塔里木河下游生态输水对植被和地下水位的影响

由于近50a来人类不合理的资源开发,造成塔里木河下游的生态环境问题日趋严峻.为拯救下游绿色走廊和改善下游环境,于2000年7月始,实施了塔里木河下游应急生态输水工程,水流到达台特玛湖本文根据2a来在塔里木河下游的监测结果,通过对下游天然植被的一些生态指标的变化和输水后地下水位变化等资料进行对比分析,发现随着输水工程的进行,距输水河道一定范围内地下水位升高明显.相应地,下游植被的生态响应也很显著,沿河岸许多种草本植被又重新出现,而一些耐旱乔、灌木随着生境的改变,长势也出现明显好转,主要表现在植被盖度、植物多样性指数和丰富度指数的提高以及胡杨冠幅的加大.同时,研究结果表明,截止2002年9月,在塔里木河下游中段,生态输水对地下水影响范围为800m,天然植被恢复的范围为700m.由于环境条件的差异,在不同区段的影响范围不一样,总体上表现为由上而下逐步递减的趋势.

Effect of Translating Water on Vegetation at the Lower Reaches of Tarim River

Due to human irrational resource exploit in recent 50 years, many environment problems have appeared at the lower reaches of Tarim River, the environment degradation of this region became seriously. In order to restore green corridor and improve the environment at the lower reaches of Tarim River, the project of transporting water to the lower reaches of Tarim River was carried out from June 14, 2000 and the water reached Taitema lake finally. After two years' monitoring and analyzing in this region, it was found that the ground water level went up and much extremely degraded vegetation was restored. Some xerophytic arbor and bush restored obviously with the change of habitat. Correspondingly, the groundwater level, vegetation coverage, diversity of biology, the species richness and crown of Populus euphratica all changed. By the end of September 2002, the result showed that the respond range of the ground water level was 800m from the river, and the respond range of vegetation was not beyond 700m at the middle part of lower reaches of Tarim River. Due to the different environmental factors in different parts at the lower reaches of Tarim River, the response range changed accordingly. In general, the respond range became smaller and smaller from the upriver part to downstream part.