不同营养类型水库大型底栖动物的群落结构特征及其水质评价

The community structure of macrozoobenthos and water quality assessment on different trophic types of reservoirs

2006～2007年对湖北省4座不同营养类型水库的大型底栖动物群落结构和多样性进行周年研究,并进行了水质评价。共采集到底栖动物39种,其中寡毛类14种、水生昆虫19种、软体动物6种。以金沙河的底栖动物种类最多,达24种,其次为徐家河19种,道观河和桃园河各10种。4座水库优势种类各异,金沙河为多毛管水蚓(Aulodrilus pluriseta)、隐摇蚊(Cryptochironomussp.)、多足摇蚊(Polypedilumsp.);徐家河为瑞士水丝蚓(Limnodrilus helveticus)、前突摇蚊(Procladiussp.);桃园河为多毛管水蚓(Aulodrilus pluriseta)、长跗摇蚊(Tanytarsussp.);水质污染比较严重的道观河水库优势种类为霍甫水丝蚓(Limnodrilushoffmeisteri)、大红德永摇蚊(Tokunagayusurika akamusi)。各库底栖动物年平均密度和生物量分别为:金沙河316.8ind.m-2,1294.3mg.m-2;道观河318.2ind.m-2,430.7mg.m-2;徐家河330.3ind.m-2,517.4mg.m-2;桃园河209ind.m-2,325.3mg.m-2。TN、TP、COD平均含量变幅分别为0.392～1.018、0.011～0.042、3.505～9.166mg.L-1;采用理化分析、Goodnight-Whitley指数、Shannon-Wiener指数、Margalef指数、Simpson指数、Pielou均匀度指数对水库的水质进行了综合评价,结果表明:金沙河水库属中营养型;徐家河和桃园河属中-富营养型;道观河水库属富营养型。对水库主要的物理化学因子与寡毛类、水生昆虫、软体动物密度,以及各类底栖动物之间进行矩阵分析,发现水生昆虫与水深呈负相关关系,随着水深的增加,其密度和种类下降,水深超过10m,下降的幅度更明显;寡毛类有从属于TN和TP含量的趋势,TP变化对底栖动物的影响更大;寡毛类、水生昆虫、软体动物三者之间无相关性。

The community structure and biodiversity of macrozoobenthos were investigated and water quality was assessed with the four different trophic types of reservoirs in Hubei province from 2006 to 2007.A total of 39 taxa were identified,among which 14 were oligochaetes,19 were aquatic insects,and 6 were molluscs.Jinshahe Reservoir had 24 species of zoobenthos,Xujiahe Reservoir had 19,and Daoguanhe and Taoyuanhe Reservoir had 10.Dominant species were different from reservoirs.They were Aulodrilus pluriseta,Cryptochironomus sp.,Polypedilum sp.in Jinshahe reservoir,Limnodrilus helveticus,Procladius sp.in Xujiahe reservoir,and Aulodrilus pluriseta,Tanytarsus sp.in Taoyuanhe reservoir.However,Limnodrilus hoffmeisteri and Tokunagayusurika akamusi were the dominant species in Daoguanhe Reservoir,where the water was polluted seriously.The average density and biomass of zoobenthos were 316.8ind·m^-2 and 1294.3mg·m^-2 in Jinshahe Reservoir,318.2ind·m^-2 and 430.7mg·m^-2 in Daoguanhe Reservoir,330.3ind·m^-2 and 517.4mg·m^-2 in Xujiahe Reservoir,209ind·m^-2 and 325.3mg·m^-2 in Taoyuanhe Reservoir.The average TN,TP and COD were 0.392-1.018mg·L^-1,0.011-0.042mg·L^-1 and 3.505-9.166mg·L^-1,respectively.Water quality was assessed using both physical and chemical analyses,including Goodnight-Whitley index,Shannon-Wiener index,Margalef index,Simpson index and Pielou index.These analyses indicated that Jinshahe Reservoir was mesotrophic,Xujiahe and Taoyuanhe Reservoirs were meso-eutrophic and Daoguanhe Reservoir was eutrophic.Comparative analysis of the five indices suggested that the criteria of the Shannon-Wiener and Margalef indices need correction and improvement for water quality assessment of reservoirs,despite they are widely used Moreover,the Simpson index was found to be unsuitable for water quality assessment in deep reservoirs.Matrix analyses indicated that the density and species of aquatic insects declined with an increase of water depth and that oligochaetes were affected by TN and TP.The influence of TP on zoobenthos was more obvious than that of TN.No correlations were found among species of zoobenthos.