北方农牧交错带一直是我国生态脆弱区,近二十年来,生态建设和气候变化深刻影响了该地区土地利用格局.为揭示该区人地关系复杂变化,为土地合理利用指明方向,选取县域尺度作典型案例研究.基于沽源县三期TM遥感数据,运用GIS空间处理技术和景观格局分形等主要指数定量分析景观格局变化.结果如下:(1)1988年至2008年间沽源县土地利用变化显著,草地、林地总面积先减少后增加;耕地面积变化表现为先增加后减少,总体呈减少趋势;主体景观面积呈波动性变化,土地利用结构变化较大.(2)1988～1998年所有景观类型分维数都表现递增趋势,土地利用斑块形态不规则程度增加,景观的复杂性增高.1998～2008年林地景观分维数降低,景观趋于稳定;耕地、草地的分维数不同程度增加,其边界表现出不同程度的复杂化,景观斑块稳定性降低.%Under the influence of human beings and climate change, the landscape pattern of the farming-pastoral zone in northern China changed intensively. Although many policies were carried out here, it is still fragile in environment.To analysis the reasons resulting in the change of landscape pattern and provide the strategy optimizing the land use types, we studies the characteristic of change of landscape pattern in middle-scaling. Basing on the RS and GIS technology, maps of land use types was obtained representing years of 1988, 1998 and 2008 separately. Fractal dimension and stability index were calculated to analysis the change of landscape patterns quantitatively. It was found that: the land use changes of Guyuan county were significant from 1988 to 2008, the total area of grassland and woodland first reduced then increased; cultivated land increased first then reduced, generally was decreasing trend; The areas of main landscape types showed fluctuation changes and whole land use structure change greatly.The fractal dimension of all landscape showed increasing trend; Irregular degree of land use plaque morphology increased, complexity of landscape increased. In the last ten years, the fractal of woodland decreased and trend to stable; fractal dimension of cultivated land and grassland increased in different degree; boundaries showed complex and the stability of landscape plaque decreased.
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