Soil bacterial networks are less stable under drought than fungal networks

TLDR

Soil microbial communities are essential for ecosystem functioning, yet the response of their co‑occurrence networks to climate extremes such as drought remains unknown. In grassland mesocosms, drought destabilizes bacterial co‑occurrence networks while leaving fungal networks stable, and the resulting bacterial community shifts—mediated by vegetation changes and reduced soil moisture—have stronger links to soil function during recovery and may influence long‑term plant community composition and ecosystem resilience.

Abstract

Abstract Soil microbial communities play a crucial role in ecosystem functioning, but it is unknown how co-occurrence networks within these communities respond to disturbances such as climate extremes. This represents an important knowledge gap because changes in microbial networks could have implications for their functioning and vulnerability to future disturbances. Here, we show in grassland mesocosms that drought promotes destabilising properties in soil bacterial, but not fungal, co-occurrence networks, and that changes in bacterial communities link more strongly to soil functioning during recovery than do changes in fungal communities. Moreover, we reveal that drought has a prolonged effect on bacterial communities and their co-occurrence networks via changes in vegetation composition and resultant reductions in soil moisture. Our results provide new insight in the mechanisms through which drought alters soil microbial communities with potential long-term consequences, including future plant community composition and the ability of aboveground and belowground communities to withstand future disturbances.