| The Middle Route Project (MRP) under the South-to-North Water Transfer Scheme (SNWT) is an important component of SNWT in China, which plays an important strategic role for alleviating the shortage of water resource in Beijing and Tianjin, even in North China and improving the ecological environment in water deficient areas, and would have significant implications for the economic prosperity. As the source of water for the MRP, the Danjiangkou reservoir is one of the important strategic water resources areas in China. It not only is the significant key position in joining the the upstream and the middle and lower reaches of the Han River, but also determines the success of the MRP; and it not just provides residents in reservoir area with the human water use and ecological water use, more related to the human water use of residents of along the line of the middle and lower reaches of the Han River. The ecological and environmental conditions and water quantity and quality security of the Danjiangkou reservoir matters the coordinated growth of economic and social and environmental protection in the Danjiangkou Reservoir Area (DRA). However, since Danjiangkou Hydraulic Project starts to impound water in the 1970s, there were many inharmonious phenomena, including development disorderly of land resources and capture the scale survival of lakes and reservoirs ecosystems and so on, which may cause potential problems about ecological function, ecological security and ecological capacity of the DRA.Based on the monitoring on the land use condition and its change, this paper evaluated the spatial and temporal changes of land resources and analysed the main problem in the DRA. And the ecological capacity was calculated; eco-environmental vulnerability evaluation and land suitability evaluation analyzes were completed. Then, the situation of land utilization in 2020 was predicted and analysed and the eco-environment quality at that time was evaluated. Based on the research results above, the ecological function regionalization was studied, and this paper tried to bring forward several strategies and measures to different region, which will provide scientific basis for land resources management, planning and environmental construction in the DRA. The present study came to make important results and achievements as the following.(1) Based on sources of RS images, associated with the corresponding data and field investigation, this paper established different types of image signs and attempted to reveal the spatio-temporal dynamics of land use in the last 18 years from 1990 to 2007. The results indicated:as the socioeconomic development and the adjustment of policy in the DRA, land use had an obvious change reduction of cultivated land and the increase of the protective vegetation and residential land since 1990. The land resources were not fully utilized and the distribution of cultivated land is unreasonable, thus it has to be strengthened to protect land resources.(2)Based on the climate data, the land potential productivity was computed using Miami model and Thornthwaite Memorial model, On this basis, it calculated capacity of land resources, human carrying capacity in affluent condition, ecological capacity. The results indicated that the sustainable development capability in the DRA was better than average in Hubei because of the lower level of urbanization is not high, but ecological capacity in the DRA was less than average in Hubei. Grain production had larger space to promote in the DRA, and it was necessary to optimize the future land utilization pattern and raise agricultural productivity level.(3) Based on the environmental information data, an environmental numerical model was developed using spatial principle component analysis (SPCA) method. According to eco-environmental conditions and anthropic effects, vulnerability was classified into five levels: potential, light, medium, heavy and very heavy. The results indicated that eco-environmental vulnerability in the DRA was light overall. Regions with high eco-environmental vulnerability were located in the shallow hill, hilly areas surrounding Danjiangkou Reservoir and the regions with very low eco-environmental vulnerability were located in the Laojieling Nature Reserve in the north and Wudangshan Nature Reserve in the south. The eco-environment quality in the cities and counties was in the order of Xixia County>Shiyan City>Danjiangkou City> Yunxian County> Yunxi County> Xichuan County.(4) Ten factors relating to climate, topography, irrigation, soil type and vegetable were selected as evaluation indicators according to the regional characteristics of physical geography and land resource system and land suitability in the DRA was evaluated using limiting factor method and index sum method. Results showed that the area of arable land resources was 27.83% of the total in the DRA, the east part over western; the area of the suitable grassland was 28.45% of the total, which was mainly distributed in hill areas surrounding Danjiangkou Reservoir and the mountains in the northwest; the characteristic of the suitable forest land area was the northwest and northeast over southwest part, accounting for about 38.40% of the total area.(5) The situation of land utilization in 2020 was predicted using CA-Markov model. The forecasting results showed that if no regulatory measures, the ecological environment may deteriorate further in 2020 in the DRA. According to the progress of the Danjiangkou dam heightening project and regulation measures of land use, the forecasting results showed that the arable land, unexploited land resource will decrease obviously and forest land, garden land will increase, which will promote well recycling of ecological environment and in source area and the development of society, economy effectively in the DRA.(6)Based on forecasting result, five factors were selected as evaluation indicators, including the biology abundance index, the vegetation coverage index, the water network density index, the land degradation index and pollution load index, and the eco-environment quality was evaluated. The results showed that eco-environment quality of cities and counties could enhance; Yunxian County were greatest improved, then Yunxi County, and The smallest change was Xixia County. The eco-environment quality change for the better in the cities and counties was in the order of Yunxian County>Yunxi County>Danjiangkou City>Shiyan City>Xichuan County>Xixia County. Ecological environment improvement was a long-term task with long construction period and effective slow.(7) Based on the research results above, the ecological function regionalization was studied.The DRA was divided into three functional regions:the ecological security zone (red line zone), ecological barriers zone (yellow line zone) and ecological control zone (blue line zone), the area of which are 5544.69 km2,5961.57 km2,6412.61 km2 (30.94%,33.27% and 35.79%, respectively). The red line zone mainly included water conservation zone, nature reserves, important wetlands and basic farmland, which should be strictly protected and disorderly excessive land development, should be strictly limited. The main sensitive region of the yellow line zone was the aquatic environment of lakes and reservoirs, it is essential to strengthen reservoir restoration projects, enhance soil and water conservation and control non-point pollution effectively around the reservoir and riparian areas. In the blue line zone ecological environment construction should proceed by land intensive utilization, ecological agriculture and mine rehabilitation.
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