The Research On Plant Community Design Of City Park Green Space Based On Ecological Priority

With the acceleration of urbanization,the problem of urban ecological environment is becoming more and more serious.Urban park green space has become the key to urban ecological construction because of its significant proportion in the city and its close relationship with human activities.As the most important component of urban park green space,plant community,through its own role,changes the internal and external habitat factors,and affects the ecological environment of urban park green space and even the global region.At present,most of the relevant studies at home and abroad start from the perspective of aesthetics and take design priority as the principle to construct the plant community of urban park green space.Therefore,although urban park green space has certain ecological benefits,it has not been given full play and the cost is high.This study in Hefei city park green space plant community as the research object,with the orientation of ecological priority,in different habitat types of landscape plant community characteristics and ecological benefits as the research basis,and combined with the comprehensive evaluation results of the growth condition of plant community,and,in turn,analysis of different habitat types and ecological benefits of plant community landscape characteristics and growth condition,optimize the part of the plant community design,so as to put forward the problems existing in the Hefei city park green space plant community as well as the corresponding optimization Suggestions,finally put forward based on the ecological priority of the construction of the city park green space plant community optimization model,The optimal model was deduced for the plant communities of 4 habitat types.The main results are as follows:(1)Community survey and landscape analysis were conducted on 28 plant community sample plots of different habitat types from three aspects:species diversity,ecological structure,green quantity and landscape characteristics.The species composition,frequency,relative abundance and importance value of the plant community were calculated,and the results showed that different habitat types of the park green space in Hefei used more arbor,shrub and grass layer plants.Of plant community species diversity index,species evenness index and species richness index calculation,the average highest species diversity index of shrub layer,is 0.624,the average tree layer species diversity index is 0.559,the average herb layer species diversity index is 0.455,sun dry plants habitat of the layers of plant community species diversity index of the highest;Tree species of the vertical structure of shrubbery layer density and the application of evergreen tree species and deciduous tree species in each layer were analyzed,and found in Hefei understory shrubs in the park green space utilization degree is higher,however,the tree layer application application layer of evergreen trees and shrubs are more,the tree layer of evergreen tree species relative density 0.513,deciduous trees,relative density 0.487,evergreen tree species in the shrub layer relative density 0.910,deciduous species relative density is 0.090;It was found that the average green amount per unit area of the park green space in Hefei was 7.94×104m2/hm2,65%of the plant communities concentrated between 6.0-9.0×104m2/hm2,and the highest green amount per unit area of the positive wet habitats was 9.04×104m2/hm2.(2)according to the ecological benefits of green plant calculation method,calculation and statistics to carbon release oxygen humidification and cooling as an index of the ecological value and ecological value per unit area,can be found in Hefei carbon quantity per unit area of park green space plant community was 76.82 g,m-2,d-1,release oxygen content is 52.20 g per unit area,the m-2,d-1,temperature and the amount per unit area is 1.73℃ the m-2,d-1,increases the moisture content is 11916.95 g per unit area,the m-2,d-1.Among them,the ecological benefit values of the sun wet habitat were higher,while those of the shade dry habitat were lower.(3)Through field observation,12 specific indexes including naturalness,health,ornamental value and the following indexes can be used to better characterize the growth status of plant community.Through continuous observation of 28 plant communities,it is found that the community model of layered structure is generally superior to that of single-layer structure.By establishing the evaluation system of plant community growth status,the plant community growth status in different habitat types was analyzed.Among them,the sun wet habitat plant community 2-6 highest comprehensive evaluation,comprehensive evaluation score of 14.04,a comprehensive evaluation level for Ⅰ;Yin wet raw habitat plant community minimum 4-6 comprehensive evaluation,comprehensive evaluation score of 7.05,a comprehensive evaluation of grade Ⅲ.The comprehensive ranking of the 4 habitat types was:the sun wet habitat>the sun dry habitat>,the shade dry habitat>the shade wet habitat.(4)the combination of ecological benefits of quantitative analysis and comprehensive evaluation of plant community growth status and qualitative quantitative judgment,selection of ecological benefits of low and high comprehensive evaluation,ecological and comprehensive evaluation of low,ecological benefit and comprehensive evaluation of five plant community put forward the corresponding optimization strategy,and analyzes the problems existing in the Hefei city park green space overall plant community,and then proposes the corresponding optimized design proposal.Based on the above research,an ecological priority based optimization model of plant community in urban parks was proposed.This study not only provides scientific basis and solutions for the ecological benefit research and optimal allocation model of urban park green space,but also plays a positive role in the ecological construction of other urban green space.This study hopes to realize the ecological construction of specific sites in urban green space from the micro level,and finally make a contribution to the optimization of urban living environment.