【作者】 万利；

【导师】 陈佑启；

【作者基本信息】 中国农业科学院 ， 农业遥感， 2009， 博士

【摘要】 城乡交错带是城乡发展与建设的集中地带。该区域社会经济活动活跃,人地关系严峻,矛盾比较尖锐,生态环境敏感而脆弱,被喻为研究土地利用/土地覆被变化及其生态环境效应的“天然实验室”,探究该区域土地利用变化及其对生态环境的影响研究具有重要的理论价值和实践意义。目前有关城乡交错带土地利用变化对生态环境影响的综合评价和分析尚不多见,运用多种方法,从多角度开展城乡交错带生态环境动态、综合分析的案例更是缺乏。由于北京独特的政治、经济、社会地位,城乡交错带的缓冲地带和绿色屏障作用显得尤为重要,开展城乡交错带土地利用变化对生态环境的影响研究对首都社会经济与生态环境协调发展具有重要的现实意义。本文选择北京市朝阳区(城乡交错带的内边缘区)、顺义区(城乡交错带的中心区)和密云县(城乡交错带的外边缘区)三个典型区(县)为研究区域,综合运用RS和GIS技术,以区域生态环境演变过程为主线,在分析研究区土地利用变化规律的基础上,从生态系统服务、生态环境质量和生态安全三个层次开展城乡交错带1996-2005年间土地利用变化对生态环境的影响研究,并针对城乡交错带土地利用变化特点和存在的主要生态环境问题提出生态可持续发展的建议。主要研究结论如下:(1)城乡交错带土地利用变化特征:土地利用结构变化明显,动态度变化空间分异明显,类型转化较快,景观格局变化较大;尤其表现为建设用地向外扩展速度快且规模大,侵占大量耕地,耕地破碎化和离散化趋势明显。(2)基于GIS技术完成八个生态系统服务功能价值的空间格局和动态变化情况分析。结果表明:1996-2005年间,城乡交错带各生态系统服务功能价值的空间分布格局变化特征各异;同时,城乡交错带各区域的生态服务功能价值结构变化不一,内边缘区(朝阳区)生态系统中仅净化水质及生物多样性服务功能有所增强,其它服务功能均有所减弱;中心区(顺义区)生态系统的涵养水源、净化水质、保持土壤和净化环境等功能有所减弱;外边缘区(密云县)生态系统的涵养水源、生物多样性和净化环境等功能有所减弱。(3)基于格网方法构建生态系统服务价值指数(ESVI),以更好地反映生态系统服务价值的空间分布格局和整体变化趋势,且体现出各行政单元内部差异,定量化分析研究区土地利用变化引起的区域生态系统服务价值变化特征。结果表明,1996-2005年间:①生态系统服务价值持续减少,且区域分异明显;②生态系统服务价值的低值区、较低区和中值波动区与建设用地扩展的关系非常密切,后者是导致该区生态系统服务价值下降的直接原因;③生态系统服务价值与GDP的比值远远低于全国平均水平且呈持续下降趋势,反映土地利用结构呈非良性变化趋势,区域发展一定程度上是以牺牲生态系统服务功能为代价;④生态系统服务价值变化趋势与其主要构成者耕地、水域的变化趋势保持一致,耕地、水域的生态系统服务价值均随各自面积的减少而下降。(4)综合考虑城乡交错带的自然环境、景观结构、农业污染和人为干扰四个因素,探索出城乡交错带土地利用变化的生态环境效应评价指标体系和评价模型,实现生态环境效应的动态评价。结果表明:①城乡交错带生态环境质量优劣差距较大,生态环境质量较好地区(一级和二级)约占总面积的60%,生态环境质量较差地区(四级和五级)约占总面积的35%,生态环境质量一般地区(三级)仅占研究区总面积的5%;②各生态环境分区的面积变化不同步,一级区和三级区的面积呈先增后减趋势,二级区和四级区的面积呈先减后增趋势,五级区呈递减趋势;③研究区总体生态环境质量处于一般水平,2005年较1996年和2000年有所下降,但各区县生态环境状况差异明显;④1996-2005年间,朝阳区生态环境状况有所改善,顺义区和密云县生态环境呈退化趋势。(5)基于景观稳定性指数构建区域生态安全指数,开展城乡交错带的生态安全动态评价与分析。结果表明:①人类活动对城乡交错带生态环境影响强烈,斑块数量、破碎度、多样性指数和分形维数均呈增加趋势;②生态安全指数受人为干扰影响较大,局部区域景观类型从1996年的零散分布发展至2005年的连片分布,整体生态安全强度的空间分布不均匀性增强;③从城乡交错带内边缘区(朝阳区)到中心区(顺义区)和外边缘区(密云县),生态安全指数值呈由低到高的变化趋势,且低值区随城市化进程的加快而扩大,表明生态安全指数能定量评价区域生态环境状况及其演变趋势;④各景观类型的生态安全等级构成不一,反映各景观类型的生态安全水平不同,其中林地最高,建设用地最低。(6)研究区现阶段的生态环境问题日益突出,主要表现为:①非农用地扩展迅猛,绿化隔离带不断被蚕食,生态系统的初级生产功能降低;②土地资源浪费严重,土地系统功能退化;③工业“三废”和生活垃圾加剧环境污染;④畜牧业发展迅速,环境污染加重;⑤滥用农药、化肥和农膜,土壤污染严重。本文针对这些问题提出城乡交错带生态可持续发展的建议,从以下五方面入手:一是加强土地利用规划,合理开发利用土地资源;二是重视绿化隔离带的建设和保护;三是加快城镇环境的综合整治;四是大力发展循环经济,减轻污染负荷;五是控制农村面源污染,抓好生态示范区建设。更多还原

【Abstract】 The rural-urban fringe is the frontier of urban land expansion, which has active socio-economic activities, serious man-land relationship, sharp contradiction , sensitive and fragile ecological environment, and is known as "natural laboratory" for the research of environmental effects. So the study on land use change and its environmental impact in rural-urban fringe has a higher theoretical value. However, the synthetic evaluation and analysis about the impact of land use change on ecological environment is still rare. Due to the unique political, economic and social status of Beijing, it plays an important role in the effect of buffer zone and green barrier of the rural-urban fringe, and the study on land use change and its environmental impact in rural-urban fringe has an important practical significance to harmonious development of society, economic and ecological environment.In this paper, three typical regions of Chaoyang District (interior fringe area), Shunyi District (central fringe area) and Miyun County (exterior fringe area) in Beijing are selected as the study area. Meanwhile, the RS and the GIS techniques are employed to explore the effects of land use change on ecological environment in terms of ecosystem service, ecological environment quality and ecological security. According to the results, several reasonable suggestions for sustainable development of ecological environment are proposed. The main conclusions are as follows:(1) In rural-urban fringe of Beijing, the land use structure changes obviously and the change of land use dynamic degree has obvious spatial differentiation. Meanwhile, the land use types keep rapid conversion and the landscape patterns also change very fast. Furthermore, the fragmentation and decentralization trend of cultivated land is clearly and the construction land expands in high speed and large scale.(2) The temporal and spatial dynamic trend of ecosystem service value (ESV) in rural-urban fringe of Beijing from 1996 to 2005 is analyzed by using GIS technique. The results show that different ESV has different characteristics of spatial pattern change. Meanwhile, the ESV structure changes differently in Chaoyang District, Shunyi District and Miyun County. In Chaoyang District, most of the ecosystem services functions are weakened except water purification and biodiversity. In Shunyi District, some function of the ecosystem services are weakened, for example, water conservation, water purification, soil conservation and environment purification. In Miyun County, some function of the ecosystem services are weakened, for example, water conservation, biodiversity and environment purification.(3)In order to reflect the temporal and spatial dynamic trend of ESV in the study area from 1996 to 2005 and the internal differences in each administrative unit, ecosystem service value index (ESVI) is constructed by using the grid spatial analysis technique of GIS. The results show that①ESV continues to decline from 1996 to 2005, and the regional differentiation is obvious;②t he area of low ESV has been expanding gradually with the expanding of construction land, which results in the downward trend of ESV in the study area;③The ESV-GDP ratio in the study area is far below the national average and shows substantial decrease trend, which reflecting land use structure changes in non-positive trend. To some extent, the regional economic is developed at the price of ecosystem services;④The results suggest that the change trend of ESV is consistent with that of cultivated land and water. ESV of cultivated land and water declines with the decrease of their area.(4)Four factors including natural environment, landscape structure, agricultural pollution and human disturbance are introduced to establish the ecological environment effects evaluation index system and model, which realize the dynamic evaluation of ecological environment effect. The results show that①The ecological environment quality has a relatively large disparity in the rural-urban fringe. The area of good quality, bad quality and common quality of ecological environment in the study area occupy 60%, 35% and 5% respectively.②The classification area of ecological environment change asynchronously.③The ecological environment quality of the whole area, which is in the general level, has shown an decreasing trend.④From 1996 to 2005, the ecological environment status in Chaoyang District has improved while Shunyi District and Miyun County show a downward trend .(5)The temporal and spatial dynamic trend of ecological security in rural-urban fringe of Beijing from 1996 to 2005 is analyzed in terms of landscape ecological security index (ESI), on the ground of landscape ecology theory and the stability of landscapes. Semivariogram analysis and Kriging interpolation are conducted to get the distribution map of ecological security. The results show that①The ecological environment is strongly influenced by human activities, and the landscape indexes of patch number, landscape fragmentation and the fractional dimension have all shown an increasing trend in the study area;②Human activity has much influence on the ecological security index, giving rising to quite uneven spatial distribution of ecological security in the whole area;③The ecological security index (ESI) can be used to quantitatively evaluate the ecological environment and its evolution direction. The ESI takes on an ascending tendency from Chaoyang District through Shunyi to Miyun counties, and the area of low ESI has been expanding gradually with the acceleration of urbanization of Beijing;④Different landscape types have different level of ecological security. The ecological security level of forest landscape is the highest, and the construction landscape is the lowest.(6)Targeting at the existing problems of ecological environment in rural-urban fringe of Beijing, the author puts forward several reasonable suggestions for sustainable development of ecological environment: strengthening land use planning, developing and utilizing land resources reasonably; emphasizing the construction and protection of greenbelt; speeding up the comprehensive improvement of urban environment; developing circular economy and reducing the pollution load; controlling the rural non-point source pollution and constructing ecological demonstration.更多还原