Evaluation Of Land Use Ecological Sensitivity In Barrier Zone Of The Three Gorges Reservoir Area

With the rapid development of society,the living conditions of human beings have been significantly improved.At the same time,the ecological environment has shown a more and more split trend.The rapid urbanization development is accompanied by the destruction of the land use system,the land use structure is gradually out of balance,and the comprehensive bearing capacity of land has not met the needs of human beings.Since the implementation of the Three Gorges project,the reservoir area has a total population of more than 400000 people who have been relocated.Three times of comprehensive water storage has caused a large number of land to be submerged,and the degree of regional ecological environment deterioration has gradually become unpredictable.In this study,the barrier zone of the Three Gorges Reservoir area is taken as the research area object,and the three pHases of LandsatTM / ETM +,MODIS surface temperature,vegetation coverage data products,DEM elevation data,soil data,meteorological monitoring data and road traffic network data in the study area in 2000,2010 and 2018 are taken as data sources.The barrier zone of the Three Gorges Reservoir area is impounded by "3S" technology and "mce-ca-markov" model The land use characteristics and ecological sensitivity evaluation in the early stage,early stage and stable stage are analyzed,and the ecological sensitivity of land use in 2027 is predicted.The main conclusions are as follows:(1)From 2000 to 2018,the total area of land use structure in the barrier zone of the Three Gorges Reservoir area is characterized by cultivated land > forest land > water area > construction land > grassland > unused land.From the perspective of quantitative structure change,the cultivated land,forest land,grassland and unused area are in the decreasing trend,while the water area and construction land area are in the increasing trend;the absolute value of land use dynamic degree of different land use structure types generally shows the characteristics of construction land > water area > unused land > cultivated land > forest land > grassland;the land use degree of cultivated land and forest land The land use degree of cultivated land,forest land and grassland shows an overall declining trend,while that of water area and construction land shows an increasing trend;the location advantages of different geographical units and land types are different,among which the location advantages of unused land at the head of the reservoir are very significant,and the location advantages of cultivated land and grassland lie in the belly of the reservoir,forest land and grassland The location advantage of unused land is at the head of the reservoir,and the location advantage of water area and construction land is at the end of the reservoir;from the perspective of the transfer flow of different land use,the transfer out area of cultivated land and forest land is large,and the transfer in area of construction land and water area is large,among which the transfer area from cultivated land to construction land is the largest area of all land types.(2)Based on the principles of natural geograpHy,environmental science,remote sensing and geograpHic information system,and through theoretical discussion and empirical analysis,four indexes including elevation,slope,slope direction,vegetation coverage,surface temperature,surface rainfall,soil type,soil layer thickness,soil pH,soil pH,are selected from the perspective of topograpHy,climate conditions,soil erosion and human interference There are 12 factors including the type of cover,the marginal degree of road and the marginal degree of water system to construct the ecological sensitivity evaluation system of land use in the study area.(3)In the barrier zone of the Three Gorges Reservoir area,the ecological sensitivity of land use is generally low.From 2000 to 2018,the ecological sensitivity values of land use are 4.8253,4.8305 and 4.6809,respectively.The overall trend of ecological sensitivity of land use is rising first and then declining.Among them,the area of light sensitive area is the largest and the area proportion of extremely sensitive area is the smallest.In 2000 and 2010,the ecological sensitivity index of different land use in the barrier zone of the Three Gorges Reservoir area showed the spatial distribution characteristics of water area > construction land > cultivated land > grassland > forest land > unused land;in 2018,the sensitivity of construction land is the highest and the grassland is the lowest;the ecological sensitivity index of cultivated land,forest,grass,water area and unused land is the lowest In general,the ecological sensitivity index of land use shows a downward trend,while that of construction land shows a slow upward trend.(4)Based on mce-ca-markov model,the conversion rules are formulated by constructing the limiting conditions and limiting factors.It is verified that the numerical accuracy between the simulated data and the actual data of the ecological sensitivity of land use in the 18-year study period is high,and the spatial kaapa value is 0.8292,which meets the prediction accuracy requirements.On this basis,the ecological sensitivity of land use in the study area in 2027 is predicted.The prediction results show that the ecological sensitivity of land use in the barrier zone of the Three Gorges Reservoir Area in 2027 is 4.3827,which is lower than that in 2018,and the ecological sensitivity of land use in the study area is generally low.In 2027,the area of different land use ecological sensitivity levels in the barrier zone of the reservoir area showed the distribution characteristics of light sensitivity,medium sensitivity,high sensitivity,insensitivity and extreme sensitivity.