Linking microbial body size to community co-occurrences and stability at multiple geographical scales in agricultural soils

Abstract

Body size determines individuals' life history and metabolic rates and thus, regulates community-level dynamics. However, whether body size mediates community co-occurrences and stability, especially in complex communities across different microbial trophic levels, remains unknown. Here, we investigate whether body size determines the co-occurrence pattern and stability of microbial communities across local, regional, and continental scales in the paddy soil ecosystems. Soil samples were collected from rice paddy fields at multiple spatial scales, and soil microbial communities were subsequently sequenced. The microorganisms were then divided into different groups based on taxonomic information at phylum/subphylum level, and the average body size of each microbial group was identified based on propagule size from documented literature. We examined the relationships between microbial body size and various community traits such as potential migration rate, co-occurrence pattern, cohesion, and community stability. Our results consistently showed that the small-sized microorganisms such as bacteria had significantly higher niche breadth, niche overlap and migration rate at various spatial scales. We found that microbial body size is consistently negatively correlated to negative co-occurrences and community stability. Our results, for the first time, put microbial body size into a broader community ecology framework, and contribute to a greater understanding of how microbial taxa with different body sizes would respond to future changes and perturbations.