近30年来三江源地区土地覆被与宏观生态变化特征  

The characteristics of land cover and macroscopical ecology changes in the source region of three rivers on Qinghai-Tibet Plateau during last 30 years

作　　者：邵全琴[1] 赵志平[1,2] 刘纪远[1] 樊江文[1] 

机构地区：[1]中国科学院地理科学与资源研究所,北京100101 [2]中国科学院研究生院,北京100039

出　　处：《地理研究》2010年第8期1439-1451,共13页Geographical Research

基　　金：国家973计划项目(2009CB421105);中国科学院西部行动计划项目(KZCX2-XB2-06-03);国家科技支撑计划项目(2006BAC08B00)

摘　　要：利用1970年代中后期MSS图像和1980年代末、2004年以及2008年三期TM图像并结合野外调查,获得三江源地区四期土地覆被空间数据集,提出了土地覆被转类指数和土地覆被状况指数,以表征该区域生态变化的趋势。通过计算土地覆被转类途径和幅度、土地覆被转类指数和土地覆被状况指数,分析青海三江源地区1970年代中后期以来土地覆被时空变化特征及其反映的宏观生态状况变化。结果表明:三江源地区近30年平均土地覆被状况指数为38.20,土地覆被状况为4级,其中黄河流域最好,其次为澜沧江流域,长江流域最差;三江源地区土地覆被转类,在1970s～1990s和1990s～2004年两个时段,均主要以高生态级别向低生态级别转移为主,2004～2008年时段,主要以低生态级别向高生态级别转移为主;由土地覆被状况指数变化率和土地覆被转类指数,可以反映出近30年来三江源地区土地覆被和宏观生态状况,总体上经历了变差(1970s～1990s时段土地覆被状况指数变化率Zc为-0.63,土地覆被转类指数LCCI为-0.58)—显著变差(1990s～2004时段Zc为-0.94,LC-CI为-1.76)—略有好转(2004～2008时段Zc为0.06,LCCI为0.33)的变化过程。这一变化过程前、中期主要受到气候变化和草地载畜压力共同驱动的影响,后期则叠加了生态建设工程的驱动作用。Based on field investigations we obtained four phase land cover spatial data sets by interpreting MSS images of the mid-and late 1970s and three phase TM images of the late 1980s,2004 and 2008 in the Three Rivers＇ Source Regions.We defined the relation between land cover type and ecological grade,land cover change index and land cover condition index to characterize the trends of land cover and macroscopical ecological changes in this region.By calculating the direction and extent of land cover change,land cover change index and land cover condition index,we analyzed temporal and spatial characteristics of land cover change and macro ecological condition change in the source region of three rivers on the Qinghai-Tibet Plateau since the mid-and late 1970s.The results showed that the average land cover condition index of the Three Rivers＇ Source Region was 38.20,being the fourth grade in the last 30 years.The Yellow River basin had the best land cover condition,followed by the Lancang River basin,and the Yangtze River basin had the worst.Land cover type with high ecological grade transforming to that with low grade was the main phenomena during the 1970s to 1990s and the 1990s to 2004.Land cover with low grade transforming to that with high grade was the main phenomena during 2004 to 2008.Indicated by land cover condition index change rate and land cover change index,land cover and macro ecological condition degenerated（7090 period Zc-0.63,LCCI-0.58）-obviously degenerated（9004 period,Zc-0.94,LCCI-1.76）-slightly meliorated（0408 period,Zc 0.06,LCCI 0.33）.This course was jointly driven by climate change,grassland stocking pressure and implementation of ecological construction project.

关 键 词：三江源 土地覆被状况指数 转类指数 转类途径 

分 类 号：F301[经济管理—产业经济] F205