A COMPARATIVE STUDY ON AQUATIC PLANT DIVERSITY AND ITS LONG-TERM CHANGES IN THE THREE LAKES OF DONGTINGHU DISTRICT IN CHINA

The aquatic plant diversity and its long term changes in the three lakes of Dongtinghu District in China were comparatively studied in this paper The adaptive mechanisms of Trapa incisa, Vallisneria denseserrulata and Potamogeton crispus to human disturbance were also investigated Besides, the approaches to restore the aquatic plant diversity and the degraded aquatic ecosystems of Lake Datonghu and Nanhu were suggested The main results are:(1)During 1999-2000,61,56 and 32 aquatic plant species were recorded in Lake Donghu,Datonghu and Nanhu,respectively.And 8 and 6 aquatic plant associations were identified in Lake Donghu and Datonghu, respectively, whereas only 4 associations were found in Lake Nanhu The respective aquatic vegetation coverage of the three lakes were 26 17%,10 60% and 9 99%(2)Comparaed with the studies in the early 1970s,3,9 and 13 aquatic plant species,2,5 and 5 aquatic plant associations were found to have disappeared from Lake Donghu, Datonghu and Nanhu, respectively(3)The results indicated that the aquatic plant diversity in the three lakes is in the order of Lake DonghuDatonghuNanhu at present, and the decrease of aquatic plant diversity in the three lakes were positively related to the intensity of human disturbance