Ecological, historical and evolutionary determinants of modularity in weighted seed-dispersal networks

Authors

  • Matthias Schleuning,

    Corresponding author
    1. Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt am Main, Germany
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  • Lili Ingmann,

    1. Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt am Main, Germany
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  • Rouven Strauß,

    1. Department of Computer Science, Technion – Israel Institute of Technology, Haifa, Israel
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  • Susanne A. Fritz,

    1. Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt am Main, Germany
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  • Bo Dalsgaard,

    1. Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Copenhagen Ø, Denmark
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  • D. Matthias Dehling,

    1. Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt am Main, Germany
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  • Michaela Plein,

    1. Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt am Main, Germany
    2. School of Botany, The University of Melbourne, Parkville, VIC, Australia
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  • Francisco Saavedra,

    1. Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt am Main, Germany
    2. Institute for Biology/Geobotany and Botanical Garden, Martin-Luther-University, Halle-Wittenberg, Halle (Saale), Germany
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  • Brody Sandel,

    1. Ecoinformatics and Biodiversity, Department of Bioscience, Aarhus University, Aarhus C, Denmark
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  • Jens-Christian Svenning,

    1. Ecoinformatics and Biodiversity, Department of Bioscience, Aarhus University, Aarhus C, Denmark
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  • Katrin Böhning-Gaese,

    1. Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt am Main, Germany
    2. Department of Biological Sciences, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt (Main), Germany
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  • Carsten F. Dormann

    1. Biometry and Environmental System Analysis, University of Freiburg, Freiburg, Germany
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Abstract

Modularity is a recurrent and important property of bipartite ecological networks. Although well-resolved ecological networks describe interaction frequencies between species pairs, modularity of bipartite networks has been analysed only on the basis of binary presence–absence data. We employ a new algorithm to detect modularity in weighted bipartite networks in a global analysis of avian seed-dispersal networks. We define roles of species, such as connector values, for weighted and binary networks and associate them with avian species traits and phylogeny. The weighted, but not binary, analysis identified a positive relationship between climatic seasonality and modularity, whereas past climate stability and phylogenetic signal were only weakly related to modularity. Connector values were associated with foraging behaviour and were phylogenetically conserved. The weighted modularity analysis demonstrates the dominating impact of ecological factors on the structure of seed-dispersal networks, but also underscores the relevance of evolutionary history in shaping species roles in ecological communities.

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