摘要: |
根据1957-1997年期间对洱海水体进行的历次综合研究结果分析.由污染引起的氮、磷等营养元素含量升高促进藻类生长繁殖,40年来其密度和生物量上升近10倍;近5年的变化尤为明显,一度出现以螺旋鱼腥藻 (Anabaena spiroides Klebahn)为主的"水华".银鱼(Neosalanx taihuensis Chen) 移植等渔业生产活动导致浮游动物在近10年锐减,现在的密度仅是1957年的1/8水体有机污染的增加,有利于苏氏尾鳃蚓 (Branchiura sowerbyi Claparedi)、摇蚊科幼虫等生长,大型底栖无脊椎动物的密度上升了一个数量级;水生高等植物在50-80年代呈扩展趋势,而近期则由稳定趋于衰退,受过度捕捞、鱼类移植、水位急剧下降等影响,洱海鱼类经历了4次较大的变动,即 50-60年代以土著鱼类为主、70年代以波氏栉鯱鱼(Ctenogobius cliffordpopei(Nichols))为主、80年代以鲫鱼(Carassius auratus(Linnaes))为主、90年代以银鱼和鲤鱼为主;洱海特有的 7种土著鱼类,如大理裂腹鱼 (Schizothorax taliensis Regan)等几乎绝种。 |
关键词: 洱海 生物群落 演替 |
DOI:10.18307/1999.0312 |
分类号: |
基金项目:中国科学院湖沼专项基金 |
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On the Succession of Aquatic Communities in Erhai Lake |
WU Qing-long, WANG Yun-fei
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Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing 210008
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Abstract: |
Erhai Lake is located in the west of Yunnan Province. It plays an important role in the Dali regional economic development. However, with the development of economy and increase of population in the region, the impacts of human activity on ecological environment of Erhai Lake have been strengthened. Based on the investigations on Erhai Lake from 1996 to 1997 and data of the past 40 years' research, this paper gives a detailed analysis on the succession of its aquatic communities. From 1957 to 1997, the density and biomass of phytoplankton increased nearly 10 times and this change was more intensive in the last 15 years. The dominant species have also changed greatly. The non-pollution resistant species such as Ceratium hanclelli Skuja, Psephone-ma aenigmaticum Skuja, Lyngbya Limnetica Lemm. have disappeared, while the species which can indicate eutrophication such as Anabaena spiroides Klebahn and Microcystis fios-equae (Wit-tr.) Kirch increased. Because of the transformation of “Four Domestic Fishes” and ice fish, the density and biomass of zooplankton have been decreasing.However, organic pollution resulted in the rise of density and biomass of limnitic oligochaeta and chironomid larvae. The density of zoobenthos has increased nearly 8 times. There are two apparent variation periods of aquatic vegetation. From 1957 to 1985, distribution of aquatic vegetation tended to expand. From 1985 to 1997, it tended to reduce because of unreasonable utilization. With the transformation of extra fishes, rapid decrease of water level, over capture of fish resources etc., the fish community of Erhai Lake has changed greatly. In the 1950s and 1960s, the fish community was dominated by aboriginal fishes. In the 1970s, the fish Ctenogobius cliffordpopei was dominant. In the 1980s, the dominated fish turned to Carassium auratus.In the 1990s, the ice fish and common carp become main economic fish of Erhai Lake.fishes tend to die out. The fish of Schizothorax taliensis has disappeared. |
Key words: Erhai Lake aquatic communities succession |