Study On Diversity Of Woody Plant Communities In Nanjing City Green Space

As the urban population increases, a deteriorating urban environment makes people realize the importance of improving urban ecological environment.Biodiversity as an important part of urban ecological environment, it is closely related to human survival, the plant is the first producer in nature, is all living things (including humans) the material basis for the survival, the study of plant diversity in urban green space is urban ecological balance maintenance and urban biodiversity protection and construction of a basic way. Urban green space is made up of plant community as the basic unit, plant community supporting frame is one of the woody plants, ecological quality fit and unfit quality directly decides the woody plant community to improve the function of the urban environment quality, therefore, building a delicate landscape effect and ecological benefits of urban green space of woody plant community has great significance to the sustainable development of the city.Different types of urban green space have different configurations and features, decisions to create artificial plant communities with different species composition, structure and the characteristics of diversity. In this paper, through selecting 100 different types of urban green space of woody plant community related data collection and investigation, and analyzed the woody plant community species composition, computing in urban green space, and discusses the characteristics of various types of urban green space of woody plant community diversity, and built from function type, time, landscape forest type analysis of three different angles to find commonality and diversity characteristics differences between each type; Finally uses clustering analysis to the Nanjing urban green space of woody plant communities are classified, and try to find the same clustering groups outside the divided by dominant species for dividing basis, built in function type, time and location factors on common characteristics.The main results are summarized as follows:(1) By the survey results:Nanjing urban green space of woody plant communities were applied 169 kinds of garden woody plants, belonging to 60 families and 119 genera, species concentrated in some of the world’s great families and small species family (including two kinds and below), including 94 kinds of tree species,75 kinds of shrubs, shrub species is less; Application of 79 kinds of native plants (excluding domesticated species and naturalized species), accounting for 46.7% of the total sample to urban green space plant community composition.; In Woody plant communities of Nanjing urban green space, evergreen and deciduous broadleaf, evergreen broad-leaved landscape forest is given priority to, from the point of physiognomy feature, the proportion of coniferous and broad leaved tree species of woody plant community species approximately 1:7, evergreen and deciduous trees nearly 1:1 proportion.(2) From the functional type, building time, landscape forest types in three different angles of various types of green woody plant in Nanjing city communities richness index Shannon-Weinner index, Simpson index, evenness index comparison study found:Different functional types of woody plant communities in urban green space overall and each level of Shannon-Weinner index, Simpson index reflects a consistent, comprehensive park> Campus green space> Residential green space> Square green space> Road green space, large variations in tree layer, the overall level is higher and the evenness index change is not big, but there is large difference between the sorting. Urban green space of woody plant communities built in different time overall Shannon-Weinner index, Simpson index were new urban green space> early constructed urban green space, but the tree layer and shrub layer vary, evenness index differences due to the characteristics of each period configuration methods. Different types of landscape forest in urban space Shannon-Weinner index, Simpson index are evergreen and deciduous broadleaf landscape forest> evergreen broadleaf landscape forest> coniferous broad-leaved forest landscape> deciduous broad-leaved landscape forest> coniferous landscape forest, tree layer changes greatly, evenness index and diversity index is more consistent sort, but large differences in the shrub layer.(3)Through the use of cluster analysis,100 woody plant communities in Nanjing urban space are classified:Most of the sample area clearly focused on four major parts in the tree, and concentration of sample area can be seen from plate, the same function type or completion time distribution of sample plots in the plate position, there are obvious concentration. Euclidean distance is 6, could be divided into dominant sample area 55 groups, all kinds of sample area and the function of green space types of the flock, built also has a more obvious relationship. Clustering analysis method used for classification of artificial plant community also has certain significance, divided by the clustering groups in addition to the associated with the dominant species, also built by the function of green space types, time, location, etc.This study from the species composition and diversity characteristics, artificial community type’s three sides analyzed woody plant community in Nanjing urban green space, and in order to construct ecological urban green space of woody plant community to provide the reference.