Linking traits of foraging animals to spatial patterns of plants: social and solitary ants generate opposing patterns of surviving seeds

Authors

  • Tal Avgar,

    Corresponding author
    1. The Movement Ecology Laboratory, Department of Evolution, Systematics and Ecology, Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
      *E-mail: tal.avgar@mail.huji.ac.il
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  • Itamar Giladi,

    1. Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus, Midreshet Ben Gurion 84990, Israel
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  • Ran Nathan

    1. The Movement Ecology Laboratory, Department of Evolution, Systematics and Ecology, Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
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*E-mail: tal.avgar@mail.huji.ac.il

Abstract

Foraging traits of seed predators are expected to impact the spatial structure of plant populations, community dynamics and diversity. Yet, many of the key mechanisms governing distance- or density-dependent seed predation are poorly understood. We designed an extensive set of field experiments to test how seed predation by two harvester ant species interact with seed dispersal in shaping the spatial patterns of surviving seeds. We show that the Janzen–Connell establishment pattern can be generated by central-place foragers even if their focal point is located away from the seed source. Furthermore, we found that differences in the social behaviour of seed predators influence their sensitivity to seed density gradients and yield opposing spatial patterns of surviving seeds. Our results support the predictions of a recent theoretical framework that unifies apparently opposing plant establishment patterns, and suggest that differences in foraging traits among seed predators can drive divergent pathways of plant community dynamics.

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