禁渔后西凉湖鱼类物种和功能多样性时空格局及其与水环境因子的关系

SPATIAL-TEMPORAL PATTERNS OF FISH TAXONOMICAL AND FUNCTIONAL DIVERSITY IN XILIANG LAKE AND THEIR RELATIONSHIP WITH WATER ENVIRONMENTAL FACTORS AFTER FISHING BAN

为解析禁渔后西凉湖鱼类群落组成、结构与多样性格局,探明影响鱼类多样性的关键环境因子,于2020年11月和2021年4月在西凉湖开展了鱼类群落与环境因子调查,共设置15个样点,分布于西-西凉湖(XLH1-8)和东-西凉湖(XLH9-15)。结果表明秋季与总氮、叶绿素a和高锰酸盐指数呈正相关,西-西凉湖与总磷和浊度呈正相关。本次调查共采集鱼类31种,隶属6目8科26属,其中鲤形目最多(24种),占77.4%。优势种为似鱎、?、鲫和红鳍原鲌,其中似鱎为主要优势种。非度量多维尺度排序分析(NMDS)结果表明,西凉湖鱼类群落结构具有显著的季节和空间差异(P<0.05)。在秋季,东-西凉湖的Shannon-Wiener指数、Simpson指数和Pielou指数均显著高于西-西凉湖(P<0.05);Margalef指数显著高于西-西凉湖(P<0.05);在秋季,东-西凉湖的功能丰富度指数显著高于西-西凉湖(P<0.05);功能分散度指数显著高于西-西凉湖(P<0.05)。Pearson相关性分析结果表明, Shannon-Wiener指数、Simpson指数、Pielou指数和Margalef指数与功能丰富度指数(r=0.66、r=0.61、r=0.50和r=0.83)、功能分散度指数(r=0.93、r=0.89、r=0.89和r=0.70)呈显著正相关(P<0.05),即物种多样性增加,占据的功能空间越大。冗余分析结果显示,总磷是驱动西凉湖鱼类物种和功能多样性的关键环境因子。研究为禁渔后长江流域湖泊鱼类资源恢复和生态系统修复提供了科学依据,为今后湖泊生态保护政策提供了参考。

In order to examine the composition,structure and diversity of fish assemblages in Xiliang Lake after fishing ban and identify key environmental factors affecting fish diversity,the investigation of fish assemblages and environmental factors was conducted in Xiliang Lake in November 2020 and April 2021,with 15 sample sites distributed in West-Xiliang Lake(XLH1-8)and East-Xiliang Lake(XLH9-15).The results showed that autumn was positively correlated with total nitrogen,chlorophyll a and chemical oxygen demand index,and West-Xiliang Lake was positively correlated with total phosphorus and turbidity.The results showed that a total of 31 fish species were collected belonging to 6 orders,8 families,and 26 generas,among which the Cypriniformes(24 species)accounted for 77.4%.Toxabramis swinhonis,Hemiculter leucisculus,Carassius auratus,and Cultrichthys erythropterus were the dominant species,and Toxabramis swinhonis was the most dominant species.The results of Nonmetric Multidimensional Scaling indicated the significant seasonal and spatial differences in fish community structure in Xiliang Lake(P<0.05).Shannon-Wiener index,Simpson index and Pielou index of East-Xiliang Lake were significantly higher than that in West-Xiliang Lake in autumn(P<0.05),and Margalef index was significantly higher than that in West-Xiliang Lake(P<0.05);Functional richness index of East-Xiliang Lake was significantly higher than that in West-Xiliang Lake in autumn(P<0.05),and functional dispersion index was significantly higher than that in West-Xiliang Lake(P<0.05).Pearson correlation analysis exhibited that Shannon-Wiener index,Simpson index,Pielou index and Margalef index were significantly and positively correlated with functional richness index(r=0.66,r=0.61,r=0.50 and r=0.83)and functional dispersion index(r=0.93,r=0.89,r=0.89 and r=0.70;P<0.05).This result indicated that higher taxonomical diversity may contribute more functional space in fish assemblages.The results of the Redundancy Analysis indicated that total phosphorus were the key environmental factors driving fish species and functional diversity.This study provides a scientific basis for the recovery of fish resources and ecosystem restoration of lakes in the Yangtze River basin after the fishing ban,and provides a reference for future lake ecological protection policies.