Biotic controls on shallow translational landslides

Authors

  • Peter Vorpahl,

    Corresponding author
    1. Technische Universität München, Landscape Ecology, Freising-Weihenstephan, Germany
    • University of Potsdam, Institute of Earth and Environmental Sciences, Potsdam, Germany
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  • Claudia Dislich,

    1. Helmholtz Centre for Environmental Research – UFZ, Department of Ecological Modelling, Leipzig, Germany
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  • Helmut Elsenbeer,

    1. University of Potsdam, Institute of Earth and Environmental Sciences, Potsdam, Germany
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  • Michael Märker,

    1. Heidelberger Akademie der Wissenschaften, c/o Geographisches Institut der Eberhard Karls Universität, Tübingen, Germany
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  • Boris Schröder

    1. University of Potsdam, Institute of Earth and Environmental Sciences, Potsdam, Germany
    2. Technische Universität München, Landscape Ecology, Freising-Weihenstephan, Germany
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Correspondence to: Peter Vorpahl, University of Potsdam, Institute of Earth and Environmental Sciences, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany. E-mail: peter.vorpahl@uni-potsdam.de

ABSTRACT

In undisturbed tropical montane rainforests massive organic layers accommodate the majority of roots and only a small fraction of roots penetrate the mineral soil. We investigated the contribution of vegetation to slope stability in such environments by modifying a standard model for slope stability to include an organic layer with distinct mechanical properties. The importance of individual model parameters was evaluated using detailed measurements of soil and vegetation properties to reproduce the observed depth of 11 shallow landslides in the Andes of southern Ecuador. By distinguishing mineral soil, organic layer and above-ground biomass, it is shown that in this environment vegetation provides a destabilizing effect mainly due to its contribution to the mass of the organic layer (up to 973 t ha− 1 under wet conditions). Sensitivity analysis shows that the destabilizing effect of the mass of soil and vegetation can only be effective on slopes steeper than 37.9°. This situation applies to 36% of the study area. Thus, on the steep slopes of this megadiverse ecosystem, the mass of the growing forest promotes landsliding, which in turn promotes a new cycle of succession. This feedback mechanism is worth consideration in further investigations of the impact of landslides on plant diversity in similar environments. Copyright © 2012 John Wiley & Sons, Ltd.

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