Green space pattern changes and its driving mechanism: a case study of Nanjing metropolitan area

With the urbanization process advancing, green space plays an increasingly prominent role in maintaining ecological environment and improving living quality, which is of great significance to regional sustainable development. Based on the land use data from 2000 to 2015, this study revealed the spatiotemporal change characteristics of green space in Nanjing metropolitan area applying spatial analysis methods in GIS. And from three aspects of economic driver, government regulation and social development, an econometric model was constructed to analyze the driving mechanism. The results showed that the green space in Nanjing metropolitan area is concentrated in outer suburbs and suburbs but scattered in central urban area on a small scale, with obvious spatial gradient characteristics. The overall scale of green space has decreased, with the most severe reduction in suburbs, followed by outer suburbs. The evolution model was mainly dominated by outspread shrinkage in sub-cities and the new cities and endocytosed shrinkage in the central city and sub-cities, supplemented by a small number of perforated shrinkage and corridor-cut shrinkage in new cities. The study also found that the changes of green space were driven by many factors; the economic drivers such as industrial development and economic growth were the leading forces for the reduction of green space, and the effect of social development was relatively not significant, while government policies such as planning policies and public investment had a certain positive effect on the protection and construction of green space.