Quantitative Analysis of Plant Communities in Water- level-fluctuation Zone within Three Gorges Reservoir Area of Changjiang River

Based on field survey for plant community by quadrates, both quantitative and ordination analyses of plant communities in water-level-fluctuation zone within Three Gorges Reservoir Area of Changjiang River were performed using TWINSPAN (Two Way Indicator Species Analysis) and DCA (Detrended Correspondence Analysis) methods. One hundred and twenty-two quadrates collected from the study area were classified into nineteen types by TWINSPAN, and four vegetation types were identified. The result revealed a relationship between the plant communities and environmental gradients, which is also confirmed in the chart of DCA. Diagonal line of the two-dimensional ordination diagram of DCA indicated that soil water content is highly correlated to submersed duration in the areas, suggesting that the major factors restricting distribution and composition of plant communities are submersed duration and edaphic humidity. Analysis of the composition and distribution of those communities provides a baseline data for selecting plants for reconstructing water-level-fluctuation of Three Gorges Reservoir in the future.