Shift in plant resource use strategies buffers against aridity-driven declines in grassland ecosystem multifunctionality

Drought is affecting grassland plant communities and ecosystem multifunctionality (EMF), but it remains uncertain how drought alters plant communities and, in turn, how such alterations affect EMF. To fill this gap, we examined the plant communities, soil properties and EMF along a natural gradient of aridity within the grassland ecosystems of northern China. As aridity intensified, plant species richness, multiple ecosystem functions (e.g., soil nutrient availability, above- and belowground biomass), and overall EMF declined ( P < 0.05), while community-level plant traits exhibited a marked tendency towards being more resource-conservative strategies. The changes included decreased plant height, leaf area and specific leaf area, accompanied by an increased leaf thickness. Both resource-conservative strategies (measured by community-level plant traits) and functional diversity promoted EMF, while shifts in plant resource use strategies buffered against aridity-induced declines in grassland EMF. These results reveal a coordinated shift in plant functional traits towards resource-conservative strategies under drought, enhancing drought resistance and maintaining multiple ecosystem functions. • Intensified aridity curtailed plant diversity and ecosystem multifunctionality (EMF). • Aridity reshaped community-level traits towards more resource-conservative strategies. • Trait-mediated shifts in plant resource-use strategies buffered aridity-induced declines in EMF.