昆明城市化过程中土地利用变化及景观梯度分异

LAND USE CHANGE AND GRADIENT DIFFERENTIATION OF LANDSCAPE IN KUNMING DURING ITS URBANIZATION

利用Landsat MSS/TM/ETM＋（1974、1992、2000和2006年）4期遥感影像,应用3S（GIS,RS,GPS）技术提取昆明市土地利用信息,分析土地利用变化、景观梯度分异及方向性差异。研究表明1974~2006年3个时间段内,昆明有林地呈现减少—增加—减少的趋势,建设用地扩张速度逐年增加,城市扩张致使耕地大幅度减少;草场退化,荒草地逐年减少;裸地从1992年以来呈增加趋势,果园保持增加趋势。通过设置经过市中心的SW-NE、SE-NW两条空间样带和围绕市中心的20个梯度样带分析,1974~2006年建设用地向东北方向和东南方向扩展尤其突出,同时期SW-NE样带比SE-NW样带受城市化影响更为明显;另外,4个景观指数（斑块密度PD、最大斑块指数LPI、面积加权分形维数FARC_AM、香农多样性指数SHDI）出现变化的起始梯度圈带均逐渐外移,且变化趋势明确地反映了景观破碎化程度形成一个从城市中心向外围逐渐减小的空间梯度。

Applying the Landsat MSS/TM/ETM ＋ images from 1974, 1992, 2000, 2006 and using 3S （i. e. GIS, RS, GPS） technology to extract land use of Kunming, then analysis the land use change, landscape gradient differentiation and directional difference. The results show that the forest presents decline - increase - de- cline from 1974 to 2006 in Kunming. Construction land increased dramatically because of urban sprawl, while cul- tivated land decreased greatly. The waste -grassland reduced due to grassland degradation year by year. Bare land shows an increasing trend after 1992, and the orchard maintained steady growth during these years. Through set- ring two spatial transects （ SW - NE and SE - NW） and twenty gradient zones crossing the urban center, it illus- trates that SW - NE is more profoundly influenced by urbanization than the other. On the other hand, construction land spread prominently to northeast and southeast. The gradient zone number lagged, where four landscape met- rics （Patch Density - PD, Largest Patch Index - LPI, Area - weighted Mean Fractal Index - FARC_ AM, Shannon＇ s Diversity Index -SHDI） starts to change. Change trends of the metrics shows a spatial gradient of de- creasing from urban center to outwards.