Differences in vegetation and soil characteristics at different water-level altitudes in the drawdown areas of Three Gorges Reservoir area

Abstract

Vegetation and soil are the key components of the drawdown area of Three Gorges Reservoir.To investigate characteristics of vegetation and soil from water-level altitude of 160 m and 170 m,three drawdown areas with similar geological environment and history of land-use in Zhongxian County were chosen.Results indicated that percent of annual and perennial herbaceous species in drawdown area were 72.4% and 27.6%,respectively.There were no significant differences in species composition,coverage,biomass and biodiversity index between 160 m and 170 m.With water-level altitude changing,the dominant species of plant community varied.Cynodon dactylon was the dominant species at 160 m,while Conyza japonica at 170 m.Soil bulk density,water content,pH,SOM,TN and TP at 160 m and 170 m did not differ significantly.Therefore,it seems reasonable to suggest that their different dominant species resulted from the different inundation period and water depth in those areas between 160 m and 170 m,which did not play a significant role in current vegetation and soil development.