Ecological Security Evaluation And Ecological Restoration Pattern In Three Gorges Reservoir Area

The research of the ecological security is a focus of concern around the world nowadays.Three Gorges Reservoir ecological securities is an important region of the national ecological control in the Upper Yangtze River,Whose ecological system supports the Yangtze River Basin's sustainable development and whose ecological security is concerned especially.Ensuring the ecological security of the TGRA,inhibiting its degenerate trend,recovering and rebuilding the vestigial ecosystem of the TGRA become an important part of the ecological barrier Construction and become a significant piece of national strategy requirement.The main contents contain:In perspective of ecological carrying capacities,define the concept of ecological securities;conclude and expand the research status and achievement at home and abroad about the ecological security;build relatively systematic theoretical frame preliminary;come up with some new thinking which is good for deepen research of the ecological security.Applying ecological footprint theory to research ecological carrying capacities and assess ecological security in TGRA is a new attempt in the ecological security assessment methodology,and the evaluate results have significant scientific reference value.Study the spatial differentiation with the method of GIS and deepen the cognition of the ecological security in TGRA;also offer new thought for the research of the ecological security in TGRA.Lucubrate and summarize the technical system of the vegetation recovery patterns and the eco-agriculture experiment demo mode from the theory of every model,experiment to popularizing demonstration of those patterns.The main conclusions contain:The main environmental issues in TGRA include:the serious soil erosion in upstream,the obvious ecosystem degradation and drawdown area of reservoir.The soil erosion in TGRA is estimated:the soil erosion gross is 11979.19×104t in 2005,the average soil erosion modulus is 2087t per square kilometer per year;the soil erosion gross is 13588.95×104t in 2000,the average soil erosion modulus is 2381t per square kilometer per year,which is lower than that in 2005 by 294t per square kilometer per year.The per capita ecological footprint is higher 0.57895hm2 than the per capita ecological carrying capacities in TGRA;The total ecological deficit is 11522193.34hm2,which is the 95.02 percent of the ecological carrying capacities.The existence of the ecological deficit shows that humans' ecological service requirement to the environment has exceeded its load,and it needs to import natural ecological resources to remedy the ecological deficit.We can find from the spatial assessment that:the secure and comparatively secure areas have accounted for 33.66 per cent of total area of the ecosystem;with the critically secure areas,Thus,the security position of the TGRA is far from being satisfactory.Lucubrate and summarize the technical system of the vegetation recovery patterns and the eco-agriculture experiment demo mode in TGRA;the article puts forward the theory of building the organism stereoscopic symbiotic mountain land ecological agricultural system type,model and technical system and building the mountain land ecological agricultural system type,model and technical system which is cyclic utilization with the materials;also,the dissertation lucubrates those typical models' structure experiment,demonstration and determine the strategy of the efficient ecological agricultural development.The typical models contain eco-fishery model,crop-cash crop-fruit composite ridge planting model,plant hedgerow model and so on.The results of the eco-fishery model show that the specific yield is higher by 4725 kg/hm2 than the average yield of the ordinary model and the increase production ratio is 53.7 per cent,but the economic benefit is increased by 143 per cent.The input-output ratio of the shaddock-pennisetum hydridum Plant hedgerow model is 3.97,which is the 2.6 times of the traditional management.Compare with the grain downward grade flatten culture,the average soil erosion decreases by 54.58 per cent.The economic benefit of the pig-marsh-fruit model can attain 3000-4000yuan and it can save cost by 2000yuan.Combing the practical situation of the TGRA and according to the eco-agriculture experiment' achievement,we put forward specific ecology recovering and rebuilding patterns;forecast the possible achieved level of the ecology recovering and rebuilding effectively and provide scientific foundation to the ecological planning and the socioeconomic development of the TGRA.