洞庭湖鱼类的群落结构及其时空动态

SPATIO-TEMPORAL VARIATIONS OF FISH ASSEMBLAGES IN THE DONGTING LAKE

为系统研究洞庭湖鱼类群落结构及其时空动态,于2012年12月至2014年10月对洞庭湖进行了2周年的季度鱼类调查,共采集鱼类80种,隶属于7目17科54属,其中鲤科种类最多,占总数的58.8%。与历史记录相比,洞庭湖鱼类减少了36种,其中山溪河流性鱼类和河海洄游性鱼类物种数和百分比均有下降,分别减少了13种(2.2%)和4种(3.0%)。分析显示洞庭湖鱼类的多样性和群落组成有显著的季节和区域差异,夏季和秋季的多样性和均匀性显著高于其他季节,东洞庭湖鱼类的多样性显著低于其他湖区。由于夏秋季为长江洪泛高峰且东洞庭湖距离江河较远,推测江河干流鱼类在洪泛和水文连通的支持下对通江湖泊的鱼类资源有重要的补充作用。研究提供了洞庭湖鱼类群落时空变动的本底资料,可为洞庭湖鱼类资源保护提供科学依据。

Lake Dongting is the second largest floodplain lake along the Yangtze River basin.However,the study on fish communities in the Dongting Lake is limited,lacking systematic research on the spatio-temporal variations of fish assemblages in this area.Fish were sampled seasonally from December 2012 to October 2014 in the Dongting Lake.80 fish species belonging to 54 genera,17 families,and 7 orders with dominant Cyprinidae accounting for 58.8%of the total species were collected.The species richness reduced by 36 in contrast with the historic records.The number and percentage of riverine and river-sea migratory species decreased by 13(2.2%)and 4(3.0%)respectively in comparison with historic records.We detected significant seasonal and regional differences in species composition and biodiversity.The diversity and evenness of fishes were significantly higher in summer and autumn than those in other seasons.Meanwhile,significantly lower diversity was observed in the east Dongting Lake than other regions.Our results indicated that seasonal flood pulses and,assisting by river-lake connectivity may play a fundamental role for the fish resources supplement in floodplain lakes.This study demonstrated significant spatio-temporal variations of fish assemblages in the Dongting Lake,which provided scientific foundations for fish conservation in this area.