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Study On Land Use/Cover Change And Its Impact On Ecological Security

Posted on:2007-03-19Degree:DoctorType:Dissertation
Country:ChinaCandidate:S LiuFull Text:PDF
GTID:1101360185476231Subject:Soil and Water Conservation and Desertification Control
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Ecological security is an international warm topic in scientific fields at present, which reflects the interaction between the social-economic activities of human beings and the ecological environment. As a kind of human activity, land use and land cover change (LUCC) can eventually affect the ecological security in a certain area.A case study was conducted in Xining and Zhalute Banner, to find out how and in what extent the land use/land cover change affect the ecological security. The data were collected through interpretation of remote sensing images, field investigation, historical materials and maps. The collected data were analyzed by using remote sensing and GIS software, including ERDAS, MAPINFO and ARCINFO, and by statistical software such as SPSS and EXCEL. The research findings were as follows:1. Research into the land use / land cover changeThe land use types of the case study site can be classified into woodland, shrub-land, grassland, cultivated land, human settlement, water body and bare land, according to the interpretation to the satellite images of 1987, 1996 and 2002 with reference to the historical maps and GPS positioning survey data on-the-spot. Based on the classification, transfer matrixes of LUCC from 1987 to 1996 and from 1996 to 2002 were made and the features of LUCC were analyzed. The general trends of LUCC in the Xining from the matrix show: â‘  the areas of woodland, cultivated land and human settlement are on the increase, while the areas of shrub-land, grassland and bare land on the decrease.â‘¡also the area of woodland is on the increase as a result of conduction of the subject of green south mountain and north mountain in Xining , but limited by the natural conditions its area is small and scattered. â‘¢the areas of shrub-land and grassland are on the decrease as a result of the conduction of the subject of green south mountain and north mountain in Xining and the increase of cultivated land and human settlement with economical grow. ? the area of bare land is on the decrease, but by the research of its distribution change, we find many original land become bare land in some region.2. Research into the assessment on the ecological security conditionsMost ecosystems in the case study site have been degrading. This judgement is based on the analysis of the restoration to the original natural landscape (types) by DEM modeling, with special reference to the topography (elevation, exposure and slope), soil nutrients and river system structure.Three types of soil fertility distribution pattern were obtained by using Kriging methods, that is, good fertility, above 3.5% of organic matter; medium fertility, 2-3.5% of organic matter; and poor fertility, below 2% of organic matter.The productivity and growth of vegetation in the case study site were estimated through analysis of the normalized difference vegetation index (NDVI). The growth and productivity of vegetation in North were far better than that in South.The gradation of the ecological security in the case study site was determined by...
Keywords/Search Tags:LUCC, Xining, Zhalute Banner, ecological security, restoration of natural landscape, NDVI, assessment of ecological security
PDF Full Text Request
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