Functional dominance outperforms functional diversity in driving ecosystem multifunctionality during vegetation restoration in a desert steppe

Abstract Sand-fixing vegetation established in northern China has effectively reversed land degradation and enhanced biodiversity. However, how species and functional diversity affect ecosystem multi unctionality (EMF) during vegetation restoration in desert stepps remains unclear. We surveyed plant communities, 18 soil properties and 15 leaf and root traits across four restoration stages in the Mu Us Desert, northern China. We quantified plant diversity and EMF index that integrated multiple ecosystem properties related to productivity, nutient storage, nutrient cycling and water storage. With vegetation restoration, species richness increased significantly, whereas species evenness and functional diversity declined. Concurrently, variations in community-weighted means (CWM) of traits indicated a transition from conservative to resource-acquisitive strategies. Ecosystem functions related to productivity, nutrient storage, and water storage improved markedly, leading to a significant enhancement of EMF, whereas nutrient cycling rates remained unchanged. EMF was positively associated with species richness and CWM traits, but negatively associated with species evenness and functional dispersion. Among these factors, CWM traits had the strongest effect on EMF, underscoring the dominant role of resource-acquisitive species. Our findings highlighted that dominant resource-acquisitive species play a key role in driving coordinated improvements across multiple ecosystem functions during vegetation restoration, and suggested that restoration programmes should integrate both species- and trait-based diversity metrics to optimize EMF in desert steppes.