城市边缘区土地利用变化及其生态环境效应

【作者】 秦泗刚；

【导师】 王慧；

【作者基本信息】 西北大学 ， 环境科学， 2005， 硕士

【摘要】 土地利用及生态环境效应是全球环境变化研究的重要组成部分,是可持续发展研究的核心问题。本文以西安市城市边缘区南区为例,采用1990年、1996年、1998年、2000年和2002年五个代表年的土地利用数据,以及1990年和2002年两期的土地利用现状图,应用GIS空间分析软件,对研究区内的土地利用空间结构、土地利用变化的区域差异以及土地利用变化引起的生态环境质量变化进行相对定量的分析和评价,得出以下结论: (1)城市边缘区是区域土地利用变化异常活跃的区域之一,是城市生态环境的“敏感地带”和“脆弱危机带”,由于生态环境变化的复杂性、易变性、过渡性和脆弱型,其被誉为生态环境变化研究的天然“实验室”。城市边缘区土地利用变化最根本的特性是城镇村及工矿用地(居工地)“遍地开花”,大面积增加,而耕地却大量减少,空间上被蚕食。 (2)城市边缘区土地利用空间结构具有明显的规律性,土地利用类型在空间分布呈现出距离层次性,即随着距离城市主城区的增加,其主导土地利用类型发生了规律性变化,表现为:居工地主导型→耕地与居工地主导型→耕地主导型→耕地与林地主导型、林地与耕地主导型→林地主导型。 (3)研究区土地利用变化以耕地和居工地变化为主,耕地变化为主和以居工地变化为主的乡镇、街道办的数量占研究区内乡镇、街道办总数目的94%。其中,耕地变化呈现出明显的“半圈层”式的空间格局:以一级耕地变化强度区为核心,向外围(研究区东、南、西三个方向)逐级递减。居工地变化强度较大的乡镇、街道办同时也是耕地变化较大的乡镇、街道办;居工地变化在空间上表现为一级变化强度区呈现出由北向南空间延伸拓展的趋势,这与西安市城市南北方向发展轴的轴线效应不谋而合。 (4)利用国内外学者对不同生态系统服务功能价值测算的结果,构建土地利用变化的生态环境质量指数,指出1990-2002年间,研究区内总体生态环境质量出现微弱的衰退。在空间格局方面,生态环境质量低值区与较低区东西对称,而生态环境质量高值区与较高区在空间上表现为东西向延伸,此格局必将对区域生态环境造成深远的影响。 (5)研究区生态环境质量变化主要是由耕地、园地、居工地变化而引起的,其中,由耕地向居工地转化是区域生态环境质量衰退的最主要原因,而耕地向园地方向的转更多还原

【Abstract】 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 dominated→farmland with resident and industry land dominated→farmland dominated→farmland and woodland dominated→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 land→garden plot to resident and industry land→woodland to resident and industry land; and the pattern that eco-environment quality worsen shows farmland to garden plot →farmland to woodland.更多还原