Raw data associated with the article "Interactions between nutrient levels and fluctuations shape soil microbial legacies and mediate non-native plant growth"

Resource variability has multiple dimensions, and its complexity is intensifying under global change. While elevated resource levels and temporal fluctuations often promote non-native plant invasions, it remains unclear how these factors influence invasion success through soil microbial communities, which are key responders to resource change and regulators of plant performance. We conducted a two-phase greenhouse experiment to address this knowledge gap. In phase I, we conditioned soils with six 4-species assemblages of native plants under factorial combinations of nutrient level (low or high) and fluctuation regime (constant or pulsed), and characterized their soil microbial communities with high-throughput sequencing. In phase II, we grew ten non-native plant species individually with soil inocula from phase I. Nutrient level and fluctuation interacted to generate distinct microbial legacies that altered non-native plant growth. Under low nutrients, pulsed additions produced microbial legacies that significantly suppressed non-native growth compared with constant additions, whereas under high nutrients, legacy effects did not differ between fluctuation regimes. Shifts in arbuscular mycorrhizal fungal relative abundance and richness appeared to drive these patterns while pathogens did not. Our findings demonstrate that resource variability can influence non-native plants indirectly via microbial legacies, with effects depending on the interactions between resource level and temporal fluctuation. By showing that low-nutrient pulses create inhibitory microbial legacies, this study offers a novel explanation for inconsistent effects of resource fluctuations on invasions and underscores the need to incorporate historical resource conditions into invasion predictions under global change.