Contrasting assembly processes in a bacterial metacommunity along a desiccation gradient

Abstract

Understanding the relative influence of deterministic and stochastic processes in driving community assembly is a major goal in microbial ecology. Here, we have investigated the influence of these processes on bacterial community assembly in the lateral sediments of a salt pan along a desiccation gradient over a three-year period. We show that the role of deterministic processes increases in communities distant from the waterline (shaped by drought), probably as a result of the interplay between abiotic and biotic factors. By contrast, the influence of stochastic processes on bacterial community assembly was higher in the sediments closest to the waterline ,more likely due to lower levels of abiotic stress.Our results demonstrate that both deterministic and stochastic processes influence bacterial community assembly in salt pan sediments, and that their relative influence varies along a desiccation gradient.