西双版纳地区公路两侧土地利用变化格局特征

根据西双版纳地区1976、1988和2003年三期LandsatMSS/TM/ETM影像解译的土地利用数据,运用Arc-G IS软件的缓冲区分析方法,分析该区内主干公路两侧土地利用变化的时空格局。结果如下:27 a间,与整个西双版纳州相比,主干公路两侧的土地利用强度更大、增长速度更快。公路两侧的土地利用转化主要表现为由林地向橡胶园和茶园转变,林地锐减,橡胶园迅速增加,林地是橡胶园的最主要来源。主要地类的面积在一定范围表现出与距公路距离的相关关系,距公路越近,林地面积百分比越小,橡胶园、建筑用地和水田面积百分比越大。土地利用变化也表现出明显的公路效应,距离公路越近,林地减少的速度、橡胶园增加的速度越快;随着距离的增加,林地向橡胶园的转化面积逐渐减小。土地利用变化的公路效应深度表现出不断扩展的趋势:1976年为公路两侧5 km,1988年为7 km,2003年达11 km。

Land Use and Land Cover Change Analysis on Main Roadsides in Xishuangbanna

Road affects the environment around them in many aspects,including removing original land cover,fragmenting habitat,altering landscape structure and function,and increasing disturbances from human beings.In this paper,we studied the land use and land cover change(LUCC) on the two sides of the main roads in Xishuangbanna from 1976 to 1988,and from 1988 to 2003 based on land use maps of 1976,1988,2003,which were interpreted from the Landsat MSS/TM/ETM imageries,with the buffer analysis tool in ArcGIS 8.The results showed that,1)During last 27 years,compare with Xishuangbanna,the land use intensity on roadsides is higher and increased faster;2) The transition among different types of land use and land cover is,rubber plantation and tea garden increased obviously while forestland decreased dramatically,and the forest losing was mainly attribut able to the expansion of rubber plantation;3)The correlation index between the land-use distribution and the distance apart from the main road is high in certain range: the area percentage of the forest is smaller when nearer to the road,while the percentage areas of rubber plantation,the tea garden,the build-up and the paddy fieldare larger at the same time;and vice versa;4) The road effects to land-use changes are observably: the decline in forestland cover,and the increase in rubber plantation,both decreased with increasing distance from the road;with the distanceapart from the road increasing,the area of rubber plantation converted from the forest reduces gradually.5) Based on the land use degree comprehensive index,the distances from the mainroads of significant land use and land cover change was defined:in 1976,it was 5 km;in 1988,7 km;and it rose to 11 km in 2003.