洞庭湖水生态环境的演变与保护对策

Hygrophilous Ecological Environment Succession and Countermeasure of the Dongting Lake

依据多年监测和调查资料,分析了洞庭湖生态环境的演变,提出了水生态环境的保护对策。从1949年至今洞庭湖容积减少了约43%,湖泊萎缩严重,调蓄能力下降,湖区共发生洪涝灾害39次。20世纪90年代,湖泊水质污染加剧,总磷污染指数增加了7.04倍;1999年藻类数量最高达22万个/L,水体富营养化呈发展趋势;湿生物种减少,一些湿地动植物已经很少见到;底栖动植物的密度虽然变化不大,但其组成从1982年以水生昆虫及幼虫为主,到1996年变化为以软体动物为主,正表明了水体富营养化的加剧。三峡水库运行后,水沙条件的变化,对洞庭湖水生态环境将会产生相应的影响。目前要加强洞庭湖综合整治,进行湖泊生态恢复与重建,以维持洞庭湖资源的可持续利用与发展。

According to the monitoring and survey for many years,the succession of the hygrophilous ecological environment in the Dongting Lake was analyzed,and the countermeasures about the ecological environment protection were proposed. The cubage of the Dongting Lake has reduced about 43% since 1949. As the lake gradually withered, the ability of its storage declined. The disasters were up to 39 in total. In the 1990s ,the pollution of the water quality has aggravated. The TN pollution index has increased by 7.04 times. The maximum number of alga has reached 220 000 per liter ,the eutrophication of the water continued to show a development tendency. The species of the wet living beings decreased,some wet living beings are seldom seen. The main consistence of the amphibious animals and plants has changed from aquatic insects and larva in 1982 to mollusk in 1996 ,but its density has not changed ,it is just illustrate the aggravation of eutrophication of the water. The operation of the Three Gorges lead to the changes of the water and sand conditions, which influenced the ecological environment of the Dongting Lake. So as to maintain sustainable utilization and development,the comprehensive control of the Dongting Lake must be strengthened ,as well as ecological rebuilding.