Contrasting trait responses in plant communities to experimental and geographic variation in precipitation

Authors

  • Brody Sandel,

    1. Department of Integrative Biology, University of California, Berkeley, 3060 VLSB #3140, Berkeley, CA 94720, USA
    2. Department of Biological Science, The Ecoinformatics and Biodiversity Group, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark
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  • Leah J. Goldstein,

    1. Department of Ecology and Evolutionary Biology, 321 Steinhaus Hall, University of California, Irvine, Irvine, CA 92697-2525, USA
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  • Nathan J.B. Kraft,

    1. Department of Integrative Biology, University of California, Berkeley, 3060 VLSB #3140, Berkeley, CA 94720, USA
    2. Biodiversity Research Centre, University of British Columbia, 6270 University Blvd., Vancouver, BC V6t 1Z4, Canada
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  • Jordan G. Okie,

    1. Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
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  • Michal I. Shuldman,

    1. Department of Integrative Biology, University of California, Berkeley, 3060 VLSB #3140, Berkeley, CA 94720, USA
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  • David D. Ackerly,

    1. Department of Integrative Biology, University of California, Berkeley, 3060 VLSB #3140, Berkeley, CA 94720, USA
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  • Elsa E. Cleland,

    1. Ecology, Behavior & Evolution Section, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
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  • Katharine N. Suding

    1. Department of Environmental Science, Policy and Management, University of California, Berkeley, 137 Mulford Hall #3114, Berkeley, CA 94720, USA
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Author for correspondence:
Brody Sandel
Tel: +1 (510) 643 5782
Email: brody.sandel@biology.au.dk

Summary

  • Patterns of precipitation are likely to change significantly in the coming century, with important but poorly understood consequences for plant communities. Experimental and correlative studies may provide insight into expected changes, but little research has addressed the degree of concordance between these approaches.
  • We synthesized results from four experimental water addition studies with a correlative analysis of community changes across a large natural precipitation gradient in the United States. We investigated whether community composition, summarized with plant functional traits, responded similarly to increasing precipitation among studies and sites.
  • In field experiments, increased precipitation favored species with small seed size, short leaf life span and high leaf nitrogen (N) concentration. However, with increasing precipitation along the natural gradient, community composition shifted towards species with higher mean seed mass, longer leaf life span and lower leaf N concentrations.
  • The differences in temporal and spatial scale of experimental manipulations and natural gradients may explain these contrasting results. Our results highlight the complexity of responses to climate change, and suggest that transient dynamics may not reflect long-term shifts in functional diversity and community composition. We propose a model of community change that incorporates these differences between short- and long-term responses to climate change.

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