The Relationship Between Spatial-temporal Distribution Of Free Floating Plants And Water Quality Of Hemu Wetland

Aquatic plants play an important role in the wetland ecosystems. Not only can it absorb nutrients, heavy metal and organic pollutant, but also improve ecosystem function of wetlands. Free floating plant is an important part of aquatic ecosystem, it plays an important role on the maintain stability of the ecosystem for the conservation of biological diversity. This research investigated the characteristic of spatial and temporal distribution of floating plant distribution, biomass and elemental content and the relationship with water quality. Aims of the study is achieving the diagnosis and monitor of water environment in ponds by monitoring floating plants, and providing a scientific basis in use of floating plants to purify water and the matters need to attention. Through investigating the quality of live plants and wetlands four times(May, August, November in 2014 and February in 2015) in one year, this paper get following conclusions:1. There were four kinds of floating plant including Eichhornia crassipes, Lemna spp., Salvinia natans, Azolla imbricate.2. The floating plants distribution shown significant differences in four seasons. The proportion of floating plants distribution in the pond was larger in May and November. In May the total biomass of floating plants was the lowest and November was the highest. The CV of floating plants biomass in May and November have obvious differences. Duckweed had a great competitive advantage in four floating plants.3. The differences about the spatial and temporal distribution of floating plants coverage were significant. The average coverage of floating plants was lowest in May, and as well as the CV of space. In February, the value of floating plants coverage was the lowest in four surveys and CV of space was minimum, the cover of duckweed was significant different.4. The contents of element varied in each plant species. The N/P of duckweed was significantly different in temporal special, the differences among P content of temporal with Lemna, Salvinia, Azolla and Eichharnia were significant.5. The differences among the spatial and temporal distribution of water quality andthe spatial distribution were obvious. The water quality degree of Hemu wetland was IV in May, and III in August and November, which trends to be better totally. Multiple environmental factors had impacts on the Chla content, which a highly significant relationship with p H in each months.6. Whether the presence of floating plants was influenced by the combined effects of several water environmental factors. The differences about the spatial and temporal distribution of water quality and the spatial distribution were obvious. There was a significant relationship between distribution of floating plants and whether adjacent to the river in November and February.7. The relationship between the spatial and temporal distribution of floating biomass plants and water quality factors were different. Floating plant had a significantly positive correlation with water TN, NH4+-N, COD, NTU, but had significant negative correlation with water NO3--N and p H.8. The relationships between floating plants element contents and specific leaf area with water factors were different among species. The element contents had a correlation with environmental factors. The specific leaf area had a correlation with environmental factors, but not significant.