Effect of road development on landscape pattern in Xishuangbanna

In recent years,the ecology system in Xishuangbanna was severely influenced by the construction and development of roads,which caused fragmentation of biological habitat and degradation of ecosystem.In order to investigate the internal relation between the roads network and landscape pattern,and also quantitatively estimate the effect on landscape caused by different classes of roads in Xishuangbanna since 1976,we assessed the effect of roads development on landscape pattern based on four land-use maps(1976,1988,1999,2010),which were interpreted from the Landsat MSS/ TM/ ETM imageries.The assessment was made by buffer analysis tool in ArcGIS 9.3,moving split-window techniques(MSWT) was also employed.The results showed that the fragmentation of landscape increased by increasing roads density.The percentage of natural landscape areas decreased by increasing distance to the roads,while the percentage of artificial landscape areas(i.e.rubber plantation,farmland,building site) increased at the same time.The distance between the roads and affected landscape showed significant difference among three main class roads as: the second grade roadsthe first grade roadsthe third grade roads.The affecting distance increased faster in the first grade roads.The percentage of the four-type landscape areas affected by the roads increased by increasing density of the roads,the second grade roads exerted the greatest influence on the area of affected landscape.The largest increasing extent was demonstrated in the first grade roads both in the affected areas and distance from the roads during the past 34 years.