湖泊阻隔对鱼类群落的影响——以保安湖为例

CONNECTIVITY LOSS IN LAKE ON FISH COMMUNITIES ——A CASE STUDY OF BAO’AN LAKE

  • 摘要: 为探讨湖泊内部阻隔引发的生态问题, 阐释鱼类群落聚合对湖泊内部阻隔的响应, 研究选取长江中游典型阻隔湖泊保安湖为研究对象, 于2019—2020年夏季和秋季对其肖四海湖区(完全阻隔)、扁担塘湖区(半阻隔)、桥墩湖区(半阻隔)和主体湖区的鱼类群落结构进行了调查, 应用单因素方差分析、置换多元方差分析和非度量多维尺度等多重统计方法分析了湖区间鱼类群落组成和多样性的差异。结果表明, 完全阻隔湖区肖四海鱼类群落结构发生了明显变化, 其种类数(15±3)种显著低于半阻隔湖区(22±3)种和主体湖区(23±3)种, P<0.05, 鱼类丰度高而生物量低, 物种丰富度指数、Shannon指数和Simpson指数显著低于主体湖区(P<0.05), 功能丰富度指数、功能分散度指数和功能均匀度指数也显著较低(P<0.05); 而半阻隔湖区鱼类群落结构与主体湖区无显著性差异。置换多元方差分析和非度量多维尺度分析也显示出完全阻隔湖区鱼类群落与半阻隔湖区和主体湖区鱼类群落具有显著性差异(P<0.05), 半阻隔湖区与主体湖区无显著性差异。研究发现湖泊内部水文阻隔对鱼类群落组成也有着重要影响, 恢复湖泊内部水文自由连通对湖泊生态管理和生物多样性保护有着重要作用。

     

    Abstract: Hydrological connection plays an important role in maintaining biodiversity and ecosystem function. In order to explain the effect of internal hydrological disconnection and response of fish communities, we selected a typical hydrological disconnection lake in middle reaches of Yangtze River-Bao’an Lake as the study object. Field sampling was conducted in Xiaosihai Lake (part of Bao’an Lake, complete disconnection), Biandantang Lake (part of Bao’an Lake, semi-disconnection), Qiaodun Lake (part of Bao’an Lake, semi-disconnection) and the main lake in both summer and autumn from 2019 to 2020. We compared and analyzed the differences of fish communities and functional diversity among those lakes using the multiple statistical methods. Result showed that the fish community structure in the complete disconnection lake had been changed significantly, which species number (15±3) was significantly lower than that in the semi- disconnection lake (22±3) and the main lake (23±3; P<0.05); abundance increased while the biomass decreased; the species richness index, the Shannon index and the Simpson index were significantly lower; and functional richness index, functional dispersion index and functional evenness index were also significantly lower the other lakes (P<0.05). However, the fish community structure in the semi-disconnection lake had no significant difference with that in the main lake. The Permutational multivariate analysis of variance and non-metric multidimensional scaling analysis also showed that the fish community in the complete disconnection lake significantly distinguished from the semi-disconnection lakes and the main lake (P<0.05), while there was no significant difference between the fish communities of semi-disconnection lakes and main lake was closer. Our study found that the internal hydrological disconnection in lake also has an important impact on the composition of fish communities, and restoring the free hydrological connectivity within lake was crucial to ecological management and biodiversity conservation.

     

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