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Microscale vegetation-soil feedback boosts hysteresis in a regional vegetation–climate system

Authors

  • RUUD H. H. JANSSEN,

    1. Earth System Science-Climate Change, Wageningen University and Research Centre, PO Box 47, 6700 AA Wageningen, The Netherlands,
    2. Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands,
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  • MARCEL B. J. MEINDERS,

    1. Earth System Science-Climate Change, Wageningen University and Research Centre, PO Box 47, 6700 AA Wageningen, The Netherlands,
    2. Agrotechnology & Food Innovation, Wageningen University and Research Centre, PO Box 17, 3700 AA Wageningen, The Netherlands,
    3. T. I. Food and Nutrition, PO Box 557, 6700 AN Wageningen, The Netherlands
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  • EGBERT H. Van NES,

    1. Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands,
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  • MARTEN SCHEFFER

    1. Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands,
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Egbert H. van Nes, tel. +31 317 482733, fax +31 317 484411, e-mail: egbert.vannes@wur.nl

Abstract

It has been hypothesized that a positive feedback between vegetation cover and monsoon circulation may lead to the existence of two alternative stable states in the Sahara region: a vegetated state with moderate precipitation and a desert state with low precipitation. This could explain the sudden onset of desertification in the region about 5000 years ago. However, other models suggest that the effect of vegetation on the precipitation may be insufficient to produce this behavior. Here, we show that inclusion of the microscale feedback between soil and vegetation in the model greatly amplifies the nonlinearity, causing alternative stable states and considerable hysteresis even if the effect of vegetation on precipitation is moderate. On the other hand, our analysis suggests that self-organized vegetation patterns known from models that only focus at the microscale plant–soil feedback will be limited to a narrower range of conditions due to the regional scale climate-feedback. This implies that in monsoon areas such as the Western Sahara self-organized vegetation patterns are predicted to be less common than in areas without monsoon circulation such as Central Australia.

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