Mechanisms of positive biodiversity-production relationships:: insights provided by δ13C analysis in experimental Mediterranean grassland plots

We investigated the role of water use in a Mediterranean grassland, in which diversity was experimentally manipulated, and a positive relationship was observed between plant species richness and productivity. Soil moisture patterns and stable carbon isotope ratios (PC) in leaves indicated greater water use by plants growing in species-rich mixtures compared to monocultures. These results suggest that complementarity or facilitation may be the mechanism responsible for the positive relationship between plant diversity and ecosystem processes.