Changes in diatom patch-size distribution and degradation in a spatially self-organized intertidal mudflat ecosystem

Authors

  • E. J. Weerman,

    Corresponding author
    1. Centre for Estuarine and Marine Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 40, 4400 AC Yerseke, The Netherlands
    2. Aquatic Ecology and Ecotoxicology (IBED), University of Amsterdam, P.O. Box 94240, 1090 GE Amsterdam, The Netherlands
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  • J. Van Belzen,

    1. Centre for Estuarine and Marine Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 40, 4400 AC Yerseke, The Netherlands
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  • M. Rietkerk,

    1. Department of Environmental Sciences, Utrecht University, P.O. Box 80115, 3508 TC Utrecht, The Netherlands
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  • S. Temmerman,

    1. University of Antwerpen, Department of Biology, Universiteitsplein 1, 2610 Wilrijk, Belgium
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  • S. Kéfi,

    1. Institut des Sciences de l'Evolution, CNRS UMR 5554, Bat 22, second floor, Université de Montpellier II, CC 065, 34095 Montpellier Cedex 05, France
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  • P. M. J. Herman,

    1. Centre for Estuarine and Marine Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 40, 4400 AC Yerseke, The Netherlands
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  • J. Van de Koppel

    1. Centre for Estuarine and Marine Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 40, 4400 AC Yerseke, The Netherlands
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  • Corresponding Editor: J. J. Stachowicz.

Abstract

Self-organized spatial patterns have been proposed as possible indicators for regime shifts in ecosystems. Until now, this hypothesis has only been tested in drylands. Here, we focus on intertidal mudflats where regular spatial patterns develop in early spring from the interaction between diatom growth and sedimentation but disappear when benthic herbivore abundance increases in early summer, accompanied by a dramatic shift to a bare mudflat. We followed the patch-size distributions of diatom biofilms during this degradation process. As time progressed, we found a temporal change in the spatial configuration occurring simultaneously with the loss of the diatom–sediment feedback. This indicates a gradual failure in time of the self-organization process that underlies regular patterning in this ecosystem. The path to degradation co-occurred with the loss of the larger patches in the ecosystem, which resulted in a decrease of the truncation in the patch-size distribution. Hence, our study in mudflat ecosystems confirms the general hypothesis that spatial patterns can provide important clues about the level of degradation. Nevertheless, our study highlights the need for thorough study about the type of spatial patterns and the nature of the underlying feedbacks before a reliable assessment of ecosystem status can be made, as changes in patch-size distribution differed markedly with those observed in other ecosystems.

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