Plant Community Structure And Ecological Adaptation Of Dominant Species In Wetland Of Caizi Lake In Anhui Province

Wetland was known as the "natural kidney ", is the transition areas between the land and the water in the earth, which is the ecosystem with special activity and function. In wetland ecosystem, wetland plants are the main primary producers to stabilize structure and function of the ecosystem. Caizi Lake which is connect-river is typical of shallow freshwater wetlands, located in the lower and middle reaches of the Changjiang River. The area of Wetland vegetation of Caizi Lake decreased rapidly due to human disturbance. In order to protect and develop wetlands, we need to focus on this phenomenon.Wetland plant species composition, dominant associations and dominant species biomass of Caizi Lake has been investigated in this thesis, and ecological adaptation of dominant species have also been studied. The main results as follows:(1) Wetland plant species composition of Caizi Lake were investigated in July 2008-July 2009. There are 147 vascular plant species belonging to 101 genera in 42 families. Pteridophyta 4 species belonging to 4 genera in 4 families which accounted for 3%; Dicotyledoneae 88 species belonging to 58 genera in 27 families which accounted for 60%; Monoctyledonea 55 species belonging to 39 genera in 11 families which occupied 37%. According to the classification system of life-form,147 different species can be divided into hygrophyte plants, submersed plants, floating plants and emergent plants.104 species of hygrophyte plants belonging to 76 genera of 25 families which accounted for 71%,20 species of Gramineae,14 species of Cyperaceae,13 species of Polygonaceae and 13 species of Compositae constitute hygrophyte plant communities.18 species of floating plants belonging to 12 genera of 11 families which accounted for 12%, species of Trapaceae constitute floating plant communities.14 species of submerged plants belonging to 9 genera of 7 families which accounted for 10%, plant of Hydrocharitaceae, Potamogetonaceae, Haloragidaceae and Ceratophvllaceae constitute submersed plant communities.11 species of emergent plants belonging to 7 genera of 6 families which accounted for 7%, Zizania latifolia and Phragmites australis are the main species to compose emergent plant communities.The average biomass of fresh aquatic plant in the whole lake is 369.9 g/m2,and the dry weight is 71.0 g/m2.(2) Compared with that in 2008, the total quantity and the distribution of the hygrophyte plant communities in 2010 changed little. Aquatic plant has greatly changed, the coverage of vegetation in the whole lake has reduced 87.5%, and the dominant associations have decreased 53.8%, the coverage of dominant associations has lessened 82.5%.(3) Three dominant species on the lake beach, Ranunculus polii, Carex thunbergii and Potentilla supine, have different niches. Ranunculus polii near the water side, living lower altitude. Potentilla supine near the top of shore, living higher altitude. Carex thunbergii is distributed between Potentilla supine and Ranunculus polii. Three dominant species exhibited typical zonal distribution. The sexual reproduction of three dominant species can be completed before the flood coming, while the three dominant species stored more nutrients in the roots to regrow after the waters receded.