Research On Characteristics Of Structure Of Plant Communities And Optimal Regulation In Urban Green Space

Based on keeping the number of urban green space continue to increase, how to improve quality of green space and maximize its ecological function is a key issue worth thinking and researching. The health and stability of plant communities is an important standard to measure the quality of urban green space. Whether the structure of plant communities is reasonable or not plays a key role in maintaining health and stability of plant communities.In recent years, many scholars focused on the the ecological service and function of plant communities and has obtained many encouraging results, but the study on the structure of plant communities in urban green space is relatively weak.The reasonable structure of plant communities can not only enable the plant to maximize the use of resources and space, but also promote individual growth and ecological functions and benefits of plant communities efficiently. Therefore, research on the structure of plant communities in urban green space can provide a scientific and reasonable technical reference to the construction of green space in urban and rural areas and have important theoretical value and practical significance.In this thesis, through the field investigation, measurement and analysis of structure of plant communities in urban green space of Shanghai, the theory of plant communities,the theory of plant physiology and ecology, the theory of landscape and architecture are combined and applied to the process of construction and management of plant communities in urban green space.This study includes seven parts. First, the background, purpose and significance of the study of the structure of the plant communities in urban green space are discussed and scientific problems and assumptions are put forward; Second, the historical research of the structure of plant communities in urban green space at home and overseas are briefly compared and the valuable research theory, experience and methods are summed up; Third,the characteristics of the structure of plant communities are summarized; Forth, the key features of the construction of the structure of the plant communities are concluded from the aspect of density(feature of number), pattern(feature of relationship),form(feature of appearance) and process(feature of dynamics); Fifth, based on the survey of the structure of the plant communities in Shanghai, the characteristics of the structure of plant communities in urban green space are analyzed; Sixth, the dynamic mechanism of the evolution of plant communities are discussed from the perspective of the formation, organization, adaptation and development of the structure of plant communities; At last, strategies and methods are put forward to give valuable suggestions to construction and management of plantcommunities.The research findings are summarized as belows.In the first place, the growth models of common landscape plants in urban green space(DBH&CW and DBH&H) are established. Based on the unit of DBH which is the most common in the process of plant design, prediction analysis of space scale of plant communities of various types in urban green space can be carried out accurate in order to provide guidance for scientific and rational design, construction and management of plant communities in urban green space.In the second place, through comparing by characteristics of canopy structure and light environment in different types of structure of plant communities and sorting and classifying by parameters of canopy closure, PPFD and LAI, it can provide reference for the construction of stratified structure of plant communities.In the third place, based on analyzing the linear plant communities(plant community of road greenbelt), the characteristics of change of structure of plant communities in different planting pattern are concluded and canopy line of plant communities in different types are analyzed quantitatively.Furthermore, the relevant laws of dynamic changes of structure of plant communities in urban green space are summarized through dynamic monitoring of fixed sample plot.In addition, based on the analysis of mechanism of formation and self-organization, the dynamic mechanisms of the evolution of the structure of plant communities in urban green space are concluded.At last, the strategies and methods about the construction of landscape plant communities and optimal management in the urban green space are discussed from the aspects of optimal density, dynamic process and ecological relationship.