安庆七里湖湿地鱼类群落多样性特征及其影响因子

Fish community diversity and its relationship with environmental variables in Qili Lake wetland in Anqing

为探究水位、水温等因子对七里湖鱼类群落结构及多样性的影响,本研究于2019—2020年分别在高水位(丰水期)、平水位(平水期Ⅰ、Ⅱ)和低水位(枯水期)对七里湖展开4次鱼类调查,同步进行水域生态环境采样。本次调查共采集鱼类47种,隶属4目10科36属,鲤科鱼类占65.96%,60%以上为淡水定居性鱼类,主要栖息在中上层水域,以浮游生物食性鱼类为主,其中似鳊(Pseudobrama simoni)为第一优势种。丰水期和平水期鱼类平均物种数分别为35和33种,均显著多于枯水期的22种(P<0.05);丰水期平均渔获数量为1008尾,显著高于平水期、枯水期的662尾、594尾(P<0.05),平均渔获重量不同水期间无显著差异(P>0.05)。丰水期鱼类多样性和丰富度指数均显著高于枯水期(P<0.05),但优势度指数仅0.14,显著低于枯水期(P<0.05)。聚类分析结果显示,枯水期鱼类物种组成为类群Ⅰ,丰水期与平水期为类群Ⅱ,且类群Ⅰ与类群Ⅱ存在极显著性差异(P<0.01)。总体上,丰水期鱼类群落多样性高于平水期和枯水期,水位、水温、总磷和透明度是影响鱼类群落结构重要环境因子(P<0.05)。

To explore the effects of water level and temperature on fish community structure and diversity in Qili Lake,four surveys were carried out at high water level(wet season),flat water level(normal period I,II)and low water level(dry season)during 2019-2020,with environmental factors being measured.A total of 47 species were recorded in the survey,belonging to 4 orders,10 families,and 36 genera.Cyprinids accounted for 65.96%of total species richness.More than 60%of the species were freshwater sedentary fishes,mainly dwelling in the upper and middle waters.The community was dominated by plankton-feeding fishes,with Pseudobrama simoni as the predominant species.The mean fish species richness in wet season and normal season was 35 species and 33 species,respectively,which were significantly higher than the 22 species in dry season(P<0.05).The average abundance of fish caught in the high water period was1008,which was significantly higher than that of 662 fish and 594 fish in the low water period(P<0.05).The average weight of fish caught in different water periods showed no variation(P>0.05).The diversity index and richness index in the wet season were significantly higher than those in the dry season(P<0.05),but the dominance index was significantly lower than that in dry season(P<0.05).The results of cluster analysis showed that fish species composition in the dry season was classified into the group I,and that in the wet season and the normal season was classified into the group II,with a significant difference between both groups(P<0.01).In general,the diversity of fish community in the high water season was higher than that in the normal water season and the dry water season.Water level,water temperature,total phosphorus,and transparency were important environmental factors driving fish community structure(P<0.05).