【作者】 曾加芹；

【导师】 牛树奎； 欧阳华；

【作者基本信息】 北京林业大学 ， 生态学， 2007， 硕士

【摘要】 本文以西藏地区1985年和2000年两个时期土地利用数据(1：10万)为基础，结合野外调查，并在ARC/GIS软件支持下，构建研究区景观类型数据库。在此基础上利用FRAGSTATS软件计算景观格局指数；运用SPSS统计软件中典型相关性分析对景观格局变化的驱动力进行分析；最后利用ARC/GIS软件对西藏地区景观的生态安全进行了评价。结果表明：(1) 1985～2000年，西藏地区景观组分发生了显著的变化：未利用地、建筑及交通用地、灌木林地及疏林地面积增加，农业用地、森林、草地、河流及湖泊、冰雪地面积减少；草地在8种景观要素中转出面积最大，80.2％向未利用地转换；转入率最大的是居民建筑及交通用地，81.6％以上来源于农业用地、草地和水域；未利用地净增加面积70215.25km~2，主要来源于草地、林地和水域。(2) 1985年～2000年，西藏地区整体景观斑块数、多样性指数、均匀度增加，形状指数、分维数、聚集度及优势度减小，西藏地区景观向着破碎化、多样化及规则化方向发展。对西藏七个地区的景观指数进行对比分析发现，各地区景观格局差异较大，1985年到2000年，各个地区景观形状向规则化方向发展，异质性和连通性增加。(3)应用Arc/View3.2等软件，建立景观类型的初始转移矩阵，利用马尔柯夫模型对未来景观格局进行预测，结果显示未利用地、建筑及交通用地等面积增加，而草地、森林等绿地面积减小；定性与定量分析相结合对西藏景观格局变化的驱动因子进行分析发现，西藏景观格局变化受海拔、降水、气温等自然因子的影响，然而人口、牲畜量的增加以及经济的发展等人类活动的加剧起着关键性作用。(4)对西藏地区景观生态安全性进行综合评价，结果表明：2000年西藏地区生态安全性指数比1985降低。基于评价结果，笔者提出了尊重自然生态过程，合理安排人类活动强度和方式等针对性的保护措施及方案，为西藏地区景观生态安全及景观格局优化提供理论依据。更多还原

【Abstract】 Based on two periods of land use data in Tibet in 1985 and 2000(scale 1:100,000) and combined with field investigation and ARC/GIS software support, the database of landscape classes was established. The landscape indexes were calculated by Fragstats. The landscape pattern change driver was analyzed by the canonical correlation analysis of SPSS. Finally, assessment system was built, and the ecological security of Tibet landscape was evaluated by ARC/GIS. The conclusions were as following:(1) Compared to 1985, the area of each landscape class altered notably in 2000. Unused land, construction and communication land, shrub and woodland increased while agriculture land, forest, grassland, drainage basin, lake and ice land decreased. 80.2 % of the grassland transferred into unused land, which was the most in transfer-out. The construction land was the most in transfer-in, 81.6% coming from agriculture land, grassland and drainage basin. Unused land increased by 70215.25 km~2, most coming from grassland, forest and drainage basin.(2) From 1985 to 2000, the landscape pattern of the Tibet changed noticeably, the patch amount, diversity, and equality increased, while the dominance, shape index, connectivity and fractal dimension decreased. The landscape pattern developed towards more fragmented, diversified and simplified. By comparing and analysing landscape index of seven regions in Tibet, great difference existed among them, landscape heterogeneity and landscape connectivity of seven regions was increased between 1985 and 2000.(3) The initially transformation matrix of landscape elements was built by applying Arc/View3.2 and Excel. The Markov forecasting showed that under the same disturbancesbetween 1985 and 2000, unused land, build-up land and shrub land area increased, however, grassland, water, agriculture land and other types decreased year by year. The landscape pattern changes driver analysis showed that Tibet landscape dynamics is constrained by height, rainfall, temperature and other natural factors, especially the increase in population, livestock production increased, residential building sites increased, etc. played a key role.(4) By establishing an evaluation system and using AHP to determine the evaluation factors weights, the valuation model of ecological security was built in this paper and the overlay function of raster-GIS was used to make a result map. Tibet regional landscape security synthesis evaluation results: in 2,000 compared with the 1980s the ecological security index of Tibet region decreased. Based on the of the result above, the author brings forward the protective measure and project of respecting the natural ecology process, arranging human activities intention and ways rationally, which can offer academic gist for landscape ecological security and landscape pattern optimization in Tibet region.更多还原