岷江上游典型时期景观格局变化及驱动力初步分析

岷江上游地区是我国一个重要的大尺度、复合型生态过渡带，也是一个生态系统脆弱区，研究其景观格局的变化，对于构筑我国的生态格局安全具有十分重要的意义．本研究利用岷江上游地区1986、1995、2000年3个时期的TM影像，分析了3个时期的景观特征以及变化．结果表明，岷江上游整体景观水平以草地景观为基质、森林景观以及其他景观类型作为斑块镶嵌其中．森林景观面积经历了从1986～1995年的上升，而后到2000年的下降过程；草地景观高盖度草面积不断减少；同时，森林景观和草地景观斑块总数一直增加，破碎化趋势明显．岷江上游景观格局变化的驱动因子主要是日益增加的人口数量而导致的人为干扰，包括对土地利用方式与利用强度的改变、森林资源的掠夺性开采、草地资源的过度放牧以及气候、土壤等自然因素的变化．

Landscape pattern change at the upper reaches of Minjiang River and its driving force

The upper reaches of Minjiang River is an ecological sensitive and vulnerable area in southwest of China.It is of great significance to the ecological pattern safety in China.In this study,we analyzed the landscape pattern change through the interpretation of TM imageries in 1986,1995 and 2000.The results showed that the matrix landscape in this area was grass landscape.Forest landscape patches were embedded in the grass landscape.The forest landscape area increased from 1986 to 1995 and decreased from 1995 to 2000.However,the number of patches of forest landscape was increasing during all the time.This suggested that the intensity of anthropogenic disturbances including harvesting,forest landscape reclaiming and excessive grazing were persistently increasing from 1986 to 2000.The ecological driving forces of the landscape change in this area were the intensified anthropogenic disturbances as a result of the population boom including the predacious harvesting of forest and excessive grazing.The natural disturbances such as the global climatic change also partly influenced the landscape change in this area.