Abstract: To study the response of terrestrial plants in hydro-fluctuation belt to the first time habitat flooding-drying cycle in the Three Gorges Reservoir Area, Yangtze River, we investigated community characteristics, such as plants composition, number of individuals, species coverage, when this place was flooded in winter and then exposed in summer in the elevation from 156 to 172 meters. We calculated species’ important value as well as the proportion of all plant life forms in the community. The result showed that there were 147 vascular plants species belonging to 55 families before the fluctuation cycle. However, there were only 32 species belonging to 17 families after the fluctuation cycle and the proportion of families and species were reduced by 69.1% and 78.2%, respectively. Meanwhile, the plots newly emerged 49 plant species which accounted for 60.5% in the total species. The composition of plant life forms changed, that is, trees and shrub species declined while the herbaceous increased. Different plants reacted differently to environmental changes. Cyperaceae, Gramineae, and Compositae herbs showed a strong adaptation capacity to the change. The representative species were Cyperus rotundus, Setaria viridis, Bidens tripartite, Digitaria sanguinalis, Gynura crepidioides, Artemisia apiacea, etc. One-year-old seedlings of shrub species of Vitex negundo, Rhus chinensis, Discocleidion rufescens, Coriaria nepalensis , Myrsine africana, and tree species of Sapium sebiferum, Koelreuteria bipinnata, Broussonetia papyrifera all showed strong adaptability.

Key words: hydro-fluctuation belt, terrestrial vegetation, ecological adaptability, Three Gorges Reservoir