The Restoration of Aquatic Vegetation in Lakes of Poyang Lake Nature Reserve after Catastrophic Flooding in 1998

The internationally important wetland,Poyang Lake Nature Reserve has several small lakes relatively independent from Poyang Lake.The aquatic plants in these lakes were destroyed by a catastrophic flooding occurred in 1998.The restoration of the aquatic vegetation following the high water stress was analysed by comparing the results of vegetation investigation in 1999 and 2001,as well as the historical data.The species number and the biomass in 1999 were lower than those before the flooding.However,species had restored by 2001,and the biomass of Vallisneria spp.and Hydrialla verticillata had exceeded that before the stress,but the biomass of the rest plants were still low.It was suggested the different restoration of plants were mainly related with their different vegetation propagation methods.The vegetation restoration in lakes of Poyang Lake Nature Reserve was different from that in temperate and other subtropical lakes in that no pioneer stage when Chara dominated occurred.The reason was that the frequent severe fluctuation of water levels in Poyang Lake affected the settlement of Chara.In the paper,we think that the decline of biomass of aquatic plants and the species number was just a short-term effect;and it will spend several years to restore the lake vegetation.