A COMPARATIVE STUDY ON AQUATIC PLANT DIVERSITY IN FIVE LARGEST LAKES OF HUBEI PROVINCE IN CHINA

In order to provide references for the monitoring and conservation of aquatic plant diversity in Lake Futou, Honghu,Liangzi,Changhu and Xiliang of Hubei Province in China,the species and community diversity and their long-term changes in the last fifty years were studied using field investigation(from 1999 to 2001),geographical information system technique (GIS) and global position system technique (GPS).The relationship between diversity loss and human disturbance intensity was also analyzed in the paper.Besides,the authors discussed the mechanisms leading to the diversity loss.The main results are summarized as follows:(1)It was found that in the year 2001,there were 61,94,87,92 and 77 aquatic plant species in Lake Futou,Honghu, Liangzi,Changhu and Xiliang ,respectively. Among the five lakes,Lake Futou and Honghu(experiencing the highest disturbance intensity)showed the lowest species to area ratio(0.53 species/km2and 0.27 species/km2,respectively). The highest value, 1.07species/km2,was found in Lake Xiliang(with the lowest disturbance intensity).(2)At present,there were 5,5,12,12 and 13 aquatic plant associations in Lake Futou,Honghu,Liangzi,Changhu and Xiliang,respectively.The vegetation in the five lakes,with respective coverage of 16.30%,16.43%,32.56%,45.16% and 62.04%,showed the mean biomass in the whole lake of 299.0g/m2,764.2g/m2,808.6g/m2,1039.1g/m2and 1719.8g/m2(fresh weight),respectively.(3)It was found that in the last fifty years,9,8,5,3 and 1 aquatic plant species,and 7,8,4,2 and 1 associations had disappeared from these lakes,respectively.(4)The results indicated that aquaculture in enclosures(from the late 1980s to the present )decreased aquatic plant diversity in the five lakes much more than inning of the lakes(from the early 1950s to the early 1980s).And the richness of aquatic plant diversity in the five lakes was negatively related with human disturbance intensity experienced by the lakes.Whereas the relationship between diversity loss and the disturbance intensity was just the opposite.