Species divergence and trait convergence in experimental plant community assembly

Authors

  • Tadashi Fukami,

    Corresponding author
    1. Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, PO Box 40, 6666 ZG Heteren, The Netherlands
    2. Landcare Research, PO Box 69, Lincoln, New Zealand
    3. Laboratory of Biodiversity Science, School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan
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  • T. Martijn Bezemer,

    1. Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, PO Box 40, 6666 ZG Heteren, The Netherlands
    2. Laboratory of Entomology, Wageningen University and Research Centre, PO Box 8031, 6700 ES Wageningen, The Netherlands
    3. Laboratory of Nematology, Wageningen University and Research Centre, PO Box 8123, 6700 ES Wageningen, The Netherlands
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  • Simon R. Mortimer,

    1. Department of Agriculture, Centre for Agri-Environmental Research, University of Reading, PO Box 237, Reading RG6 6AR, UK
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  • Wim H. van der Putten

    1. Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, PO Box 40, 6666 ZG Heteren, The Netherlands
    2. Laboratory of Nematology, Wageningen University and Research Centre, PO Box 8123, 6700 ES Wageningen, The Netherlands
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* E-mail: fukamit@landcareresearch.co.nz

Abstract

Despite decades of research, it remains controversial whether ecological communities converge towards a common structure determined by environmental conditions irrespective of assembly history. Here, we show experimentally that the answer depends on the level of community organization considered. In a 9-year grassland experiment, we manipulated initial plant composition on abandoned arable land and subsequently allowed natural colonization. Initial compositional variation caused plant communities to remain divergent in species identities, even though these same communities converged strongly in species traits. This contrast between species divergence and trait convergence could not be explained by dispersal limitation or community neutrality alone. Our results show that the simultaneous operation of trait-based assembly rules and species-level priority effects drives community assembly, making it both deterministic and historically contingent, but at different levels of community organization.

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