洞庭湖大型底栖动物群落结构和水质评价

Macrozoobenthic community structure and bioassessment of water quality in Lake Dongting,China

2014年4个季度对洞庭湖大型底栖动物进行调查,共记录底栖动物4门7纲58种,其中寡毛类7种,软体动物28种,水生昆虫19种,线虫1种,蛭类2种,钩虾1种.洞庭湖底栖动物平均密度为187.4 ind./m^2,软体动物是最主要的类群,平均密度为88.7 ind./m^2,占总密度的47.3%,寡毛类和水生昆虫的密度分别为24.1和27.8 ind./m^2,分别占总密度的12.9%和14.9%.河蚬(Corbicula fluminea)、铜锈环棱螺(Bellamya aeruginosa)、苏氏尾鳃蚓(Branchiura sowerbyi)、指突隐摇蚊(Cryptochironomus digitatus)和钩虾(Gammaridae sp.)为洞庭湖的优势种.典范对应分析表明,水温和溶解氧是影响洞庭湖底栖动物分布的关键环境因子.采用Shannon-Wiener多样性指数和BI生物指数对洞庭湖各样点的水质状况进行评价,总体上评价结果分别为轻污染和良好,结果表明二者具有一定的差异,结合洞庭湖各样点的综合营养状态指数可以看出,BI指数的评价更加适合洞庭湖水质评价.

Macrozoobenthos were quarterly investigated in Lake Dongting in 2014,a total of 58 species belonging to 4 Phylums and 7 Classes were recorded,including 7 Oligochaeta,28 Mollusca,19 Insecta,1 Nematoda,2 Hirudinea and 1 Gammaridae. The average density of macrozoobenthos was 187. 4 ind. / m^2,of which mainly represented by mollusks. The density of mollusks,oligochaetes and aquatic insects was 88. 7,24. 1 and 27. 8 ind. / m^2,accounted for 47. 3%,12. 9% and 14. 9% of total density,respectively. The dominant species were Corbicula fluminea,Bellamya aeruginosa,Branchiura sowerbyi,Cryptochironomus digitatus and Gammaridae sp.. Canonical correspondence analysis showed water temperature and dissolved oxygen were highly correlated with macrozoobenthic community structure. Shannon-Wiener diversity index and Hilsenhoff＇s Biotic Index（ BI） were calculated to assess the water quality of Lake Dongting,the evaluation result was light pollution and good respectively. The results of two indices were different to a certain extent,combined with ∑TLI,BI methods was more suitable for bioassessment in Lake Dongting.