中文摘要：

为了解三峡水库蓄水后消落带植物群落的特征,于2008年7—9月对重庆市开县消落带进行现场调查,并应用双向指示种分析法（TWINSPAN）和除趋势对应分析法（DCA）对三峡水库156 m蓄水后消落带植物群落进行数量分类和排序。结果表明,TWINSPAN将170个样方划分为19类,其中具代表性的主要植物群落为水蓼（Po-lygonum hydropiper）群落、苍耳＋狗牙根（Xanthium mongolicum＋Cynodon dactylon）群落、苍耳（X.mongolicum）群落、双穗雀稗（Paspalum paspaeoides）群落和白茅（Imperata cylindrical）群落,反映了因海拔变化（145~156 m）而导致的淹水时间的差异。DCA排序结果显示,淹水时间、土壤湿度和土壤质地是消落带植物群落组成和空间分布的主要限制性影响因子。

英文摘要：

The water level of the Three-Gorge Reservoir（TGR） rose up to 156 m in the end of October 2006,which indicated that the Three-Gorge Project had begun its operation.In order to understand how the operation affects structure and composition of the plant community in the hydro-fluctuation area,an investigation of the plant communities in Kaixian County was carried out from July to September in 2008.The findings of the field survey were analyzed quantitatively with the TWINSPAN（two way indicator species analysis） and DCA（detrended correspondence analysis） methods for ordination.Results show that the TWINSPAN method sorted 170 quadrats in the study area into 19 types,among which Polygonum hydropiper,Xanthium mongolicum＋Cynodon dactylon,X.sibiricum,Paspalum paspaeoides,and Imperata cylindrical were the most representative plant communities,revealing a distinct relationship between the plant communities and environmental gradients.Results of the DCA ordination by DCA indicated that submergence time,soil humidity and soil texture are the major factors affecting distribution and composition of plant communities in the area.