Ecological Study On Ciliates In The Cage Fish Culture Farm Of Liujiaxia Reservoir

The community structure of ciliates in the cage fish culture farm of Liujiaxia reservoir was studied by field investigations from March 2006 to February 2007. The main results are as follows:1. Eighty one species of ciliates including five unnamed species were recorded in this paper. They were belonging to three classes, eleven orders, thirty five families and forty four genera.2. The results of study on distribution of species of ciliates showed that both spatial distribution and temporal distribution had obvious heterogeneity.3. The results of study on community structure of ciliates showed that Hypotrichida was dominant group, Prostomatida was subdominant group. Hymenostomatida, Scuticociliatida and Pleurostomatida were common groups. Heterotrichida was incidental group. The dominant species of ciliates were Cyclidium versatile,Cyclidium granulosum,Cinetochilum margaritaceum,Chilodonella uncinata,Litonotus obtusus,Strobilidium gyrans,Halteria grandinella,Leptopharynx eurystoma and Glaucoma macrostoma, in which Cyclidium granulosum was first dominant species, Cyclidium versatile and Cinetochilum margaritaceum were second dominant species.4. Annual dynamics and seasonal dynamics of community of ciliates were investigated. The results indicated that the annual dynamics of species numbers took on distinct one-peak pattern, and the most numbers of species was fifty two in August and September, the least numbers of species was eighteen in March. The seasonal dynamics of species numbers showed that the most numbers of species was sixty five in summer, the least numbers of species was forty eight in winter. The annual dynamics of abundance took on distinct three-peaks pattern, the first summit appeared in April, the second summit in July and the third summit in September. The water transfer of Liujiaxia Reservoir in May brought on a sharp decrease of abundance in this month was the reason of three-peaks pattern of abundance. The seasonal dynamics of abundance showed that the highest abundance was in summer, the lowest was in winter. The annual dynamics of the species diversity index demonstrated that the highest value appeared in August, and the lowest in March. 5. Feeding habits of ciliates in the cage fish culture farm of Liujiaxia Reservoir were analyzed. The result showed that the total percentage of both P group and A group in the I～V sampling sites was 35.1%, B group accounted for 48.1%. While in the contrast sampling site, those were 38.6% and 43.2% respectively. In view of the comparison of functional-trophic groups among ciliates, the water quality in the I～V sampling sites was better than contrast sampling site.6. The correlation analysis between environmental factors and structural parameters of ciliates community showed that among temperature, pH value, transparent degree and food, the influence of temperature on species numbers in the cage fish culture farm of Liujiaxia reservoir was the greatest, then that of transparent degree, and then that of pH value, the least that of food. The influence of food on abundance was the greatest, then that of temperature, and then that of pH value, the least that of transparent degree.