摘要
利用策勒绿洲 195 6、1990和 1998年 3个不同时期的遥感数据 (航片、TM和SPOT)进行配准、解译与分类处理 ,比较分析绿洲 4 0多年来的动态变化 ,并从自然和人为因素两个方面探讨绿洲变化的原因。结果表明 ,从 195 6年到 1998年策勒绿洲西北部的景观格局发生了显著变化 ,绿洲面积增加了近 2 0 % ;林地的分布明显改变 ;河道发生显著位移 ,据实地调查大约向北移动 4 0 0m。对 1990年TM与 1998年SPOT分类数据 ,用FRAGSTATS软件计算景观格局指数并比较分析 ,发现研究区的绿洲、绿洲 荒漠交错带、荒漠和沙丘 4种景观类型发生了明显的变化。绿洲面积增加而斑块数减少了近一半 ;交错带面积减少而斑块数增加了 35 % ;荒漠面积减少而斑块数增加了 6 0 % ;沙丘面积基本没有变化但斑块数减少了 2 0 %。绿洲变化的总体趋势是人工绿洲的面积增大而绿洲 荒漠交错带的面积明显减少 ,同时整个绿洲的破碎度增加而连通性降低 ,绿洲的稳定性和自我调节的功能下降。
Environmental change of oases in the arid regions of China is a subject of recent concern. Although many of the changes have been recorded qualitatively through the use of comparative photography and historical reports, little quantitative information has been available on regional scale. Geographical information systems (GIS) and remote sensing (RS) technologies provide the basis for developing landscape composition and pattern indicators as sensitive measures of large-scale environmental change and thus may provide an effective and economical method for evaluating the condition of oases in relation to human and natural disturbances. This paper discusses the dynamic changes of the Qira oasis over a 40 year period by using 3 types of imagery data: aerial photographs (1956), TM (1990) and SPOT (1998). Remote sensing data were interpreted and classified using ARC/INFO and ERDAS software and landscape indices of satellite imagery were calculated using FRAGSTATS 3.0 software. The change in the spatial extent of landscape forms and vegetation types around Qira oasis was analyzed by comparing SPOT satellite image from 1998 with aerial photographs from 1956. The results showed that the area covered by vegetation of the Qira oasis increased by nearly 20% from 1956 to 1998, but the distribution of vegetation distribution changed greatly and the river bed shifted about 400 m. Dune and desert encroachment was successfully combated near the oasis border but increased in extent at the outward border of the surrounding vegetation. The area covered with Populus trees was smaller in 1956 than today due to some new forests established in 1977 north of the oasis. Subfossil wood and leaf remnants of Populus euphratica found in the surrounding areas must have originated from forests destroyed before 1956. The main Qira river has shifted its bed significantly northward and developed a new furcation with a large new bed in 1986. The natural river dynamics are not only an important factor forming the oasis landscape pattern but
出处
《植物生态学报》
CAS
CSCD
北大核心
2004年第3期369-375,共7页
Chinese Journal of Plant Ecology
基金
国家自然科学基金项目 ( 2 0 2 0 46)
欧盟基金资助项目(IC18CT98_0 2 75 )
