中文摘要：

通过对洞庭湖六门闸至小西湖样带的调查,研究了封闭河口区和湖心区水体、土壤和植物等基本生态特征及其相关关系。结果表明,河口区水流缓慢,透明度低,而湖心区水流速度较高,透明度也高;河口区水体具有较高的营养水平和电导率,而湖心区水体营养水平和电导率相对较低;湖心区土壤有机质和氮含量较高,而河口区有机质和氮含量相对较低;河口区不适合水生植物的生长繁殖,而湖心区是植物生长繁殖的主要生境。相关分析结果表明,河口区和湖心区生物、土壤和水文特征之间存在相互作用,透明度与水流速度之间在α=0.05水平上相关显著,物种丰富度、生物量和多样性指数分别与水流速度和透明度在α=0.01水平上相关显著,与土壤全氮含量之间在α=0.05水平上相关显著,水流速度是调控生态特征变化的关键因子。

英文摘要：

Basic ecological characteristics including water body,soil and plants as well as their correlations in an enclosed estuary and centre of Dongting Lake were systematically studied by field investigation of the sampling belt from Liumen Gate to Xiaoxi Lake.Results indicate that in the enclosed estuary the flow was slow and the water was low in transparency,whereas in the centre of the lake,just the contrary;the water in the enclosed estuary was higher in nutritional level and conductivity than the water in the centre;the soil in the centre was higher in organic matter and nitrogen content than the soil in the enclosed estuary;and the enclosed estuary was not fit for aquatic plants to survive in while the centre was the main habitat of aquatic plants.Further correlation analysis shows that mutual effects and interactions existed between the two zones in biological,soil and hydraulic characteristics.Transparency was significantly correlated with water flow velocity（α=0.05）.Species richness,biomass,and biodiversity were significantly correlated with water flow velocity and transparency,respectively（α=0.01）,and with soil total N（α=0.05）.Water flow velocity was the key factor in regulating ecological characteristics.