金沙江下游水电开发对浮游植物多样性及群落构建的影响机制  

Mechanisms of the impact of hydropower development on phytoplankton diversity and community assembly in the lower Jinsha River

作　　者：周心怡 周雄冬 张家豪 翁楚彬 徐梦珍 ZHOU XinYi;ZHOU XiongDong;ZHANG JiaHao;WENG ChuBin;XU MengZhen(State Key Laboratory of Hydroscience and Engineering,Beijing 100084,China;Department of Hydraulic Engineering,Tsinghua University,Beijing 100084,China;Institute of Hydrobiology,Chinese Academy of Sciences,Wuhan 430072,China;National Engineering Research Center for Inland Waterway Regulation,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]水圈科学与水利工程全国重点实验室,北京100084 [2]清华大学水利水电工程系,北京100084 [3]中国科学院水生生物研究所,武汉430072 [4]重庆交通大学国家内河航道整治工程和技术研究中心,重庆400074

出　　处：《中国科学:技术科学》2025年第3期540-552,共13页Scientia Sinica(Technologica)

基　　金：国家自然科学基金联合基金项目(批准号:U2240207,U2243222)和国家自然科学基金青年科学基金项目(批准号:52309094)资助。

摘　　要：金沙江下游水电开发极大改变了原有的山区自然激流环境,形成片段化、缓流甚至静止的水库生境,水生生态系统发生显著变化.以往研究基于传统的采样调查和形态学鉴定方法揭示了该河段浮游植物多样性与群落结构的基本特征,但对水电开发影响下的多样性变化、群落构建机制及影响因素缺乏研究.本研究以向家坝238 km河段为研究区域,基于eDNA方法对浮游植物进行了系统采样,分析其多样性、群落结构及功能特征,探讨向家坝水电站运行影响下浮游植物多样性及群落构建机制.结果表明,水动力条件对向家坝浮游植物α多样性的影响最为显著,α多样性在空间上呈现“坝下干流>坝上支流>坝上干流”的梯度分布,共现网络的结构、种间互作强度及鲁棒性沿此梯度增强,表征浮游植物群落在面对环境变化和干扰时抵抗力的增强.α多样性水平在大坝处发生突变,尤其是Chao1和PD指数由上游随着接近大坝而显著下降模式转变为下游随着远离大坝而下降模式.水动力和水质条件变化是引起浮游植物β多样性变化的主要驱动因素.向家坝河段尺度上,β多样性由周转组分驱动,表征随机过程对群落构建起主要作用,支流物种通过扩散和环境筛选影响干流群落.大坝处的β多样性显著高于上、下游,以嵌套组分为主,表征环境筛选等确定性过程在该局部河段起关键作用.本研究有助于理解水电开发影响下河流生态系统的演变与适应机制,为山区河流保护与开发协调可持续发展提供了科学依据.Hydropower development in the lower Jinsha River has drastically altered the natural torrent landscape of this mountain river.This has led to fragmented,slow-flowing,and even stagnant reservoir habitats,resulting in significant changes in aquatic ecosystems.Although previous studies have provided foundational insights into the diversity and community structure of phytoplankton in this reach based on traditional sampling surveys and morphological identification methods,there is a lack of research on the changes in diversity,community assembly,and the influencing factors under the impact of hydropower development.In this study,phytoplankton were sampled along the 238-km Xiangjiaba section using the environmental DNA method.The diversity,community structure,and functional characteristics of phytoplankton were analyzed,and the diversity and community construction mechanism of phytoplankton under the impact of the Xiangjiaba Hydropower Station were explored.The results revealed that hydrodynamic conditions were the most significant factor influencingαdiversity.Phytoplanktonαdiversity showed a spatial gradient following“mainstream downstream of the dam>tributaries upstream of the dam>mainstream upstream of the dam”.Along this gradient,the structure,interspecies interactions,and robustness of the co-occurrence network increased,demonstrating the enhanced resistance of the phytoplankton community in the face of environmental changes and disturbances.Notably,there was a significant shift inαdiversity at the dam location.In particular,the Chao1 and PD indices showed a significant downward trend from upstream to the dam,shifting to a decreasing pattern downstream when moving away from the dam.Changes in hydrodynamics and water quality were the primary drivers of shifts inβdiversity.At the Xiangjiaba reach scale,phytoplanktonβdiversity was primarily driven by the turnover component,showing stochastic processes as the main mechanism of community assembly.Tributary species influenced the mainstream community through d

关 键 词：金沙江 梯级水电开发 浮游植物 环境DNA 群落构建 

分 类 号：Q94[生物学—植物学]