青弋江芜湖段轮虫群落结构和物种多样性的初步研究

Community structure and species diversity of rotifers in the Wuhu section of the Qingyi River

20 0 3年 1- 12月 ,对青弋江芜湖段轮虫群落结构和物种多样性的周年动态进行了初步研究 ,并分析了轮虫密度与水温、水体叶绿素a浓度和水流量等环境因子的关系 ,以便为我国轮虫区系以及河流中轮虫密度的季节变化规律的进一步研究提供基础资料。经鉴定 ,共发现轮虫 10 4种 ,其中钳枝巨头轮虫 (Cephalodellaforceps)、长趾巨头轮虫 (C .macrodactyla)、尾钩巨头轮虫 (C .mucronata)、奇槌巨头轮虫 (C .evabroedi)、突纹腔轮虫 (Lecanehornemanni)、爱沙腔轮虫 (L .elsa)、长趾似月腔轮虫 (L .lunarisacus)和泛热三肢轮虫 (Filiniacamasecla)等 8种轮虫为我国亚热带地区的新记录种 ;优势种为螺形龟甲轮虫 (Keratellacochlearis)、广生多肢轮虫 (Polyarthravul garis)和无尾无柄轮虫 (Ascomorphaecaudis)。 1- 4月 (汛期前 ) ,轮虫总密度与水温、叶绿素a浓度之间均呈现出显著的正相关关系 (r =0 .5 33,P <0 .0 5 ;r=0 .5 4 8,P <0 .0 5 ) ;而在 5 - 9月 (汛期 ) ,轮虫总密度与水流量之间表现出显著的正相关关系 (r =0 .5 80 ,P <0 .0 1) ;10 - 12月 (汛期后 ) ,轮虫总密度和水温、叶绿素a浓度和水流量之间都表现出显著的正相关性 (多元回归 ,R2 =0 .6 80 ,P <0 .0 5 ) ;水流量对 10 -

The annual dynamics of community structure and species diversity of rotifers in the Wuhu section of the Qingyi River was studied in the year 2003, and the relationships between rotifer density and ecological factors including water temperature, Chl-a concentration and river discharge were analyzed for further understanding of China rotifer fauna and the pattern of seasonal variation of rotifer density in rivers. One hundred and four rotifer species were identified, of which Cephalodella forceps, C. macrodactyla, C. mucronata, C. evabroedi, Lecane hornemanni, L. elsa, L. lunaris acus and Filinia camasecla were confirmed as new records in the subtropical region of China. The dominant species were Keratella cochlearis, Polyarthra vulgaris and Ascomorpha ecaudis. The total density of rotifers was positively related to water temperature and Chl-a concentration (r=0.533, P<0.05; r=0.548, P<0.05) during January-April (before flood season), but it was positively correlated with river discharge (r=0.580, P<0.01) during May-September (during flood season), and with water temperature, Chl-a concentration and river discharge (multiple-linear regression, R 2=0.680, P<0.05) during October-December (after flood season). River discharge had the greatest effect on the total density of rotifers during October-December (standardized partial regression coefficient: β 1=0.312, β 2=0.120, β 3=0.593). Across the year, species diversity index was positively associated with number of species and species evenness of the community (n=12, r 1=0.600, P<0.05; n=12, r 2=0.955, P< 0.001 ), but negatively associated with dominance (n=12, r=-0.942, P<0.001).