密云水库浮游动物多样性格局

对密云水库6个代表性生境的浮游动物做了每月一次的采样调查.记录到浮游动物106种(新记录39种),其中清洁水和贫营养指示种增多.春季的螺形龟甲轮虫、夏季的长额象鼻溞优势明显,秋、冬季无明显优势种.物种数、个体密度和物种多样性均表现为夏季高而冬春季低的规律.单月物种数最高58种(8月),最低16种(5月).个体密度变动于21.93～149.53 ind/L,年均74.88 ind/L±39.97(S.D.).物种多样性(H)变动于0.97～2.91,年均2.06±0.74;均匀度(J)变动于0.30～0.74之间,年均0.60±0.16.各月份物种数、个体密度和物种多样性都以浅水区最高、河口区次之、深水区最低,但位点间差异不显著.多元线性回归结果显示密云水库浮游动物物种多样性特征受水温和溶解氧影响显著(F=72.94,P=0.001),与其它水环境参数相关不大.浮游动物群落结构的稳定性和演替趋势表明水库水质状况良好,富营养化因子未对水库生态系统产生健康威胁.

Biodiversity pattern of Zooplankton in Miyun Reservoir

We conducted a monthly professional investigation on Zooplankton diversity in Miyun Reservoir through March to December of 2010.Totally 106 species,consisting of 21 Protozoa,50 Rotifera,18 Cladocera and 17 Copepoda were detected,among which 39 were new records to this water.Results showed that species associating with clean water increased in number and densities.Dominant species changed frequently from month to month,with the first predominance of Keratella cochlearis and Bosimina longirostris in spring and summer respectively,but no species was predominant in the other seasons.Species richness,individual density and species diversity indexes changed frequently in the reservoir,with peak values in summer and lowest values in winter and spring.Species richness fluctuated between 16 in May and 58 in August.Individual density changed from 21.93 to 149.53 ind / L with a annual mean of 74.88 ± 39.97（S.D.） ind / L.The index of species diversity（H） in every month varied from 0.97 to 2.91,with a annual mean of 2.06 ± 0.74,and index of evenness（J） changed similarly between 0.30 and 0.74 in each month with a annual mean of 0.60 ± 0.16.These seasonal changes of zooplankton characteristics related significantly to the regularly changed water temperature and dissolved oxygen（F = 72.94,P = 0.001）,but not significantly to any other environmental factors.Spatial analyses indicated that the richness and diversity of zooplankton community differentiated among the six sampling sites.The richness and biomass ranked the highest in the estuaries of Baihe and Chaohe,next in the shallow habitats of Yanluo and Jingou,and the lowest in the deep habitats near the Baihe Dam and Chaohe Dam.But no significant differentiation was detected between the sites in each month.The stability and succession tendency of the zooplankton community structure reflects that the water quality is good in the reservoir in our sampling year and the aquatic ecosystem keeps free from the stress of eutrophication or other environmental processes.