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Impacts of climate change on hydrological ecosystems functions in Mesoamerica

Imbach P., Locatelli B., Molina L.G.. 2008. In : Adaptation of forests and forest management to changing climate with emphasis on forest health : a review of science, policies and practices. Book of abstracts and preliminary programme. Uppsala : Swedish University of Agricultural Sciences, p. 100-100. International Conference on Adaptation of Forests and Forest Management to Changing Climate with Emphasis on Forest Health. 13, 2008-08-25/2008-08-28, Umea (Suède).

Terrestrial ecosystems provide an array of hydrological functions important for human well-being. Hydrological regimes will be affected by climate change with impacts on the distribution of ecosystems and the pattern and variability of precipitation and temperature. We aim at evaluating the impacts of climate change on forest ecosystems hydrological functions in Mesoamerica. For this purpose, we calibrated and validated the Mapped Atmosphere Plant Soil System (MAPSS), a static soil-vegetation-atmosphere (SVAT) model, to map potential changes on vegetation parameters relevant for the water balance and runoff patterns and under future climatic scenarios. MAPSS operates on the fundamental principle that ecosystems will tend to maximize the leaf area that can be supported at a site by available soil moisture or energy, and therefore simulates potential vegetation. The model calculates the leaf area index (LAI) of both woody and grass life forms in competition for both light and water, while maintaining a site water balance. Model validation was made with LAI product (MODI5A2) from Collection 5 of MODIS Terra sensor, and runoff data from selected watersheds in the region. The validation step is crucial for creating confidence in the model to simulate future scenarios. Results show how climate change will affect the distribution of life forms, its leaf area density as well as runoff patters across a tropical region. This study sets the basis for further analysis of the impacts of climate change on ecosystems and water availability. (Texte intégral)

Mots-clés : amérique centrale

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