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

地球仪上的许多生态系统都受到土地使用或植被变化的影响，而这些变化是满足粮食需求、提高作物价格以及最近对生物能源生产的需求和气候变化影响所必需的。极端的土地使用变化往往对土地和水资源造成多方面的不利影响，如土地退化和荒漠化、土壤侵蚀加剧、养分耗竭、水资源受到农药和养分污染以及径流状况发生变化。例如，对于德国的勃兰登堡州，由于对生物燃料生产的需求增加，预计不久的将来农业生产将集约化，但是，玉米和油菜单作等集约化耕作方法对水和地球化学循环以及土地资源的影响尚不确定，并可能导致化肥、农药和水资源硝化作用的增加。巴西中部亚马逊盆地内的马托格罗索地区是另一个例子，大片天然森林被用于粮食和生物能源生产的农田取代，导致生态系统稳定性发生重大变化。不可持续的土地使用变化的第三个例子是美国西南部，那里的大规模过度放牧导致了不可逆转的持续荒漠化和土地退化，从肥沃的草地变成了沙漠灌木林。人们日益认识到生态水文过程在理解水文循环与植被和土地利用变化动态之间的联系方面的重要性，这就要求今后的研究必须考虑生态和水文过程之间的相互依存、相互作用和反馈机制。在本项目中，将通过在地球仪不同生态系统中进行详细的时间和空间分布的实地取样，了解生态水文过程。将开发一个微观和中尺度的综合生态水文建模工具，并将其应用于勃兰登堡（德国）、马托格罗索（巴西）和Jornada（美国新墨西哥州）研究地点的植被动态和土地使用变化情景。预计在水文学和生态学之间的界面开发和应用新的生态水文学、基于过程的建模工具，将为了解、控制和管理与气候、植被和土地使用变化有关的新问题和危机提供宝贵的见解。

Many ecosystems around the globe are affected by the impacts of land-use or vegetation change, which have become necessary to comply with food demand, raising crop prices and lately the demand for bioenergy production and the effects of climate change. Extreme land-use changes often lead to manifold adverse effects on the land and water resources such as land degradation and desertification, increased soil erosion, nutrient depletion, pesticide and nutrient contamination of water resources and changes in runoff regimes. For the state Brandenburg in Germany, for example, an intensification of agricultural production is predicted for the near future due to an increased demand for biofuel production, however the impacts of intensive farming methods with e.g. maize and rape monocultures on the water and biogeochemical cycle and land resources are uncertain and potentially lead to increased use of fertilisers, pesticides and nitrification of water resources. The Central parts of Brazil, in the Mato Grosso region within the Amazon Basin, is another example where large areas of natural forests were replaced by cropland for food and bioenergy production, resulting in a major shift in ecosystem stability. A third example of unsustainable land-use change is the south-western part of the United States, where massive overgrazing led to an irreversible, ongoing desertification and land degradation from productive grassland to desert shrubland. The increasing recognition of the importance of ecohydrological processes in understanding the link between the hydrologic cycle and vegetation and land-use change dynamics has enforced the need for future research to consider the interdependence, interactions and feedback mechanisms between ecological and hydrological processes. In this project, ecohydrological process understanding will be derived through detailed temporal and spatially distributed field sampling in different ecosystems around the globe. An integrated ecohydrological modelling tools at the micro- and meso-scale will be developed and applied to vegetation dynamics and land-use change scenarios for study sites in Brandenburg (Germany), Mato Grosso (Brazil) and Jornada (New Mexico, USA). It is expected that the development and application of the novel ecohydrological, process-based modelling tools at the interface between hydrology and ecology will provide valuable insights for the understanding, controlling and water and land-use management of emerging problems and crises related to climate, vegetation and land-use change.