关键词: 生态安全, 环境变化, 绿洲, 黑河中下游

Abstract: On the basis of assessing the ecological security for the five oases of the middle and lower Heiher River in the middle 1980s and at the beginning of 2000s, the paper analyzes the ecological security change of these oases. The integrated assessing results of the oases ecological security are reduced from the middle to the lower reaches of Heiher River in the middle 1980s and at the present. The present state of ecological security declines more than that of 1980s. The dropping range also increases from the middle to the lower reaches. Compared with those of 1980s, water security and land security drop obviously, but social economic security rises a little within the three subsystems. Under the background of macroscopical climate change, the cultivated land increases and oasis area enlargement in the middle reaches makes more imbalance between supply and demand of water resource, which has caused certain negative effect on the ecological environment of the oasis in lower reaches. And it is the very important reason that causes the oasis in the lower reaches diminishing, the oasis systematic area of the whole basin atrophying, and the stability declining. In order to realize the ecological security and sustainable development of the Heiher basin, it must strengthen allocation of the water resource in the whole basin and make basin comprehensive management.

Key words: ecological security, environment change, oasis, the middle and lower Heiher River