The ecology of differences: assessing community assembly with trait and evolutionary distances

Authors

  • Marc Cadotte,

    Corresponding author
    1. Department of Biological Sciences, University of Toronto - Scarborough, Toronto, ON, Canada
    2. Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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    • All authors contributed equally to the writing of this article.
  • Cecile H. Albert,

    1. Laboratoire d'Ecologie Alpine, UMR CNRS 5553, CNRS, Universite Joseph Fourier, Grenoble Cedex 9, France
    2. Department of Biology, McGill University, Montreal, QC, Canada
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    • All authors contributed equally to the writing of this article.
  • Steve C. Walker

    1. Departement de Sciences Biologiques, Universite de Montreal, Montreal, QC, Canada
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    • All authors contributed equally to the writing of this article.

Abstract

Species enter and persist in local communities because of their ecological fit to local conditions, and recently, ecologists have moved from measuring diversity as species richness and evenness, to using measures that reflect species ecological differences. There are two principal approaches for quantifying species ecological differences: functional (trait-based) and phylogenetic pairwise distances between species. Both approaches have produced new ecological insights, yet at the same time methodological issues and assumptions limit them. Traits and phylogeny may provide different, and perhaps complementary, information about species' differences. To adequately test assembly hypotheses, a framework integrating the information provided by traits and phylogenies is required. We propose an intuitive measure for combining functional and phylogenetic pairwise distances, which provides a useful way to assess how functional and phylogenetic distances contribute to understanding patterns of community assembly. Here, we show that both traits and phylogeny inform community assembly patterns in alpine plant communities across an elevation gradient, because they represent complementary information. Differences in historical selection pressures have produced variation in the strength of the trait-phylogeny correlation, and as such, integrating traits and phylogeny can enhance the ability to detect assembly patterns across habitats or environmental gradients.

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