南亚热带典型水库浮游生物群落的嵌套结构及互作关系

Nestedness and Interspecific Interactions Within the Plankton Community in Reservoirs of Southern Subtropical China

为了解我国南亚热带水库浮游生物群落特征及驱动因素,加强水生态环境管理与保护,于2022年枯水期(3月)和丰水期(7、8月)分别在我国南亚热带地区5座大中型水库采集浮游植物和浮游动物样品,并测定相应水体理化指标,结合零和模型及网络分析等方法分析浮游生物的群落组成、嵌套结构、互作网络及环境影响。结果显示:(1)丰水期pH、水温和浊度显著高于枯水期,氨氮含量显著低于枯水期(P<0.05);(2)浮游植物丰水期共调查到8门299种(属)、枯水期8门274种(属),浮游动物丰水期4类群89种、枯水期4类群106种;(3)浮游植物、浮游动物实际分布矩阵的嵌套性指标(12.57、25.32)与随机分布矩阵(18.04±8.32、29.31±3.46)间存在显著性差异(P<0.05),调查水库浮游生物均表现出明显的嵌套结构,有利于群落稳定;(4)浮游生物群落间存在互作关系,且具有明显水期特征,丰水期浮游生物网络更加复杂紧密和稳定,能更加迅速应对环境干扰,丰水期浮游生物群落主要受CODMn、pH、水温、浊度影响,枯水期浮游生物群落主要受浊度、CODMn和总磷影响。控制有机物及营养盐输入、降低浊度是调控水库浮游生物群落的关键手段。

In this study,we explored the characteristics and driving forces of plankton community structure in subtropical reservoirs in China.Our aim was to provide theoretical support for managing and protecting the aquatic environment,consequently maintaining the health of reservoir ecosystems and achieving a balance between ecological protection and resource utilization.Five medium-large subtropical reservoirs of southern China were selected for study,and phytoplankton and zooplankton samples were collected during the dry season(March)and wet season(July and August)in 2022.Phys-icochemical water quality parameters were measured simultaneously at each sampling site.The null model,network analysis and other methods were combined to analyze the composition,nestedness,inter-action and factors influencing the plankton community.Results show that:(1)The pH,water temperature(WT)and turbidity were significantly higher in wet season than in dry season,and the content of ammo-nia nitrogen(NH3-N)was significantly lower in wet season(P<0.05).(2)A total of 299 phytoplankton species(genera)from 8 phyla were detected in wet season and 274 species(genera)from 8 phyla were de-tected in dry season.For zooplankton,89 species from 4 taxa were detected in wet season and 106 species from 4 taxa were detected in dry season.(3)There were significant differences between the nestedness in-dicators of the actual distribution matrix of plankton(12.57,25.32)and the random distribution matrix(18.04±8.32,29.31±3.46)(P<0.05),indicating that the phytoplankton and zooplankton clearly display nestedness in subtropical reservoirs that is beneficial for maintaining plankton community stability.(4)There were interspecific interactions within the plankton community,characterized by distinct hydroperiods.The planktonic interaction network was more complex,compact and stable during wet season,allowing a more rapid response to environmental disturbances.The plankton communities were primarily influenced by chemical oxygen demand(CODMn),pH,WT and turbidity in wet season,and by turbidity,CODMn and total phosphorus(TP)in dry season.In conclusion,controlling the input of organic matter and nutrients and reducing turbidity are key to regulating the reservoir plankton communities.