陕北农牧交错带土地沙漠化景观格局动态变化

利用1986、1993及2003年3期LandsatTM遥感影像,借助地理信息系统技术,分析了陕北农牧交错带1986—2003年土地沙漠化景观格局的演变.结果显示,该区近17年来沙漠化面积减少了206655.2hm2,景观结构上斑块数量减少,破碎化程度减轻.沙漠化程度明显下降,沙漠化主导类型已由严重沙漠化转变为中度和轻度沙漠化.1986—2003年沙漠化景观整体上向西南和东北方向扩展,严重威胁着西南和东北部黄土丘陵区的生态安全.

Dynamic changes of land desertification landscape pattern in agriculture and pasturage interlaced zone of northern Shaanxi

By using the 1986,1993 and 2003 Landsat TM images and with the help of GIS,the dynamic changes of land desertification landscape pattern in agriculture and pasturage interlaced zone of northern Shaanxi in 1986-2003 were analyzed.The results showed that in the past 17 years,the desertification area in the zone decreased by 206 655.2 hm2,with the patches in landscape structure reduced and fragmentation abated.Fortunately,the desertification degree decreased obviously,and moderate and light desertification took the leading position.From 1986 to 2003,the spatial centroid of desertification landscape patches expanded southwestward and northeastward,giving serious threat to the ecological safety of the southeast and northeast loess gully and hilly areas.