Analysis of Socio-Economic Factors Related to Ecosystem Degradation in the Lower Reaches of the Tarim River in the Last 50 Years
近50年来塔里木河流域下游生态系统退化社会经济因素分析

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 hm2 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 Tarim 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 Tarim 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 river, Yarkant river and Hetian river increased from about 130×104 in the 1950s to 405×104 in 2005, however, the production per water unit did not increase accordingly, so farmland increased about 91×104 hm2 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 last 50 years was about 183×108 m3, and it increased slightly in the 1990s. However water resources in the lower-reaches of the Tarim River decreased annually over the last 50 years. The average runoff in Qiala was less than 1.5×108 m3 for the last 5 years. Too much water was consumed in the upper and middle reaches of the Tarim River, causing desertification in the lower reaches.