The effects of biodiversity on ecosystem functioning generally increase over time, but the underlying processes remain unclear. Using 26 long-term grassland and forest experimental ecosystems, we demonstrate that biodiversity–ecosystem functioning relationships strengthen mainly by greater increases in functioning in high-diversity communities in grasslands and forests. In grasslands, biodiversity effects also strengthen due to decreases in functioning in low-diversity communities. Contrasting trends across grasslands are associated with differences in soil characteristics.
This study was supported by the German Research Foundation through the Emmy Noether research group (Ei 862/2), a European Research Council starting grant (grant agreement 677232) provided to N.E. and financial support from the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig (FZT 118). The Jena Experiment is funded by the Deutsche Forschungsgemeinschaft (FOR 1451). Support for BioCON came from the US National Science Foundation (NSF) Long-Term Ecological Research (DEB-9411972, DEB-0080382, DEB-0620652 and DEB-1234162), Biocomplexity Coupled Biogeochemical Cycles (DEB-0322057), Long-Term Research in Environmental Biology (DEB-0716587, DEB-1242531) and Ecosystem Sciences (NSF DEB- 1120064) Programs; as well as the US Department of Energy Programs for Ecosystem Research (DE-FG02-96ER62291) and National Institute for Climatic Change Research (DE-FC02-06ER64158). N.R.G.-R. thanks D. Binkley, A. Weigelt and E. De Luca for contributing data, S. Bilodeau-Gauthier for support with the database and P. Keil for help with data analysis.
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