| In this paper, the typical sampling survey was used, the results were found by researching and studying 37 plant communities of urban green space in Lin'an City: Among the applicated plants of the artificial plant commnunities in the urban green space, there were 123 species, 90 genus and 53 families of plants, of which were Gymnosperm 13 species, 11 genus and 7 families, Angiosperms 110 species, 79 genus and 46 families. The 37 plant communities of green space in Lin'an City can be divided into the following 4 samples of plant community: Evergreen and deciduous conifer mixed type holding 12 samples of plant community, deciduous broad-leaved type holding 1 sample of plant community, evergreen broad-leaved type holding 8 samples of plant community, Evergreen and deciduous mixed type holding 16 samples of plant community. The most abundant species was arbor layer, the richness index of arbor layer was 1.6 times the shrub layer and 5.2 times the herb layer. The average species richness of the tree, shrub and herb in the 37 plots was 4.1, Margalef average index was 0.927, Simpson average index was 0.613, Shannon-Wienner average index was 1.372 and Pielou evenness average index was 0.790. The results: A significant positive correlation between species richness and the Margalef index (P﹤0.01), a significant positive correlation between species richness and Shannon-Wienner index (P﹤0.05), and a significant positive correlation between Simpson index and Shannon-Wienner index (P﹤0.01), a significant positive correlation between Simpson index and Pielou evenness index (P﹤0.05).The average leaf area index of green space in Lin'an City was 2.21. the average gap fraction was 30.7%. There was a significant negative correlation between the leaf area index and the average gap fraction (P﹤0.05), a significant positive correlation between leaf area index and species richness, Margalef index, Simpson index, Shannon-Wienner index (P﹤0.05).The results of the ecological benefit researches in Lin'an City: the ecological benefit of urban green space was not well as suburban green space and a large gap was existed. The difference of the daily average temperature of urban green space and suburban green space between summer and winter was 1-2℃. The effect of reducing the temperature and increasing humidity of public facilities green space was best. The dust concentration, carbon dioxide concentration and noise figure in urban green space were higher than the suburbs. When air quality was evaluated by aero-anion concentration, in winter the air of urban green space was maintained in a clean standard and the overall condition was well, but air quality of road green space was general, roadside green space maintained in the allowed range. The air quality of urban green space was in the second standard in summer and winter when it was evaluated by respirable particulate matter levels, the air quality was well. The Evergreen and deciduous mixed type was thought to be best in the capacity of reducing the temperature and increasing humidity, fixing carbon and releasing oxygen, reducing dust and noise, and the ecological benefit is better when the plant communities was composed by the mixed evergreen and deciduous trees, or mixed broadleaf and conifer trees than the pure evergreen tree or deciduous trees. The ecological benefits of the plant communities containing the trees, shrubs and grass is better than the plant communities only containing shrubs and grass. The ecological benefit of lawn was worse. A significant positive correlation (P﹤0.01) between the aero-anion concentration and the relative humidity, a significant negative correlation (P﹤0.01) between the aero-anion concentration and air temperature, a significant positive correlation (P﹤0.05) between the aero-anion concentration and dust; In six green space, a significant difference (P﹤0.01) between aero-anion concentration and noise, a significant difference (P﹤0.05) among carbondioxide, dust, light intensity and relative humidity, but no significant difference in air temperature. |
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