Loess Hilly Region Lucc And Regional Water Surplus Response Mechanism

The Land Use/Cover Change not only records the characteristic of the earth surface's change objectively, but also recurs the dynamic process of the landscape of the earth's surface. There is relationship between the Land Use/Cover Change and the areas eco-security. To discover the mechanism of the effect to the areas eco-security by the human, it is important to analysis the interaction between the human activities and the eco-restricted factors, and has an important effect for searching the order pattern of the human activities.By documentary review, consultation and comparison, taken loess hilly and gully area as an example, this dissertation has firstly analysis the spatial differentiation of social conditions and ecological background, the study areas is divided into six districts, which has special eco-social characteristic respectively. Secondly, based on the RS data resource, the Land Use/Cover Change is analyzed through the RS and GIS methods. Finally, through calculating the Regional Water Stress Index (As an abbreviation: RWSI) and Risk Index of Water Deficit (As an abbreviation: WESI), the responding mechanism between LIUCC and the regional water stress is discussed. Based on the revelation of the region's ecological and productive potential for agricultural development among districts, the ecological conservation of district and developing the integrated farming-livestock raising-forestry production within the region is designed.The main research contents and conclusions are as follows:(1) Revealing the spatial differentiation pattern of eco-economic background of the loess hilly and gully area in North China.Based on the characteristics of climate resources, soil resources and the potential and available combination of climate-soil resources, the dissertation also differentiates the spatial pattern of ecological background of the loess hilly and gully area. Thus the research areas have three type regions: high potential region, mid potential region and low potential regional. The low potential type mainly lies to the north of the study area. The mid potential regional type mainly lies to the middle part of the study area, and the high type tothe south. With 14 indexes relating to the production structure and the input/output of agricultural production at county level, the loess hilly and gully area in North China is divided into 5 production structure types in the main: farming, forestry, livestock raising, farming-to-livestock raising and livestock raising-to-farming, aided by two multivariate analysis methods like hierarchical clustering analysis (HCA) and fuzzy clustering analysis (FCA).Based the result of the spatial differentiation pattern of eco-economic background, the study area is divided into 6 districts.(2) Analyzing the LUCC of the loess hilly and gully area.Integrating the LUCC map of China, the vegetation map of China (the scale 1:1000000) and the actually GPS point, the LUCC map of the year of 1989 and 1999 is derived by the Maximum likelihood method. According to the method of Shi Pei-jun putting forward, the information of the LUCC of the study area is gained by analyzing the quantity and special change.(3) Studying the mechanism between LUCC and regional water stress in the loess hilly and gully areaCalculating the potential evapotranspiration and actually evapotranspiration, then, the quantitative relationship among land use types and the regional water stress is revealed. Through setting up an index WESI concerning LUCC and its regional water stress effect, the relationship among land use types and the regional water eco-security is analyzed from the whole area and districts level. The results of the analyses show that(l)from 1989 to 2000, the water deficit in the Region existed over time, though the variation range of the RWSI of the study area was diminishing;(2)comparing the RWSI of 1999 with that of 1989, the water deficit of the whole study area was abated a little, yet there were spatial variations within every ecological region, which meant in some places the water deficit was still serious;(3)for the whole study area, the order of WESI for every main land use type, from high to low, was grassland, arable land and woodland, implying its conditions favorable for pastoral practices;and(4)because of the spatial and temporal variations of the water regimes caused by the complicated geographical features in the Region, the WESIwas obviously different and the sequence of it varied somewhat among the ecological regions.