中文摘要：

通过野外实地调查和相关资料分析研究发现,近50年来塔里木河下游地区经历了一个生态系统逐步退化的过程,主要表现为地表水文解体、地下水位下降、水质恶化、植被衰败、风沙灾害加剧等5个方面。分析指出,塔里木河下游地区的环境恶化已经给当地人民的生产生活带来了灾难,影响了社会经济的可持续发展。借助有关统计资料和实地调研资料,对流域社会经济发展水平、产业结构、区域资源分配与下游地区来水量减少、生态退化之间的关系进行了分析探讨,发现塔里木河流域区域之间水资源分配不均和流域内社会经济发展水平低下、产业结构不合理是导致流域下游地区水资源紧张、生态退化的根源。最后,从系统的观点和人文的角度出发对流域社会经济发展、水资源利用、生态环境建设之间的相互作用机理机制做了探讨。

英文摘要：

The lower reaches of the Tarim River are famous for their strategic position and prominent ecological problems. Based on field surveys and statistical analysis, this paper describes ecosystem degradation in the lower reaches of the Tarim River according to five aspects： surface water resource shortage, decline of water table, deterioration of water quality, decline of vegetation and sandstorm disasters. We also describe the way that ecosystem degeneration brought disaster to the local people. For example, people had to abandon more than 1. 16 × 104 hm^2 of farmland in the 1990s because of desertification and drought. Furthermore, it threatens ecosystem security and sustainable development in the upper and middle reaches of the Tarim River. Much research has been done on ecosystem restoration in the lower reaches of the Tafim River. Most of it focused on changes in hydrology and methods of vegetation regeneration. However, it is very important to study the ecosystem degradation using systematic methods to identify the human mechanisms of desertification. With statistical data on population, economy, society and water resource usage for all of the Tarim River basin, we studied the mechanisms interrelating socio-economic development, water resource usage and environmental construction, and identified the essential reasons for water resource tensions and ecosystem degeneration. In the Tafim River Basin, more than 65% of water resources were used for farming, and more than 50% of this water was lost through evaporation in channels and reservoirs. The human population near the Akesu fiver, Yarkant river and Hetian river increased from about 130 × 10^4 in the 1950s to 405 × 10^4 in 2005, however, the production per water unit did not increase accordingly, so farmland increased about 91 × 10^4 hm^2 in the last 50 years. Because of low-efficiency water resource usage and the agriculture-oriented economy, almost all of the water was used for agriculture. The average runoff in the headstream of the Tarim River in the