江苏省不同营养状况湖泊底栖动物群落结构与多样性比较

A Comparative Study on Macrobenthic Community Structure and Diversity in Different Trophic Status Lakes of Jiangsu Province

为了解江苏省湖泊底栖动物群落结构和多样性并研究其对水环境质量变化的响应,于2012年春秋两季对江苏省16个湖泊51个采样点湖泊底栖动物群落结构与多样性以及湖泊综合营养状态指数进行调查,分析水质指标与底栖动物指数间Pearson相关关系。结果表明,江苏省16个湖泊营养状态指数范围为35.5~66.4,其中约81.2%的湖泊处于轻度-中度富营养状态,表明水质从好到中度污染;湖泊底栖动物优势种为寡毛类的霍甫水丝蚓(Limnodrilus hoffmeisteri),优势度为13.0%;香浓多样性指数(Shannon-Wiener diversity index)范围为0.00~2.20,级别范围由极贫乏到较丰富状态,表明水质污染程度从重度到轻度污染。从全省尺度看,水质评价结果与生物学(香浓多样性指数、Pielou均匀度指数和Biotic Index(BI)指数)评价结果存在一定差异。与历史数据相比,江苏省湖泊底栖动物清洁敏感物种减少甚至消失,总体群落结构趋于小型化。16个湖泊水体总氮和总磷与底栖动物密度呈显著负相关,而综合营养状态指数与底栖动物指数(香浓多样性指数、Pielou均匀度指数和BI指数)间关系不显著。上述研究结果表明综合营养状态指数无法完全客观反映湖泊水生态健康状况,因此需要综合水质、水文、水生生物、生境状况等因素发展新的评价指标体系。

Lake eutrophication has resulted in loss of biodiversity and degradation of ecosystem function. To investigate the structure of the benthic macroinvertebrate community and explore their responses to changes of water quality, samples were collected at 51 sites in 16 lakes of Jiangsu Province in Spring and Autumn of 2012. The relationships between water environmental variables and benthic macroinvertebrate indicators were examined using Pearson correlation analysis. The results showed that STSI of the 16 lakes ranged from 35.5 to 66.4. 81.2% were nearly eutrophic or super-eutrophic. The benthic macroinvertebrate communities were dominated by Limnodrilus hoffmeisteri of oligochaetes with a dominance value of 13.0%. The Shannon diversity index ranged from 0.00 to2.20,which suggested that the benthic macroinvertebrate community diversity in 16 lakes of Jiangsu Province was from quite deficient to rich status. Compared to historical data, sensitive taxa of macroinvertebrate communities decreased or even disappeared; the dominance of small size taxa increased greatly. Total density of benthic macroinvertebrate animals was significantly negatively correlated with total nitrogen and total phosphorus. However, no significant correlations were detected between trophic index and benthic macroinvertebrate indices. Our results suggested that synthesized trophic state index can＇t reflect the ecological health of benthic community. Therefore, a new evaluation system should be established according to water quality, hydrology, aquatic organisms, habitats and other factors in the future.