Clonal traits outperform foliar traits as predictors of ecosystem function in experimental mesocosms

International audienceQuestions: Is productivity linked with clonal traits through their indirect effect on competitive interactions? Are clonal traits better predictors of productivity than foliar traits? Location: Rennes, France. Methods: We used a wide-scale mesocosm experiment based on several assemblages of species differing in clonal traits, and evaluated if the relationship between biomass production and clonal traits is consistent at different ecological scales. Results: Results showed that at the individual level, foliar traits were independent from clonal traits in most studied species. Community specific above-ground net primary productivity was significantly correlated to community-aggregated values of clonal and foliar traits. Nevertheless, a stronger relationship with clonal traits was indicated, emphasizing a plant foraging strategy along the horizontal plant plane, which was a determinant of community productivity. An inverse relationship between clonal traits and biomass production was observed at the individual and community levels, which was attributed to modifications in resource acquisition processes resulting from competitive interactions. Conclusions:We demonstrated that clonal traits are correlated with productivity at the individual and community scales. These traits were indicators of resource acquisition processesmediated through competitive interactions