Distribution of Duckweed Community and the Environmental Factors that Affect the Community Structure

Key words: 
• duckweed /
• distribution /
• population structure

Abstract: The duckweeds growing in Hainan Island were collected thrice from May to August 2013,and 34 communities of the duckweeds were sampled from 13 cities/counties of Hainan Province,from which 45 ecotypes of duckweeds were identified under 4 species of duckweeds,Wolffia globosa,Lemna aequinoctialis,Spirodela polyrrhiza and Landoltia punctata. The distribution of three species of the duckweeds except L. punctata was analyzed and the factors of water affecting the community structure,such as p H,N and P content of water on which the duckweeds grew were determined. L. aequinoctialis were found to distribute most widely throughout the whole island; W. globosa were distributed mainly in the north of the Island; S. polyrrhiza and W. globosa were also distributed in different large areas but much less widely than L. aequinoctialis. The duckweeds grew mostly in the quiet and seriously polluted water from sewage treatment plants,waste ponds,etc. The water nutrients and their content were detected to analyze their relationship with the growth of each species of duckweeds by using one-way ANOVA and one-way MANOVA. Results revealed no obvious relationship between the distribution of duckweeds and their growth water environment,but only an occasional phenomenon. Moreover,the duckweeds were observed under a simulated natural growth environment to see the impact of temperature and water nutrients on the growth of the duckweeds and the duckweed community structure,and the results showed that the temperature had a greater impact on the duckweed community structure than the water nutrients.