Plant community stability is associated with a decoupling of prokaryote and fungal soil networks

Soil microbial networks play a crucial role in plant community stability. However, we lack knowledge on the network topologies associated with stability and the pathways that shape these networks. In a 13-year mesocosm experiment, we determined how natural grassland soil and soil abandoned from agricultural practices 60 years before the start of the experiment affected soil microbial network topologies. Abandoned arable soil promoted destabilising properties both above- and belowground. Aboveground, instability was associated with invading plant species reaching dominance. Belowground, instability was associated with soil microbial networks coupled in prokaryote and fungal responses, which were both shaped by a few, dominating plant community parameters. Conversely, in stable, natural grassland communities, soil prokaryote and fungal responses were decoupled. This decoupling was associated with different sets of plant community parameters shaping prokaryote and fungal niches. We conclude that plant community stability is associated with soil microbial networks with a high niche differentiation.