Interactions of geomorphology, hydrology and ecology in natural and artificial restored catchments on the Chinese Loess Plateau

The Loess Plateau of China comes from aeolian deposits and its landform evolution is sensitive to climate change and land use/land cover conversion. If without the regulation of vegetation, the relationship between loess geomorphic evolution and hydrology is mainly controlled by physical erosion processes and the catchment system does not has the function of ecosystem evolution and adaptation. From the perspective of catchment’s ecosystem management, catchment processes without any vegetation or ecological measures on the Loess Plateau of China is a rapid lateral transportation system, which can be called fast system (fast soil and water loss) and its landform change is dominated by rapid geomorphological evolution. If vegetation or ecology measures are added to the physical system, the catchment has the function of evolution and adaptation, and the elements of geomorphology-hydrology-ecology form the function of mutual feedbacks and coupling evolution processes. In this system, geomorphology regulates the distribution of hydrology, hydrology controls the distribution of vegetation, and vegetation in turn regulates the development of hydrological processes and landform evolution. Therefore, in small catchments with ecological interventions, the catchment system continues to evolve under the influence of vegetation. The surface processes will slow down under the impacts of vegetation, the geomorphic evolution will weaken, and the vertical flux of matter and energy will increase in the vegetation-regulated catchment system, which can be called slow system (slow soil and water loss). Therefore, the coupled interactions of geomorphology, hydrology and ecology is of great significance for catchment’s ecological management on the Loess Plateau of China. Overall, soil and water conservation on the Loess Plateau should not be a no-living project, but should have the characteristics of self-regulation, adaptation and evolution, and eventually form a self-stabilizing system. That is, after physical and ecological combination treatment, the catchment would be changed from a fast mass loss system to a slow mass loss system and eventually to an equilibrium system.