A trait-based approach for examining microbial community assembly

Abstract:

Microorganisms regulate all of Earth’s major biogeochemical cycles and an understanding of how microbial communities assemble is a key part in evaluating controls over many types of ecosystem processes. Rapid advances in technology and bioinformatics have led to a better appreciation for the variation in microbial community structure in time and space. Yet, advances in theory are necessary to make sense of these data and allow us to generate unifying hypotheses about the causes and consequences of patterns in microbial biodiversity and what they mean for ecosystem function. Here, I will present a metaanalysis of microbial community assembly from a variety of successional and post-disturbance systems. Our analysis shows various distinct patterns in community assembly, and the potential importance of nutrients and dispersal in shaping microbial community beta diversity in these systems. We also used a trait-based approach to generate hypotheses about the mechanisms driving patterns of microbial community assembly and the implications for function. Our work reveals the importance of rRNA operon copy number as a community aggregated trait in helping to reconcile differences in community dynamics between distinct types of successional and disturbed systems. Specifically, our results demonstrate that decreases in average copy number can be a common feature of communities across various drivers of ecological succession, supporting a transition from an r-selected to a K-selected community. Importantly, our work supports the scaling of the copy number trait over multiple levels of biological organization, from cells to populations and communities, and has implications for both ecology and evolution. Trait-based approaches are an important next step to generate and test hypotheses about the forces structuring microbial communities and the subsequent consequences for ecosystem function.