近20 a塔里木河干流区土地利用变化特征

基于GIS技术及景观生态学原理，利用塔里木河干流区4期（1990年、2000年、2005年和2008年）土地利用遥感影像解译数据，研究近20 a塔里木河干流区土地利用的变化特征。结果表明：塔里木河治理后的10 a干流耕地面积增加了1.03×10⁵ hm²，耕地动态度增加较大，盐碱地面积增加了7.13×10⁴ hm²，较治理前增速呈减缓态势；草地面积约减小了4.91×10⁵ hm²，林地、水域面积呈先增加后减小的趋势，但两者动态度减小。沙地、盐碱地的动态度减小，表明塔里木河综合治理基本抑制了干流区盐碱地、沙地面积增加的速度。同时，土地利用类型转移的方向主要是草地、林地、耕地、沙地之间的相互转化。塔里木河综合治理引起干流区水资源的再分配，对耕地、林地和盐碱地面积的变化影响较大；从各景观类型指标分析，聚集度指数明显降低，说明景观破碎度和连通性降低；而多样性指数和均匀度指数增加，表明区域景观异质性增加，稳定性增大。这些变化可能导致土壤表层积盐，沼泽地面积减少。本研究将有助于对综合治理工程的实施效果进行综合评估。

Analysis on Land Use Change in the Mainstream Area of the Tarim River in Recent 20 Years

This paper analyzed the land use change under natural and artificial flooding before and after implementing the water redistribution project in the mainstream area of the Tarim River based on four sets of land use data in 1990,2000,2005 and 2008.The results showed that the land use change was obvious after implementing the project.The area of farmland was enlarged by 1.03×10⁵ hm² in recent 20 years,and the dynamic degree of land use was highly increased after implementing the project,the area of alkaline land was enlarged by 7.13×10⁴ hm²,area of steppe was reduced by about 4.91×10⁵ hm²,the areas of forests and waters were enlarged at first and then reduced in recent 20 years,but the dynamic degree of land use was decreased,these indicated that the land use types were changed frequently from 1990 to 2008.Enlargement tread of alkaline land and sand land was restricted to some extent after implementing the water redistribution project.The mutual transition of land use types occurred mainly in steppe,woodland,farmland and sand land.At landscape level,the Contagion Index (CONTAG),Landscape Division Index (DIVISION),ShannoJP8]n’JP]s Diversity Index (SHDI) and SimpsoJP8]n’JP]s Diversity Index (SIDI) were calculated.The results showed that the landscape fragmentation and connectivity were decreased,but the diversity index and evenness index were increased,which revealed that the heterogeneity and stability of landscapes were increased.These changes may result in a salt accumulation in topsoil and the reduction of wetland.The study results could be applicable in assessing the effect of implementing the water redistribution project.