New publication from Roscher et al. in Journal of Ecology: Plant species with ‘fast’ traits are winners in young and high-diversity plant communities

Long-term biodiversity experiments have shown increasing strengths of positive biodiversity–productivity relationships over time, while the species-level responses to increased plant diversity are highly variable. Plant–soil interactions and resource-use complementarity offer the potential to explain both overyielding and underyielding in diversity–productivity relationships. However, it is not well understood how community history, that is changing biotic interactions over time, modulates the growth of individual species and whether ‘winners’ (i.e. overyielding species) and ‘losers’ (i.e. underyielding species) differ in their traits.
We first used above-ground biomass data of 66 plant mixtures (with 2, 4, 8, 16 and 60 species) of a long-term biodiversity experiment (Jena Experiment) to identify plot-specific ‘winners’ and ‘losers’. Using a subset of two winner and two loser species from each mixture, we then planted individuals (= ‘phytometers’) in resident communities with different histories, that is 14-year ‘old communities’ and ‘new communities’ on new soil, and measured their performance and traits related to the fast–slow leaf economic trait spectrum (leaf nitrogen, N_Leaf, and specific leaf area, SLA). For both, species in the resident communities and the phytometers, we tested whether their assignment as winner or losers can be explained by their leaf economics.
In the resident communities, plot-specific winners had a greater SLA than losers, but only in high-diversity mixtures and especially in those with an older history, while the relationships to N_Leaf varied with community history. In the phytometer experiment, plant individual biomass, formation of flowers, and N_Leaf of phytometers decreased, while SLA increased with plant species richness in both history treatments. Phytometer survival and N_Leaf were higher in the new communities. In the mixtures, and especially in those with new soil, winner phytometers had higher N_Leaf than expected from the monocultures, but did not differ in their performance or other traits from loser ones. In the monocultures, winner phytometers had higher SLA than loser ones.
Synthesis. Our results suggest that fast-growing, high-nutrient demanding species are winners in high-diversity mixtures, which can be well predicted from their SLA. However, our results regarding N_Leaf suggest that the predictability of species performances changes with age of the experimental communities and that presumably more complex plant–soil interactions in older communities impede simple growth trait-related explanations.

Details are in the caption following the image — Summary of the experimental design, including analysis of long-term data of the biodiversity experiment with 66 plant mixtures of varying species richness (2, 4, 8, 16 and 60 species) assembled from a pool of 60 plant species and their monocultures. (a) Time series data were used to identify plot-specific ‘winners’ (high-performing, overyielding species; visualized with red colour) and ‘losers’ (low-performing, underyielding species; visualized with blue colour). (b) Two ‘loser’ and two ‘winner’ species of each mixture were planted as phytometers in subplots with ‘new communities’ on new soil and in ‘old communities’ and their respective monocultures. Trait data measured at the phytometers were used to test for trait differences between winners and losers. Created in BioRender. Roscher, C. (2025) https://BioRender.com/umzkvp8.

Reference:

Roscher, C., Y. Feng, and N. Eisenhauer. 2025. Plant species with ‘fast’ traits are winners in young and high-diversity plant communities. Journal of Ecology. e70216. https://doi.org/10.1111/1365-2745.70216