New publication from Hong et al. in PNAS: Mechanistic links between coexistence, productivity, and stability in experimental grasslands

For decades, ecologists have been intrigued by two fundamental interlinked questions: what enables species to coexist, and how does the diversity of coexisting species influence ecosystem functioning? Our research provides a unified answer. Data from long-term grassland experiments reveal that conditions allowing species to live together also tend to make ecosystems more productive and stable. These positive relationships can be explained by shared ecological drivers. Differences in evolutionary history and plant traits reduce competition, thereby simultaneously promoting species coexistence and productivity. Ecosystems dominated by plants that form strong mutualisms with soil fungi exhibit both enhanced productivity and stability. These findings suggest a clear conservation strategy: sustaining biodiverse, productive, and stable ecosystems depends on promoting both phylogenetic and functional trait diversity.

Abstract

The escalating biodiversity crisis underscores the urgent need for a unified framework that links the mechanisms maintaining biodiversity to its functional consequences. However, studies of species coexistence and biodiversity effects on ecosystem functioning have largely progressed independently. Here, using long-term data from five grassland biodiversity experiments, we quantified “coexistence potential” (i.e., the degree to which niche differences exceed fitness differences) and tested its relationships with biodiversity effects on both ecosystem productivity (via complementarity and selection effects) and stability (via species asynchrony and species stability). We found that the relationships within the coexistence–productivity–stability triad were overall positive. These patterns were mechanistically explained by phylogenetic and trait composition: Phylogenetically and functionally more diverse communities supported higher coexistence potential and greater productivity, while those dominated by species with stronger root-mycorrhizal collaboration and larger seeds exhibited enhanced productivity and stability. Our work provides integrative empirical evidence linking biodiversity maintenance to ecosystem functioning, demonstrating that conserving phylogenetically and functionally diverse communities, particularly those including collaborative species, is key to sustaining biodiverse, productive, and stable ecosystems.

Reference:

Hong, P., B. Schmid, D. Craven, M. Liang, M. Luo, et al. 2026. Mechanistic links between coexistence, productivity, and stability in experimental grasslands. Proceedings of the National Academy of Sciences 123:e2602893123. https://doi.org/10.1073/pnas.2602893123.