Ecohydrological process studies and model development to evaluate the impact of land-use change and vegetation dynamics on the hydrological cycle and the biogeochemical cycling
Zusammenfassung der Projektergebnisse
The aim of the ECHO project was to evaluate the impacts of land-use change of agricultural fields on the ecohydrological functioning, interactions and transfer processes resulting in water and soil degradation within meso-scale catchments. Thematic emphasis was placed on the ecohydrological aspects of land-use change and land degradation of three very different landscape systems, which have been studied in regard to their underlying ecohydrological controls and processes after being subjected to man-made land-use change which has led to either ecosystem stabilisation or ecosystem degradation: 1) in the south-western part of the United States (New Mexico), a significant vegetation change from productive grassland to shrubland accompanied with severe land degradation and desertification occurred within the past 150 years due to excessive overgrazing and 2) the Cerrado biome in central-western part of Brazil has experienced a rapid land-use change from natural forest savannah to croplands and pastures in South America over the last 30 years and has lost half of the original extent of 2 million square kilometres for agricultural land-use and 3) the temperature agricultural area of Brandenburg in central-eastern Germany which after a period of extensification in the 1990s has experienced an increase of agricultural activities over the last decade. Methodological emphasis was placed on the development of numerical, (semi)-process-based models for simulation of vegetation, water and sediment dynamics from the hillslope to mesoscale that either implicitly include feedbacks between ecological and hydrological state variables or work with a model cascade approach to reproduce intrinsic ecohydrological interactions. For the feedback modelling approach, an ecohydrological, process-based model, Mahleran-EcoHyD, was developed to further the understanding of the complex linkages between abiotic and biotic drivers and processes of degradation in drylands. The coupled model was used to investigate soil-vegetation-transfer feedback mechanisms within grassland-shrubland transition zones in the Chihuahuan shrub desert by modelling the ecohydrological feedbacks caused by different vegetation dynamic scenarios. Cascade modelling approaches were employed to study water and land degradation in the Cerrado ecosystem; the ecosystem degradation state was priory quantified with integrated field studies (looking at both water and soil degradation) and a thorough meta-analysis of existing soil, ecological and water quality research studies to assess the effects of land-use change from natural Cerrado to cropland on water and land resources. Comparing both modelling approaches, ecohydrological models with feedbacks can be used for hypothesis testing at the hillslope scale, but they appear to be too time-consuming in regard to computing time to be employed at the meso-scale. Cascade models work better at the mesoscale to assess both the management of land-use and the impacts of climate change scenarios, but there is the danger that they dysfunction by neglecting some critical interactions of soilwater-vegetation processes at the hillslope scale. Land-use change was studied as a nonlinear, multi-disciplinary process which required an equally complex, interdisciplinary approach to monitor, model and analyse. Ecohydrology as a science field includes both flora and fauna, but disregards in its modelling and monitoring schemes the humans as normally very (inter)active members of an ecosystem. For a really integrated approach of water and soil management we will need to go beyond mere ecohydrology, but need to include the human dimension into our research framework. One innovative way of achieving an integrated water and soil management could be the dynamic linking of process-based ecohydrological models to the functioning of the public domain such as water and land users, farmers, stakeholders and policy makers from institutions and environmental protection agencies. To pursue these research challenges, I was granted funding for a DFG Heisenberg professorship on Ecohydrology and Landscape Analysis at the Department of Ecology, TU Berlin.
Projektbezogene Publikationen (Auswahl)
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(2009) Modelling the effects of land-use change on runoff and sediment yield for a meso-scale catchment in the Southern Pyrenees, CATENA 79: 103-111
Mueller, EN., RJ. Batalla, T. Francke, A. Bronstert
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(2009) Response to Kinnell’s ‚Comment on „A transport-distance approach to scaling erosion rates: III. Evaluating scaling characteristics of Mahleran”’, Earth Surface Processes and Landforms
Wainwright, J., Parsons, A.J., Müller, EN., Brazier, R.E., Powell, D.M.
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(2010) Standing proud: a response to ‘Soil-ersoion models: where do we really stand?’ by Smith et al., Earth Surface Processes and Landforms
Wainwright, J., Parsons, AJ., Müller, EN., Brazier, R.E., Powell, D.M.
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(2010): Modelling water availability, sediment export and reservoir sedimentation in drylands with the WASA-SED model. Geosci. Model Dev., 3, 275-291
Mueller, EN., Güntner, A., Francke, T., Mamede, G.
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(2011) Increasing occurrence of high-intensity rainstorm events relevant for the generation of soil erosion in a temperate lowland region in Central Europe, Journal of Hydrology 411: 266-278
Mueller, EN., Pfister, A.
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(2013) Comparing impacts of climate change on streamflow in four large African river basins. Hydrology and Earth System Sciences Discussions 10 (11), 13005-13052
Aich V, S Liersch, T Vetter, S Huang, J Tecklenburg, P Hoffmann, H Koch, V Krysanova, E N Mueller, F Hattermann
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(2014) Comparing impacts of climate change on streamflow in four large African river basins. Hydrology and Earth System Sciences
Aich, V., Liersch, S., Vetter, T., Huang, S., Tecklenburg, J., Hoffmann, P., Koch, H., Fournet, S., Krysanova, V., Müller, E. N. and F. F. Hattermann
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(2014) Patterns of land degradation in drylands: Understanding self-organized ecogeomorphic systems. Springer, Utrecht, 395 p.
Mueller, EN. J. Wainwright, L. Turnbull, A.J. Parsons
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(2014) Skalen, Schwerpunkte, Rückkopplungen und Herausforderungen der ökohydrologischen Forschung in Deutschland. Hydrologie und Wasserbewirtschaftung
Müller, Eva Nora, Loes van Schaik, Theresa Blume, Axel Bronstert, Jana Carus, Jan Fleckenstein, Nicola Fohrer, Katja Geißler, Horst H. Gerke, Thomas Gräff, Cornelia Hesse, Anke Hildebrandt, Franz Hölker, Philip Hunke, Katrin Körner, Jörg Lewandowski, Dirk Lohmann, Karin Meinikmann, Anett Schibalski, Britta Schmalz, Boris Schröder, Britta Tietjen
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(2014). The Brazilian Cerrado: Ecohydrological assessment of water and soil degradation of mesoscale catchments under intensive agricultural production. Ecohydrology
Hunke, P., Mueller, E.N., Schroeder, B., Zeilhofer, P.
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(2015) Climate or land use? - Attribution of changes in river flooding in the Sahel Zone using a simulation-based approach, Water 2015, 7(6), 2796-2820
Aich, V. Stefan Liersch, Tobias Vetter, Jafet Andersson , Eva N. Müller and Fred F. Hattermann
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2015. Soil changes under different land-uses in the Cerrado of Mato Grosso, Brazil. Geoderma Regional. 4 31-43
Hunke, P., Roller, R., Zeilhofer, P., Schroeder, B, Mueller, E.N.
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2016: Flood projections within the Niger River Basin under future land use and climate change. Sci. Total Environ., 562, 666-677
Aich, V., Liersch, S., Vetter, T., Fournet, S., Andersson, J., Calmanti, S., van Weert, F., Hattermann, F.F. and E.N. Paton
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2016: Time series analysis of floods across the Niger River Basin. Water, 8(4), 165
Aich, V., Koné, B., Hattermann, F.F. and E.N. Paton
