Interannual variations of vegetation and soil nutrients in the water level fluctuation zone in the Three Gorges Reservoir
The Three Gorges Dam significantly prolonged the submergence duration (at least two months) and resulted in the reversal of natural flood rhythms (winter submerged and summer exposed). To investigate the effects of annual hydrological regime on vegetation and soil nutrients, we conducted a field survey in purplish soil in the water level fluctuation zone (WLFZ) from 2009 to 2011. The vegetation composition, flooding characteristics and soil nutrients were determined in three zones of 145-155 m, 156-165 m and 166-175 m. Univariate two-factor analysis and redundancy analysis were used to identify the key environmental factors influencing vegetation. The results showed that vegetation in the WLFZ was dominated by perennial herbs such as Cynodon dactylon and Cyperus rotundus and annual herbs such as Xanthium sibiricum and Comnyza Canadensis. The dominances of C. dactylon and C. rotundus increased from 2009 to 2011, however, the dominance of Xanthium sibiricum declined. The averages of Shannon-wiener index, Margalef index, Pielou evenness index and Simpson index were 2.43±0.55, 4.72±2.28, 0.80±0.06 and 0.86±0.08. The differences in the height, Shannon-wiener index and Simpson index of the vegetation exhibited statistical significance with respect to elevation and to year. The averages of the concentrations of soil organic matter, total nitrogen and total phosphorus were 14.23±4.70、0.65±0.37 and 0.47±0.24 g/kg, respectively. The differences in both total nitrogen and total phosphorus presented statistical significance with respect to year but not with respect to elevation. The key environmental factor that influenced the importance value index of species was the submerged time.
vegetation diversity Three Gorges Reservoir water level fluctuation zone
Zhiyong Zhang Chengyan Wan Zhiwei Zheng Jianbo Chang Lian Hu Hongqing Hu
A Key Laboratory of Ecological Impacts of Hydraulic-Projects and Restoration of Aquatic Ecosystem of A Key Laboratory of Ecological Impacts of Hydraulic-Projects and Restoration of Aquatic Ecosystem of College of Resource and Environment, Huazhong Agricultural University, Wuhan 430070, P. R. China
国际会议
The 3rd Biennial ISRS Symposium Achieving Healthy and Viable Rivers (ISRS)第3届国际河流大会
北京
英文
657-666
2013-08-05（万方平台首次上网日期，不代表论文的发表时间）