【作者】 徐伟；

【导师】 孙保平；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2006， 博士

【摘要】 荒漠化是当前世界上最严重的资源与生态环境问题之一。北京由于所处区域构造及气候地理位置，生态环境直接受荒漠化的严重威胁。近几年，北京受风沙袭击的沙尘天数和程度都远超过往年，首都经济、社会发展与人民生活均受到严重影响。 北京市沙化土地依据地貌特征，土壤质地主要划分为山地、丘陵向平原过渡地带、平原三种类型。本研究通过选取康庄、南口、永定河三处典型风沙危害区为研究对象，借助遥感技术、地理信息系统技术、全球定位技术、景观生态学理论和相关数学研究方法，对八十年代、九十年代和2000年以后三个时期的景观动态进行分析和比较，进而探讨北京市土地沙化景观类型的动态变化。主要研究成果如下： 从八十年代至今，北京沙化土地景观类型发生巨大变化。其中，以康庄、南口、永定河研究区为代表，沙荒地面积大幅度减少，由2117.03hm~2、320.49hm~2、3950.5hm~2，分别减少到1249.65hm~2、160hm~2、1542.74hm~2；减少了40.97％、50.08％、60.95％。 通过选取相关景观指数对研究区景观类型进行分析可知，景观破碎化程度的变化趋势是：康庄风沙危害区先增加后减缓、南口风沙危害区持续增加、永定河风沙危害区先增加后减缓；对研究区景观类型的变化的分析表明，变化的原因与研究区所处地理位置，社会经济发展背景和人为干扰、政策导向密切相关。 对影响研究区景观动态变化的主要因素分析可知，研究区主要受自然和人为两种条件影响最大。自然因素中，沙化土地变化主要与地貌特征、地表物质、降雨、温度、大风、水文条件等因素关系较密切；人为因素中，主要受人口增长、农业结构调整、林业工程实施和社会经济发展背景等因素的影响。 依据景观结构变化特征及主要影响因素分析结果，建立了北京市沙化土地综合效益评价指标体系，为效益评价以及进一步决策提供了科学的依据。 运用AHP法定量评价模型、多层次模糊综合评价方法结合沙化土地综合效益评价指标体系对不同区域沙地特点进行分析评价，结果表明：生态效益：康庄＞永定河＞南口；经济效益：永定河＞南口＞康庄；社会效益：南口＞康庄＞永定河；综合效益：永定河＞南口＞康庄。 景观生态模式建立：参照综合效益评价结果并结合不同景观类型的发展特点，依据当地的区域优势，建立合理、经济、高效的沙地景观模式：康庄研究区—景观生态型荒滩综合治理防护模式；南口研究区—人工干预条件下近自然恢复砂滩治理防护模更多还原

【Abstract】 Desertification is one of the most serious resource and eco-environment problems in the world at present. In the condition of region structure and climate geography location, Beijing’s ecological environment has been severely affected. In recent years, the number of sandy days and the extent of sandy days influenced by wind and sand far overrun those in ancient years, so the economy, social development and the people’s lives are all affected severely.According to the terrain and topographical features, the sandy land in Beijing mainly were divided into three types that are mountain ground, the transition zone from hill to plain and plain. In this paper, Kangzhuang, Nankou and Yongding River were selected as typical damage regions, in virtue of the Remote Sense Technology, Geography and Information Systems Technology, Global Localization Technology, landscape ecological theory and some mathematic analysis methods to analyze and compare the landscape dynamic process in 1980s, 1990s and three periods after 2000. and to discuss the dynamic changes of sandy landscape type. The main research results were listed as follows:Since 1980s, the sandy landscape type has experienced great change. Take Kangzhuang, Nankou and Yongding River as representation, the bare sandy land area decreased greatly, from 2117.03 hm~2、 320.49 hm~2、3950.5 hm~2 to 1249.65 hm~2、 160 hm~2、 1542.74 hm~2 respectively, the proportion is 59.03%、 49.92%、 49.05%。By selecting landscape indexes,to analyze landscape types in the studied area, we can see that the landscape breaking extent tendency is: aggravating at first and then slowing up in Kangzhuang sand and wind damage region, persisting increasing in Nankou sand and wind damage region, aggravating at first and then slowing up in Yongding River sand and wind damage region, which were nearly related to the geography location of studied area, social economical development background, man-made interference and policy guidance.By analyzing the major factors influencing landscape dynamic change, we can see that the important factors are nature and artificial factors In the nature factors, the sandy land change has more close correlation with terrain and topographical features, surface substance, precipitation, temperature, gale and hydrographic factor. And it is mainly affected by the artificial factors such as population incensement, agriculture structure adjustability, the implement of forest engineering and social economical development background and so on.According to the results of landscape structure changes characters and major influencing factors, the indicator system for the comprehensive benefit assessment was built, which can provide scientific更多还原