滇池水环境退化与区域内物种多样性的丧失

Environmental degradation and loss of species diversity in Dianchi Lake

本文论述了滇池草海的物种多样性指数由20世纪50年代的2.70(ShannonˉW iener Index)降到90年代的0.29;滇池外海在20世纪50年代末,湖水面积90%以上为海菜花群落、马来眼子菜群落等,70年代仅占20%弱,20世纪90年代末的水生植物覆盖率不及3%;分析了藻类的种群优势度向着蓝藻种群优势度不断增加的方向发展,浮游动物的多样性增加,大型底栖无脊椎动物物种结构趋向单一化,鱼类多样性指数由1957年的1.81降为1997年的0.11,滇池的物种多样性指数由20世纪60年代的1.08降到90年代的0.67,认为滇池水环境退化与物种多样性丧失呈双向恶化效应,物种多样性重建是滇池生态恢复的重要指标。

Dianehi Lake, a large shallow lake in Yunnan - Guizhou Plateau, southwest of China, lies in 102°42′E and 25°04′N. It consists of Grass Lake and Outer Lake, which is under the jurisdiction of Kunming City. It is 1885 m above sea level, with a length of 40 km and an average width of 10.5 km. Its surface area is 298.4 km^2 ,with an average depth of 4. 1 m and water capacity of 1.29 billion m^3 （ 1886.5 m above sea level）. This article bears on the study of environmental degradation and loss of species diversity in Dianchi Lake. Dianchi Lake once enjoyed the prestige of ＂Flower Sea＂. However, having been heavily polluted by industrial and agricultural waste water in the recent three decades, the water environment in Dianchi Lake was degenerated, and the hydrophyte was sharply destroyed and furthermore the loss of species diversity was typical. The dominant blue-green algae have increased whereas green algae have decreased rapidly. Zooplankton species diversity has enhanced and the species structure of large benthos has become simple. Species diversity offish decreased from 1.81 in 1957 to 0.11 in 1997. From the 1960s to the 2000s, the species diversity index in Grass Lake declined from 2.70 （Shannon - Weiner Index） to 0.29 and that in Dianchi Lake declined from 1.08 to 0.67 during the 1970s - the 2000s . This article expounds the dynamic mechanism between the environmental degeneration and the loss of species diversity from the 1960s to the 2000s in Dianchi Lake. The dynamics shows that environmental change in Dianchi Lake can provide some theoretical bases for ecological prevention and warning, environmental protection and restoration in lakes.