Maintaining ecological stability is essential for sustaining ecosystem functions and the benefits they provide to society. Ecological theory predicts that plant diversity either stabilizes or destabilizes local populations, while empirical studies report variable effects. We hypothesize that this discrepancy arises to a meaningful extent from differences in the ecological processes captured by various diversity and stability metrics. Analyzing over 8,000 permanent vegetation plots across biomes on five continents, we found a negative (i.e., destabilizing) diversity–stability relationship when using abundance-weighted rather than unweighted measures of population stability, which are more influenced by dominant species. Similarly, cumulative richness—capturing total species occurrence over time and long-term turnover—reveals a stronger destabilizing effect compared to average annual richness. Our findings reveal that, when specific metrics of diversity and stability are considered, increased interspecific coexistence tends to destabilize populations across natural ecosystems worldwide—particularly those of dominant species.

We addressed the recent plea for a use of traits with a direct mechanistic link to drought tolerance to be considered in trait-based and global change ecology. On 122 herbaceous species covering a broad range of water availability conditions in temperate grasslands, we demonstrated the feasibility of the use of turgor loss point (πtlp), a key leaf drought tolerance trait that becomes operational for large-scale studies via the novel osmometry method. We investigated the coordination of this mechanistic trait with other commonly used proxies of drought tolerance. πtlpwas not or very weakly coordinated with the first two leading dimension of the global spectrum of form and function, plant height and specific leaf area. πtlp was tightly coordinated with intrinsic water use efficiency and leaf dry matter content. We suggest that stratification by plant functional types and/or accounting for species phylogeny might help to identify trait relationships that may be transferable among different systems.