长江源区河流及典型湖泊丰水期水质与鱼类群落分析

为加强长江源区水生态研究,于2017年丰水期调查了长江源区5个湖泊、5条河流的水质和鱼类资源状况,并研究了其空间格局。水质综合指数(WQI)计算结果显示,长江源区WQI范围为41~87,评价等级介于差到良好之间,大部分采样点的水质评价等级为一般,其中,班德湖的水质评价等级为良好。主成分分析结果显示,长江源区河流、淡水湖、微咸水湖和咸水湖的水质指标呈现出明显的空间差异。河流水质呈现出较高的总磷、总氮、硝态氮、总悬浮物和浊度,淡水湖呈现出较高的水温、溶解氧及WQI,咸水湖呈现出较高的总碱度、总硬度、盐度、电导率和pH。长江源区鱼类多样性较低,共调查到5种鱼类,包括小头高原鱼(Herzensteinia microcephalus)、裸腹叶须鱼(Ptychobarbus kaznakovi)、斯氏高原鳅(Triplophysa stoliczkae)、细尾高原鳅(Triplophysa stenura)和梭形高原鳅(Triplophysa leptosoma)。对长江源区水质因子和鱼类群落进行皮尔逊相关分析显示,长江源区鱼类群落主要与水质指标中的浊度和盐度有关。为切实保护好长江源区水质和鱼类资源,建议加强科研监测,建立长江源区水生态数据库,建立土著鱼类种质资源库和基因库,预防和控制外来鱼类的引入,同时要加强鱼类栖息地保护。

Water Quality and Fish Assemblage Patterns in Rivers and Typical Lakes in the Source Region of the Yangtze River During the Wet Period

This paper investigated the water quality and fish resource status of five lakes and five rivers in the source region of the Yangtze River during the wet perioid in 2017,and studied their spatial patterns.The results showed that the water quality index (WQI) of the source region ranged from 41 to 87,making the evaluation grade between poor and good.Most sampling sites were fair,and the Bande Lake was good.Principal components analysis showed obvious spatial differences of water quality among rivers,freshwater lakes,micro-salt lakes and salt lakes in the region.For example,the water quality of rivers showed higher total phosphorus,total nitrogen,nitrate nitrogen,total suspended matter and turbidity,while freshwater lakes showed higher water temperature,dissolved oxygen and WQI.And total alkalinity,total hardness,salinity,conductivity,and pH were higher in the saltwater lakes.Fish diversity was very low in the region.Only five fish species were captured,these were Herzensteinia microcephalus,Ptychobarbus kaznakovi,Triplophysa stoliczkae,Triplophysa stenura and Triplophysa leptosoma.Pearson correlation analysis found that fish assemblage had a strong correlation with water turbidity and salinity in the source region.To effectively protect water quality and fish resources in the source region of the Yangtze River,we suggest strengthen scientific research and monitoring,establish the hydro-ecological database as well as the germplasm bank and gene bank of indigenous fish species,prevent and control the introduction of exotic fish species,and protect the fish habitats.