Manuel Delgado‐Baquerizo, Pankaj Trivedi, Chanda Trivedi, David J. Eldridge, Peter B. Reich, Thomas C. Jeffries, Brajesh K. Singh
Unlike for plants or animals, we have only a limited understanding of the relationships between microbial diversity and composition and ecosystem functioning, particularly in terrestrial environments. Microbes are by far the most abundant and diverse life forms on Earth, and play essential roles in maintaining multiple ecosystem functions including litter decomposition, primary production, soil fertility and gaseous emissions. However, we lack a quantitative understanding of the relative importance of microbial richness and composition in controlling multiple ecosystem functions simultaneously (multifunctionality). This knowledge gap limits our capacity to understand the influence of biotic attributes on the provision of the services and functions on which humans depend.
Here, we combined a regional field survey, and a microcosm experiment that manipulated the diversity of bacteria in two soils, to identify the role and relative importance of microbial richness and composition in predicting 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. Most importantly, our statistical models provided evidence that both microbial richness and composition influence multiple ecosystem functions. Overall, our findings advance our understanding of the mechanisms that underpin relationships between microbial diversity and ecosystem functionality in terrestrial ecosystems. They 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.
Image provided by authors.