【摘要】 为了解洱海全湖底栖动物的组成及分布规律,2012年3月对其进行全面的调查,在设置的42个样点中共采集到底栖动物1108头,隶属于14个分类单元,其中优势种为霍甫水丝蚓(Limnodrilus hoffmeisteri)、分离底栖摇蚊(Benthalia dissidens)和似羽摇蚊(Chironomus cf.plumosus),相对丰度分别为57.0%、20.3%和12.0%。洱海全湖底栖动物的平均密度为549.4 ind·m-2,平均生物量为8.68 g·m-2。聚类和非度量多维尺度(NMDS)分析揭示,洱海底栖动物群落呈现北、中、南三个生物群系的分布格局。基于Shannon-Wiener指数、Goodnight指数和BPI指数的生物评价显示,洱海水质整体处于中污染状态,且南部污染程度较北部严重。对比历史数据可知自上世纪80年代以来,洱海底栖动物群落结构逐步发生改变,优势种由原来的苏氏尾鳃蚓(Branchiura sowerbyi)和分离底栖摇蚊转变为耐污能力更强的霍甫水丝蚓和似羽摇蚊,群落单调且优势度高,显示洱海水质发生了衰退。更多还原

【Abstract】 Zoobenthic assemblage was examined for the 42 sampling sites designed for the March 2012 survey in Erhai Lake. Among the 1108 benthos examined, 14 taxa were identified. The dominant species were Limnodrilus hoffmeisteri, Benthalia dissidens and Chironomus cf. plumosus, which accounted for 57.0%, 20.3% and 12.0% of total abundance, respectively. The average zoobenthos density was 549.4 ind·m-2 and the average biomass was 8.68 g·m-2 for the whole lake. Cluster analysis and non-metric multidimensional scaling(NMDS) analysis revealed that 3 subcommunities different in species composition occupied the north, south and middle parts of the lake, respectively. Bioassessment of water quality based on Shannon-Wiener diversity index(H’), Goodnight biotic index(GI), and biological pollution index(BPI) indicated that the overall water quality was in intermediate organic pollution with the south part more severe than the north part. Compared with historical data, the once dominant species in 1980s(e.g., Branchiura sowerbyi and Benthalia dissidens) were gradually replaced by those more tolerant species found in this study(e.g., Limnodrilus hoffmeisteri and Chironomus cf. plumosus), suggesting that the water quality had undergone a deterioration.更多还原