长湖浮游植物优势种季节演替及生态位分析

SEASONAL SUCCESSION AND ECOLOGICAL NICHE ANALYSIS OF THE DOMINANT SPECIES OF PHYTOPLANKTON IN CHANGHU LAKE

  • 摘要: 为查明长湖浮游植物优势种群落结构特征及季节演替规律, 于2015年4月至2016年1月对长湖浮游植物群落结构及相关环境因子进行了调查, 同时利用典范对应分析法(CCA)进行浮游植物优势种与环境因子的相关性分析。结果表明: 本次调查共鉴定出浮游植物优势种共14种, 其中扭曲小环藻(Cyclotella comta)、小球藻(Chlorella vulgaris)和梭形裸藻(Euglena acus)是4个季节的共有优势种。生态位宽度(Niche width)变化范围为1.002—2.377, 其中夏季小球藻最高, 广生态位种类以富营养化水体常见指示种小球藻、扭曲小环藻、两栖颤藻(Oscillatoria amphibia)等种类为主。平均边缘指数(OMI)变化范围为0.25—3.71, 其中小于1的物种共12种。耐受指数(TOI)变化范围为0.13—3.35, 夏季两栖颤藻最高。生态位重叠值的变化范围为0.02—0.93, 其中秋季扭曲小环藻和梭形裸藻的重叠值最高。选取7个环境因子与浮游植物优势种进行CCA分析发现: 夏季微小平裂藻(Merismopedia tenuissima)、两栖颤藻、四尾栅藻、扭曲小环藻以及梭形裸藻与TN和TP呈正相关性。综合(优势种群落结构特征、生态位参数及其与环境因子相关性)分析表明, 长湖浮游植物优势种群落结构特征及其相关生态位指数与物种形态结构、生活方式和生境状况等密切相关, 反映出浮游植物各季节优势种对生境资源的不同利用能力。与2012年研究结果比较, 冬季裸甲藻数量明显增多, 成为冬季优势种, 且广生态位优势种数量也有所增加, 表明长湖仍处于浮游植物种类组成单一、稳定性较差的富营养化状态, 且富营养化程度有加重趋势。

     

    Abstract: To find out the community structure characteristics and seasonal succession of dominant species in Changhu Lake, phytoplankton and environmental factors were investigated from April, 2015 to January, 2016. The results showed that 14 dominant species of phytoplankton were identified and Cyclotella comta, Chlorella vulgaris and Euglena acus were common species in the all seasons. Niche indexes and the characteristics of the community structure of dominant species were analyzed. The niche breadth index varied from 1.002 to 2.377 for Chlorella vulgaris in summer. Wide niche breadth species, such as Chlorella vulgaris, Cyclotella comta and Oscillatoria amphibian, were considered common indicator species in eutrophic water. The other indexes, such as the outlying mean index (OMI) (0.25—3.71), tolerance index (TOI) (0.13—3.35) and niche overlaps (0.02—0.93), were determined. The correlation between 7 environmental parameters and dominant species analyzed by canonical correspondence analysis (CCA) showed that there were significant positive correlations between the TN, TP and several dominant species, such as Merismopedia.tenuissima, Oscillatoria amphibian, Scenedesmus quadricauda, Cyclotella comta and Euglena acus, in summer. Comprehensive analysis showed that the characteristics of community and niches were significantly correlated with the morphology, lifestyle and habitat of dominant species of phytoplankton. There were also different abilities to utilize the habitat resources of dominant species in each season. Compared with the date in 2012, Gymnodinium aeruginosum was considered a dominant species in winter, and the density increased. The number of wide niche breadth species increased at the same time. The results showed that Changhu Lake remaind in the eutrophic state and that the degree of eutrophication tended to increase.

     

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