A Preliminary Study on the Vascular Plant Flora of the Water-Level-Fluctuating Zone in the Three-Gorge Reservoir Area

The water-level-fluctuating zone in the Three-Gorge Reservoir Area is a belt zone of the bank beside Yangtze River and its branches in the Three-Gorge Reservoir Area,which emerges and submerges periodically with the water level fluctuating seasonally.The vascular plant flora in this area shows many characteristics:the vascular plants are relatively abundant in species,and there are 377 species,26 varieties and 2 forms,which belong to 240 genera,83 families.It is complex in geographical elements,having an extensive connection with nearby floristic area,and has more temperate plants than tropical ones;the floristic composition shows an evolutionary trend,and the life form constitutes with many perennial herbs,annual herbs and shrubs;there are few endemic plants to this area,but many endemic species to China;species richness of the plants in different parts of this area are not even.Namely,those in main channel,east to Fengjie,and the upside are higher than in branches,west to Fengjie,and middle part and downside respectively;the vascular plant flora in this area is characterized by not only obvious dominance phenomena but also abundant characteric taxa.