Erratum: correction: Plant diversity enhances ecosystem responses to elevated CO2 and nitrogen deposition

Abstract

Human actions are causing declines in plant biodiversity, increases in atmospheric CO 2 concentrations and increases in nitrogen deposition; however, the interactive effects of these factors on ecosystem processes are unknown 1,2 . Reduced biodiversity has raised numerous concerns, including the possibility that ecosystem functioning may be affected negatively 1±4 , which might be particularly important in the face of other global changes 5,6 . Here we present results of a grassland ®eld experiment in Minnesota, USA, that tests the hypothesis that plant diversity and composition in¯uence the enhancement of biomass and carbon acquisition in ecosystems subjected to elevated atmospheric CO2 concentrations and nitrogen deposition. The study experimentally controlled plant diversity (1, 4, 9 or 16 species), soil nitrogen (unamended versus deposition of 4 g of nitrogen per m 2 per yr) and atmospheric CO2 concentrations using freeair CO2 enrichment (ambient, 368mmol mol -1 , versus elevated, 560mmol mol -1 ). We found that the enhanced biomass accumulation in response to elevated levels of CO 2 or nitrogen, or their combination, is less in species-poor than in species-rich assemblages.