Linking patterns in phylogeny, traits, abiotic variables and space: a novel approach to linking environmental filtering and plant community assembly

Authors

  • Sandrine Pavoine,

    Corresponding author
    1. Mathematical Ecology Research Group, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
    2. Muséum national d’Histoire naturelle, Département Ecologie et Gestion de la Biodiversité, UMR 7204 MNHN-CNRS-UPMC, 61 rue Buffon, 75005 Paris, France
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  • Errol Vela,

    1. Université Montpellier 2, UMR AMAP, TA A51/PS2, 34398 Montpellier Cedex 5, France
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  • Sophie Gachet,

    1. Institut Méditerranéen d’Ecologie et de Paléoécologie, UMR CNRS-IRD 6116, Université Paul Cézanne, 13397 Marseille Cedex 20, France
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  • Gérard de Bélair,

    1. B.P. 533, 23000 Annaba, Algeria
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  • Michael B. Bonsall

    1. Mathematical Ecology Research Group, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
    2. St. Peter’s College, Oxford OX1 2DL, UK
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Correspondence author. E-mail: pavoine@mnhn.fr

Summary

1. We introduce a novel method that analyses environmental filtering of plant species in a geographic and phylogenetic context. By connecting species traits with phylogeny, traits with environment, and environment with geography, this comprehensive approach partitions the ecological and evolutionary processes that influence community assembly.

2. Our analysis extends RLQ ordination, which connects site attributes in matrix R (here environmental variables and spatial positions) with species attributes in matrix Q (here biological traits and phylogenetic positions), through the composition of sites in terms of species presences or abundances (matrix L). This methodology, which explores and identifies environmental filters that organize communities, was developed to answer four questions: which combinations of trait states are filtered by the environment, which lineages are affected by these filters, which environmental variables contribute to the assemblage of local communities and where do these filters act?

3. At La Mafragh in north-eastern Algeria, our approach shows that plant species traits were distributed according to environmental filters associated with a salinity gradient. Traits associated with the salinity gradient were convergent among Juncaceae, Cyperaceae and Amaranthaceae. The observed phylogenetic and trait patterns were related to how species survived the xeric season. Juncaceae and Cyperaceae, being perennials and anemogamous, tolerate the xeric hot season by restricting their range to the humid centre of the study area (where conditions are close to a subtropical climate). Several Amaranthaceae species co-occur with the Juncaceae and Cyperaceae in two areas with the highest salinity. Most dicots were observed at higher elevations (up to 7 m a.s.l.), had hairy structures that can retain water and reflect solar radiation and were mostly annual or biennial, completing their life cycle before the onset of the xeric season.

4.Synthesis. Our methodology describes environmental filters in terms of identified combinations of traits and environmental factors. It allows spatial and phylogenetic signals to be determined by identifying convergent and conserved patterns in the evolution of traits and spatial scales that structured the environment. Our statistical framework is generic and can be readily extended to a wide range of exciting issues, such as host-parasite, plant-pollinator and predator–prey interactions.

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