The Urban Fringe Land Use Change And Its Ecological Environment Effects

Research on land use change and associated effects on eco-environment is the important part of research on global environment change, and is also the key content of the sustainable development study., As a sample of the south urban fringe in Xi'an, we adopt the land use data in 1990, 1996, 1998. 2000 and 2002 as the digital source, and use the land use images in 1990 and 2002 as the graphic source.Based on GIS technique, land use spatial structure, area difference of the land use change, land use change and associated effects on eco-environment in this area were studied with methods of quantitative analysis and appraisement.. In the end , drive some theoretical and practical conclusions:(1)Urban fringe is one of the most active area of land use change, For its complexity, changeability, transition and fragility, it is honored as an inartificial "laboratory" on the study of environment change, The primary characteristic of the urban fringe is that more and more lands are transferred to resident and industry land but the farmland are decreased and nibbled by other lands.(2) The spatial structure of the land use in urban fringe shows apparent laws: With the distance away from the city the distribution of different types of land takes on regular changes. Most changes obey the evolvement order of land: Resident and industry land dominatedâ†'farmland with resident and industry land dominatedâ†'farmland dominatedâ†'farmland and woodland dominatedâ†'woodland dominated.(3) Land use change in this research area mainly lies in the change of farmland, resident and industry land. The spatial change of farmland appears half-circle pattern: with the region where farmland changes a lot as the core , the intensity of the land change in the periphery part, which includes the regions to the east ,south and west of the research area, decays with the distance longer and longer step by step. The change of resident and industry land shows that the intensity of change extends from the north to the south, which happens to accord with the development axis from the south to north of Xi'an city.(4) Based on the conclusions of different ecosystems value that the scholars home and abroad drawn, the quality index of eco-environment on the land use change is formed, it shows that the overall environmental quality of this research area worsen a little. Thespatial pattern that the lowest-value and the little lowest-value region are symmetrically located in the east and south part but the highest-value and the little highest-value one extend from the east to west, this spatial pattern have a far-reaching impact on the environment of the whole region.(5) The change of the eco-environment quality in this research area is mainly caused by the variety in farmland, resident and industry land and garden plot, especially the transformation of farmland to resident and industry land being the main reason for the worse ecosystem quality of the whole region, and it is the transformation of farmland to garden plot that uppermost help to better its environmental quality. Meanwhile, the reasons for the change of environmental quality show a series of spectrum in space, which means that the reasons vary with the different distance from the city, The regions where eco-environment quality betters include the parts in which the land transformation of the following dominated:: farmland to resident and industry landâ†'garden plot to resident and industry landâ†'woodland to resident and industry land; and the pattern that eco-environment quality worsen shows farmland to garden plot â†'farmland to woodland.