金沙江一期工程蓄水前后绥江段鱼类群落多样性特征

为探索流域梯级水电开发对鱼类群落多样性影响,于2011年(蓄水前)和2015年(蓄水后)对金沙江下游绥江断面进行渔业资源调查,分析鱼类群落结构特征。结果表明,绥江段共计采集鱼类60种,隶属于5目12科,其中长江上游特有鱼类12种。蓄水前以瓦氏黄颡鱼(Pelteobagrus vachelli)、圆口铜鱼(Coreius guichenoti)、光泽黄颡鱼(Pelteobagrus nitidus)为优势种类;蓄水后以草鱼(Ctenopharyngodon idellus)、鳙(Aristichthys nobilis)、鲢(Hypophthalmichthys molitrix)为优势种类。与蓄水前相比,鱼类群落Margalef丰富度指数、Shannon-Weiner多样性指数、Pielou均匀度指数均呈现下降趋势,但无显著性差异(P0.05)。根据生态类群分析,静水缓流型鱼类由蓄水前54%增加到蓄水后的71%,河道洄游型鱼类从39%减少到20%,江湖洄游型鱼类蓄水前后变化不大。丰度生物量比较曲线显示,蓄水前绥江段鱼类群落未受到干扰,而蓄水后受到严重干扰。库区蓄水后总生物量有明显增加趋势,但优势种类趋于小型化、种类结构单一化。为科学保护金沙江下游流域鱼类生物多样性,建议成立鱼类保护区、开展梯级生态调度和加强流域环保预警研究等措施。

VARIATION CHARACTERRISTICS OF FISH BIODIVERSITY IN SUIJIANG SECTION BEFORE AND AFTER IMPOUNDMENT OF FIRST PHASE OF JINSHA RIVER HYDROPOWER PROJECT

In order to understand the ecological effects of drainage basin cascade hydropower development on fish communities biodiversity,fisheries resources survey were carried out in the Suijiang section,lower reaches of Jinsha River,during 2011 before impoundment of first phase of Jinsha hydropower project and 2015 after impoundment of hydropower project.Fish community biodiversity variation characteristics were analyzed.Results showed that there were 60 fish species in the Suijiang reaches according to our fourth investigation on fisheries resources,which belonged to 5 order,12 family,and there were 12 upper Yangtze River endemic fish species in total species.Before the impoundment of Jinsha River first phase hydropower project,lotic fish species such as Pelteobagrus vachelli,Coreius guichenoti,Pelteobagrus nitidus were the dominant species while preferring to the reservoir environment species,such as Ctenopharyngodon idellus,Aristichthys nobilis,Hypophthabnichthys molitrix,were major species after the impoundment of Jinsha River hydropower project.Compared to the fish species biodiversity before the impoundment,Margalef richness index,Shannon-Weiner diversity index,and Pielou evenness index were sharply decreased,but there were no significant differences (P＞0.05).According to the analyses on the fishes ecological groups,limnophilic fish species were increased from 54％ to 71％,river-river migratory fish species were decreased,and river-lake migratory fish species had no change after the impoundment of Jinsha River hydropower project.Abundance/biomass comparison curves showed that fish communities were affected sharply after the impoundment.And the total fishing biomass were increased in the whole reservoir after the impoundment because of the increasement of water primary productivities while the dominant species have smaller body type and simplification trend.In order to scientifically protect the fisheries resources in the Jinsha River,establishing fish natural protected area,carrying out ecological operation,and strengthening the study of the early warning on environmental protection in river basin were suggested as the useful measures.