Plant elemental diversity increases ecosystem productivity and temporal stability

Abstract The elemental composition of organisms (i.e., the elementome) directly constrains metabolic machinery and aligns with functional traits, linking organismal performance to nutrient cycling and energy flow at the ecosystem level. In theory, elemental diversity captures the community functional heterogeneity by quantifying variation in the multidimensional elementomes of co‐occurring species within a community. However, empirical evidence connecting organismal elemental diversity to ecosystem functioning and identifying its environmental controls remains scarce. We compiled an unprecedented dataset on plant elemental concentrations, encompassing more than 2500 species and 14 analyzed elements (including macronutrients, micronutrients, and trace elements) sampled from leaves, stems, trunks, and fine roots across 8 biomes and 72 sites, covering multiple ecosystem types including forests and grasslands. Using these data, we investigated the spatial patterns and drivers of plant elemental diversity and evaluated its relationship with ecosystem productivity and stability. Our results indicate that plant elemental diversity decreased with latitude, with interannual variability in temperature and mean annual precipitation as the primary controls on its spatial distribution. Moreover, ecosystems with higher plant elemental diversity exhibit greater efficiency in the use of carbon, water, and light, thereby translating into higher productivity and greater temporal stability across and within forests and grasslands, and these effects persisted even after accounting for climate and soil factors. Taken together, our results support the influence of plant elemental diversity as a distinct dimension of biodiversity with functional implications. Complementing trait‐ and taxonomy‐based measures, plant elemental diversity improves predictions of ecosystem productivity and temporal stability under ongoing climatic variability, and can substantially advance research on biodiversity and ecosystem functioning.