Ecohydrological Source-Sink Interrelationships between Vegetation Patches and Soil Hydrological Properties along a Disturbance Gradient Reveal a Restoration Threshold

Authors

  • Luis Merino-Martín,

    Corresponding author
    1. Departamento de Ecología, Universidad de Alcalá, Alcalá de Henares, Madrid, E-28871, España
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  • David D. Breshears,

    1. School of Natural Resources and the Environment, The University of Arizona, Tucson, AZ, U.S.A.
    2. Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, AZ, U.S.A.
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  • Mariano Moreno-de las Heras,

    1. Faculty of Engineering and Built Environment, The University of Newcastle, Callaghan, NSW 2308, Australia
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  • Juan Camilo Villegas,

    1. School of Natural Resources and the Environment, The University of Arizona, Tucson, AZ, U.S.A.
    2. Grupo GIGA, Facultad de Ingeniería, Universidad de Antioquia, Medellín, Colombia
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  • Silvia Pérez-Domingo,

    1. Departamento de Ecología, Universidad de Alcalá, Alcalá de Henares, Madrid, E-28871, España
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  • Tíscar Espigares,

    1. Departamento de Ecología, Universidad de Alcalá, Alcalá de Henares, Madrid, E-28871, España
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  • Jose M. Nicolau

    1. Departamento de Agricultura y Economía Agraria, Escuela Politécnica, Universidad de Zaragoza, Huesca, España
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L. Merino-Martin, email luis.merino@uah.es

Abstract

Vegetation, soil, and hydrology in drylands often collectively exhibit strong ecohydrological interrelationships in which vegetation both influences and is influenced by runoff, particularly on sites with more gradual slopes. These two-way relationships have important implications for ecological restoration of disturbed sites, such as those being reclaimed following mining, yet studies from both ecological and hydrological perspectives specifically evaluating how the strength of ecohydrological interrelationships varies for a range of natural and restored conditions are still missing. We assessed two-way relationships between vegetation and soil hydrological properties by evaluating patterns of both plant community structure and soil hydrological characteristics related to runoff for natural sites and restored sites following mining. At the plot scale, we identified eight ecohydrological units based on interrelationships between vegetation communities and hydrological properties associated with runoff along a progression from source to sink patch types. Similarly, at the hillslope scale, which included patches of different types, we found a correspondence between the proportions of source and sink patches and both vegetation community and hydrological properties. The relative strength of ecohydrological interrelationships in hillslope mosaics decreased with decreasing disturbance except for rilled hillslopes, likely because parts of the hillslope become isolated from the others. Our results highlight, in general, how ecohydrological interrelationships are related with degree of disturbance, and in particular, how rilling alters ecohydrological interrelationships, thereby precluding effective restoration.

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