Cross‐scale biogeochemical niche coordination links plant organs and community diversity

The elemental composition (i.e. elementome) of plants is tightly related to their function. The element‐based niche (biogeochemical niche) offers a powerful framework to understand the biodiversity‐ecosystem functioning relationship. Yet, how biogeochemical niche varies with organ, plant ecological strategy and diversity remains unknown across scales. Here, through extensive measurement of leaf and root elemental traits in 1465 individual trees from 242 species along a tropical elevational gradient, we explore the variation patterns of plant biogeochemical niche at the individual, species, and community levels. Leaf and root biogeochemical niches are positively correlated, and both are positively associated with leaf mass per area, suggesting that slow‐growing species tend to exhibit broader biogeochemical niches than fast‐growing ones; and all these results are consistent across the three ecological scales. At the community level, both leaf and root biogeochemical niches significantly increase with increasing phylogenetic diversity, but are not related to species richness and evenness. Synthesis . These findings provide a mechanistic basis for how functional differentiation in bioelements supports plant coexistence and community assembly.