifunctionality (here
defined as seven measures of respiration and enzyme activities). In the
observational study we measured soil microbial communities and functions
in both tree- and bare soil-dominated microsites at 22 locations across a
1200 km transect in southeastern Australia. In the experimental study we
used soils from two of those locations and developed gradients of
bacterial diversity and composition through inoculation of sterilized
soils. Microbial richness and the relative abundance of γ-Proteobacteria,
Actinobacteria and Bacteroidetes were positively related to
multifunctionality in both the observational and experimental approaches;
however, only Bacteroidetes was consistently selected as a key predictor
of multifunctionality across all experimental approaches and statistical
models used here. Moreover, our results, from two different approaches,
provide evidence that microbial richness and composition are both
important, yet independent, drivers of multiple ecosystem functions.
Overall, our findings advance our understanding of the mechanisms
underpinning relationships between microbial diversity and ecosystem
functionality in terrestrial ecosystems, and further suggest that
information on microbial richness and composition needs to be considered
when formulating sustainable management and conservation policies, and
when predicting the effects of global change on ecosystem functions.