Abstract: The impact of reservoir construction on plant diversity and distribution pattern of wetland is a hot topic recently. Due to different development time, cascade reservoirs have become an ideal research platform for utilizing space instead of time. We can evaluate the impact of reservoir on diversity and pattern of wetland plants at the temporal scale through comparing the differences of wetland plants population structure among the cascade reservoirs. In this study, we exploited 8 representative reservoirs and established 3 different transects among the riparian ecotone of each reservoir of the Wujiang River. Our aim is to evaluate the impact of the reservoir on wetland plants population diversity and pattern. Our results indicated that there were 247 species belonging to 84 families and 199 genus among these 8 cascade reservoirs of Wujiang River. The Gramineae was the biggest family which contained 24 species while Polygonum is the biggest genus which contained 6 species. The dominant species are Imperata cylindrica, Rhus chinensis, Rosa laevigata, Conyza canadensis and Cynodon dactylon. The results of wetland plants pattern indicated that the population structure of Wujiang cascade reservoir showed a clear zonal distribution pattern. The first sampling transects (water fluctuation zone) was quite different from the second and the third transects (non water fluctuation zone). The diversity of the plants in riparian zone have the close relationship between reservoir elevation, reservoir construction time and reservoir slope. Our results indicate that the future study on wetland plants should focus on the water fluctuation zone.

Keywords: cascade reservoirs; riparian ecotone; wetland plants; distribution pattern

EARTH AND ENVIRONMENT Vol.47, No.6, Tot No.332, 2019, Page 760-767