The landscape change and assessment of the eco-environment quality in the lower and middle reaches of Tarim River

本文以塔里木河下游绿色走廊为主体的塔里木河中下游河流廊道区域为研究对象，这是一个处于塔里木河流域尺度上的河流廊道景观区域，在干旱区景观生态格局与功能中具有独特之处。近几十年来由于气候变化和人类活动影响，塔里木河中下游的生态环境发生了很大的变化，特别是塔里木河中下游以天然植被为主的生态系统和生态过程因人为对自然水资源时空格局的改变而受到严重影响。因此，对塔里木河中下游的景观格局变化及生态环境质量评价的研究具有一定意义。应用GIS技术和景观分析软件Fragstats，以1980年、1990年和2000年Landsat5/7卫星TM/ETM数字图像，植被、土壤类型图为基础，分析了研究区土地利用/土地覆被结构、各景观要素类型变化的幅度和速度，并选取稳定性指数、分形维数、多样性指数、优势度指数和破碎化指数来分析1980年～2000年景观格局的变化。同时，利用马尔可夫模型分析了各景观类型之间的转化特征，并对未来情况进行预测。在生态环境质量评价方面，本文从生态脆弱性的角度，制定合适流域特点的生态环境质量评价指标体系，为各评价指标的空间属性，规定其权重值由评价指标影响空间范围的大小来决定。实现了研究区不同区段的生态环境质量定量评估，为流域生态生态环境保护提供科学依据。最后，本文在土壤退化与景观格局之间关系的研究方法方面做了初步的探讨。In this paper, the river-corridor regions in the middle and lower reaches of Tarim River, dominated by the Green Corridor in the lower reached of the Tarim River, are selected as the study objects, which is of significance for understanding the regional landscape ecological characteristics and for approaching the general plan of the regeneration of landscape ecology. During the recent decades, due to the climate change and human beings’ activities, the environment degeneration has taken place, especially the ecosystem constituted natural vegetation resources. Therefore, it means a lot to do the research of landscape change and assessment of the eco-environment quality. Based on GIS techniques and land-use data of the middle and lower reaches of Tarim River in 1990 and 2000, which were interpreted by landsat TM/ETM remote sending images, the landscape structure, changes of landscape types, the dynamic of landscape types were studied carefully. And using the stability index, fractal dimension, landscape diversity index, dominance index, and fragmentation, landscape pattern of the middle and lower reaches of Tarim River were analyzed. Based on the synthetic analysis, the trend of land use has been forecast with the Markov model in the middle and lower reaches of Tarim River. Based on the analytic hierarchy process and specialists’ ideas, the assessment of the eco-environment quality system is set up. To give prominence to the spatial attribute of each assessment index the weight values were determined by the magnitude of special range that was influenced by assessment index. Then the evaluation on the eco-environment quality in the study area in the middle and lower reaches of Tarim River are carried out. At last, the paper makes a primary discussion on the measure of the relation between the landscape and soil degeneration