Community Structure of Macrozoobenthos and Its Relationship with Environmental Factors in Lake Hongze
洪泽湖大型底栖动物群落结构及其与环境因子的关系

Lake Hongze is the fourth largest freshwater lake in China,however,there is limited information on the macrozoobenthos in the lake.Surveys on macrozoobenthos of the lake were carried out seasonally from May 2010 to February 2011,to investigate the community structure and its major driving environmental factors.A total of 14 taxa were identified based on 80 quantitative samples from 20 sampling sites,including oligochaetes(5 species,35.7% of the total),chironomids(3,21.4%) and molluscs(6,42.9%).The dominant species were Corbicula fluminea(dominance Y = 0.18),Limnodrilus hoffmeisteri(0.09),Chironomus plumosus(0.07),Limnodrilus hoffmeisteri(0.06) and Bellamya aeruginosa(0.06),respectively.The average total density and biomass were(45.45 ±7.38) ind/m2 and(52.43 ± 12.04) g/m2 respectively,mainly consisted of oligochaetes (6.96 ± 2.41) and(0.60 ± 0.18) ],chironomids (13.76 ± 2.87) and(2.28 ± 0.71) ]and molluscs (24.80 ± 6.20) and(49.55 ± 11.94) ].The annual values of Shannon-Wiener,Margelef and Pielou’s indices were 2.69,1.10 and 0.71,respectively,without obviously seasonal changes.Among 14 environmental factors,the results of redundancy analysis accounted for 35% of macrozoobenthos community variance,and Monte Carlo’s test showed that nitrate nitrogen,total nitrogen and COD(F = 2.181-3.277,P < 0.05) were the key factors that significantly influenced the distribution and community structure of macrozoobenthos.