A novel proxy to examine interspecific phosphorus facilitation between plant species

<p>Resource complementarity can contribute to enhanced ecosystem functioning in diverse plant communities, but the role of facilitation in the enhanced complementarity is poorly understood.</p> <p>Here, we use leaf manganese concentration ([Mn]) as a proxy for rhizosheath carboxylate concentration to explore novel mechanisms of complementarity mediated by phosphorus (P) facilitation.</p> <p>In pot experiments, we showed that mixtures involving <em>Carex korshinskyi</em>, an efficient P-mobilizing species, exhibited greater biomass and relative complementarity effect than combinations without <em>C. korshinskyi </em>on P-deficient soils. Compared with monocultures, leaf [Mn] and [P] of species that are inefficient at P mobilization increased by 27 and 21% when grown with <em>C. korshinskyi</em> (i.e. interspecific P facilitation via carboxylates) rather than next to another inefficient P-mobilizing species. This experimental result was supported by a meta-analysis including a range of efficient P-mobilizing species. Phosphorus facilitation enhanced the relative complementarity effect in low-P environments, related to a greater change in several facilitated species of their root morphological traits relative to those in monoculture.</p> <p>Using leaf [Mn] as a proxy, we highlight a vital mechanism of interspecific P facilitation via belowground processes and provide evidence for the pivotal role of P facilitation mediated by the plasticity of root traits in biodiversity research.</p>