塔里木河下游典型区景观生态质量评价

Landscape Ecological Quality Evaluation of the Typical Region in the Lower Reaches of Tarim River

近20年来,由于人类对水资源利用的不合理,塔里木河下游生态环境持续恶化,大西海子水库以下河段自1974年以来至2000年全部断流。本文选取卡拉～台特马湖段呈东南向分布的狭长地带为典型区,以2000年的TM影像为数据源,在RS和GIS技术的支持下提取了土地利用程度及植被类型因子,结合地下水位对塔里木河下游典型区进行了景观生态质量综合评价。研究将典型区按景观生态质量高低分为好、一般、较差、差和极差五个等级,结果表明:质量优的景观多是河道附近呈斑块状分布的人工绿洲,质量差的景观是塔里木河下游典型区的主体,景观质量较差的景观面积占典型区的98.91％,主要分布在距离河道比较远的地区和英苏以下地段。以上研究结果可为生态治理规划提供科学依据。

Located in Xingjiang of the Northwestern China, Tarim River is the longest inland river of China. Owing to the improper use of water resources, the ecological environment in the lower reaches of Trim River has degraded greatly in recent 20 years. The 320 km - long riverbeds below Daxihaize reservoir have been dried up since 1974. Taking the section between Kala and Taitema Lake as a typi-cal region of Tarim River, this paper comprehensively evaluated the landscape ecological quality. Three evaluation indices were selected, i. e. ground water table, land use and vegetation. The information of both land use and vegetation came from TM image taken in 2000. With the support of RS and GIS techniques, landscape ecological quality in the typical region was divided into five levels. The spatial distribution of landscape ecological quality in each level was also obtained. The result showed that landscape ecology in bad quality was the main body of the typical region. The area of landscape in level 3, 4 and 5 occupied 98. 91 % of the total area. They were usually far away from the riverbeds and mostly distributed in the lower reaches below Yingsu. While those in good quality scatter along the river and were usually artifitial oasis. This research provided a scientific foundation for the planning of ecological management in this region.