Ecological memory of recurrent drought modifies soil processes via changes in soil microbial community

Climate change is altering the frequency and severity of drought events. Recent evidence indicate that drought may produce legacy effects on soil microbial communities. However, it is unclear whether precedent drought events lead to ecological memory formation, which is the capacity of past events to influence current ecosystem response trajectories. Here, we utilize a long-term field experiment with a unique experimental layout comparing 10 years of recurrent drought events to a single drought event in a grassland soil. We show ecological memory formation of microbially mediated soil processes in response to drought when the system is subjected to a history of drought events. Recurrent droughts shift the microbial community composition and putative community function compared to control and single drought event. We conclude that an ecological memory of drought in soil processes is caused by a shift in microbial community composition, which in turn buffer soil functionality against drought effects.