Ecological quality assessment of urban green spaces based on landscape metrics: A case of Nanjing, China

Hao Xu 

COMPUTER MODELLING & NEW TECHNOLOGIES 2014 18(12A) 384-391

College of Landscape Architecture, Nanjing Forestry University, Nanjing, China

China’s ongoing urbanization is having a profound effect on the environment, and Nanjing, as one of the most important metropolitan areas of the city cluster in China’s Yangtze River Delta, is not immune to this development; as such, it is greatly affecting the scale and structure of its urban green spaces. An ecological quality assessment of Nanjing’s green spaces is fundamentally significant to appropriate spatial planning and the implementation of sustainable development ideas. This study uses ALOS (Advanced Land Observing Satellite) remote-sensing image data to map the distribution of urban green spaces in Nanjing, and employs various landscape metrics to analyze and evaluate the city’s spatial layout and ecological quality. Results of the study reveal that the distribution of urban green spaces in Nanjing is highly uneven, with most located in suburban areas and few within the city’s core. Green space within the urban area is highly centralized around the Zijin Mountain woodlands, while green space in the suburbs is highly dispersed and fragmented. A large proportion of Nanjing’s green space comprises farmlands, primarily distributed on the outskirts of the city and in the suburbs. The amount of farmland, however, is continuously decreasing, as the land is being used in the ongoing urban development. This is expected to rapidly lower the ecological quality of the region’s green spaces. In order to improve the ecological quality here, both recreational and ecologic functions of green space should be considered during the phases of spatial planning. It also is suggested that more core green spaces be built, such as ecological country parks, to increase the ratio of woodlands, enhance the management of ecological spaces in suburban areas, establish ecologic greenways, and strengthen the connectivity of green spaces.