Hydrological consequences of Eucalyptus afforestation in the Argentine Pampas

Authors

  • Vic Engel,

    1. National Park Service, Everglades National Park, Homestead, Florida, USA
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  • Esteban G. Jobbágy,

    1. Grupo de Estudios Ambientales, Instituto de Matemática Aplicada San Luis, Universidad de Nacional de San Luis, San Luis, Argentina
    2. Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto Nacional de Tecnologia Agropecuaria San Luis, San Luis, Argentina
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  • Marc Stieglitz,

    1. School of Civil and Environmental Engineering and School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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  • Mathew Williams,

    1. Institute of Atmospheric and Environmental Sciences, University of Edinburgh, Edinburgh, UK
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  • Robert B. Jackson

    1. Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto Nacional de Tecnologia Agropecuaria San Luis, San Luis, Argentina
    2. Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina, USA
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Abstract

[1] The impacts of a 40 ha stand of Eucalyptus camaldulensis in the Pampas grasslands of Argentina were explored for 2 years using a novel combination of sap flow, groundwater data, soil moisture measurements, and modeling. Sap flow measurements showed transpiration rates of 2–3.7 mm d−1, lowering groundwater levels by more than 0.5 m with respect to the surrounding grassland. This hydraulic gradient induced flow from the grassland areas into the plantation and resulted in a rising of the plantation water table at night. Groundwater use estimated from diurnal water table fluctuations correlated well with sap flow (p < 0.001, r2 = 0.78). Differences between daily sap flow and the estimates of groundwater use were proportional to changes in surface soil moisture content (p < 0.001, r2 = 0.75). E. camaldulensis therefore used both groundwater and vadose zone moisture sources, depending on soil water availability. Model results suggest that groundwater sources represented ∼67% of total annual water use.

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