Inducible defences prevent strong population fluctuations in bi- and tritrophic food chains

Authors

  • Antonie M. Verschoor,

    Corresponding author
    1. Department of Food Web Studies, Netherlands Institute of Ecology (NIOO-KNAW), Centre for Limnology, Rijksstraatweg 6, 3631 AC Nieuwersluis, The Netherlands
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  • Matthijs Vos,

    1. Department of Food Web Studies, Netherlands Institute of Ecology (NIOO-KNAW), Centre for Limnology, Rijksstraatweg 6, 3631 AC Nieuwersluis, The Netherlands
    2. Department of Multitrophic Interactions, Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, Boterhoeksestraat 48, 6666 GA Heteren, The Netherlands
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  • Irene Van Der Stap

    1. Department of Food Web Studies, Netherlands Institute of Ecology (NIOO-KNAW), Centre for Limnology, Rijksstraatweg 6, 3631 AC Nieuwersluis, The Netherlands
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* E-mail: a.verschoor@nioo.knaw.nl

Abstract

Recent theoretical work (Vos et al. 2004) predicts that inducible defences prevent strong population fluctuations under high levels of nutrient enrichment. Here we evaluate this model prediction and show that inducible defences in algae stabilize the dynamics of experimentally assembled bi- and tritrophic planktonic food chains. At high phosphorus levels, we observed strong population fluctuations in all food chains with undefended algae. These fluctuations did not occur when algae had inducible defences. At low phosphorus levels, we observed deterministic consumer extinctions, as predicted by stoichiometric theory. Our study thus shows that both biotically and abiotically induced changes in algal food quality affect the stability and persistence of planktonic food chains.

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