Succession of macrophyte communities and its driving factors in Wuli Lake of Taihu Lake

Based on investigation data from 2003-2005 and past studies,the dynamic changes of macrophyte communities in Wuli Lake and their driving factors are analyzed.The following conclusions can be drawn:(1) The succession of macrophyte communities can be divided into three stages: a long evolvement stage before 1970s,a rapid degradation stage from the 1970s to 2002,and a restoration stage after 2002.Before the 1950s,there were abundant macrophytes with high coverage and various life forms in the lake.During the second stage,macrophytes disappeared rapidly and,thereafter,creeks and ponds around the lake became refuges of remnant macrophyte.Now there appear abundant macrophytes in the demonstration-project areas and sparse macrophytes near the banks outside of the demonstration-project areas.(2) Macrophyte communities change with the variations in water quality,sediment,fish and reclamation activities.The disappearance of macrophytes results from many factors which are associated with human activities and coupled with each other,forming a lot of positive feedbacks.