The multidimensional plant diversity‒productivityrelationship across resource diversity gradients in the grasslands of the Tibetan Plateau

Understanding how biodiversity influences ecosystem productivity (BPR) remains a central question in ecology, yet a predictive understanding is hampered by the inconsistent relationships observed across different environments. Environmental condition, particularly in resource availability, is increasingly recognized as a key factor modulating BPR. However, empirical evaluations integrating multiple resource dimensions remain scarce.In this study, we quantified Resource Diversity (RD) —an integrative index reflecting the joint variability of multiple co-limiting resources—and evaluated its role in shaping the biodiversity–productivity relationship across alpine grasslands of the Tibetan Plateau. By linking multidimensional biodiversity (taxonomic, functional, and phylogenetic) to RD, we demonstrate that the strength and direction of biodiversity effects on productivity systematically vary along RD gradients. Our findings highlight RD as a mechanistic environmental context that governs the functional role of biodiversity, offering a quantitative framework to understand BPR context-dependency at large spatial scales.