1. Plants are enormously diverse in their traits and ecological adaptation, even within given ecosystems, such as tropical rainforests. Accounting for this diversity in vegetation models poses serious challenges. Global plant functional trait databases have highlighted general trait correlations across species that have considerably advanced this research program. However, it remains unclear whether trait correlations found globally hold within communities, and whether they extend to drought tolerance traits.
2. For 134 individual plants spanning a range of sizes and life forms (tree, liana, understory species) within an Amazonian forest, we measured leaf drought tolerance (leaf water potential at turgor loss point, π_tlp), together with 17 leaf traits related to various functions, including leaf economics traits and nutrient composition (leaf mass per area, LMA; and concentrations of C, N, P, K, Ca, and Mg per leaf mass and area), leaf area, water use efficiency (carbon isotope ratio), and time-integrated stomatal conductance and carbon assimilation rate per leaf mass and area. We tested trait coordination and the ability to estimate π_tlp from the other traits through model selection. Performance and transferability of the best predictive model were assessed through cross-validation.
3. π_tlp was positively correlated with leaf area, and with N, P and K concentrations per leaf mass, but not with LMA or any other studied trait. Five axes were needed to account for >80% of trait variation, but only three of them explained more variance than expected at random. The best model explained only 30% of the variation in π_tlp, and out-sample predictive performance was variable across life forms or canopy strata, suggesting a limited transferability of the model.
4. Synthesis. We found a weak correlation among leaf drought tolerance and other leaf traits within a forest community. We conclude that higher trait dimensionality than assumed under the leaf economics spectrum may operate among leaves within plant communities, with important implications for species coexistence and responses to changing environmental conditions, and also for the representation of community diversity in vegetation models.

All methods and analyses are explicitely described and provided in the corresponding paper.

Please refer to the corresponding paper published in Journal of Ecology for further details.