Beijing had a rapidly urbanization from 1993 to 2013. It is very impotent to assess the degree of urbanization in Beijing and how its impact on ecosystem services. This study presents an urbanization index system of Beijing City. It includes four categories and 18 indicators of the population urbanization, economic, social and spatial urbanization.
Results/Conclusions
The urbanization index system of Beijing City rises from 0.1166 in 1993 to 0.4522 in 2003 then rose to 0.8910 in 2013. These showed significant positive correlation with the population urbanization index (R2=0.979). Each subsystem of urbanization index system also exhibit different characteristics. Social urbanization is the mainly factor in 1993 to 2001, its contribution to Beijing urbanization over 37.21%. Spatial urbanization is the mainly factor between 2002 and 2009, its contribution in Beijing urbanization more than 31.91%. population urbanization is the mainly factor from 2010 to 2013, its contributed more than 27.5%. The contribution of economy urbanization is rising, and it reached 25.67% in 2013.
Beijing city had developed rapidly in 1993-2013. The built-up area is expanding continuously. The area of forest ecosystem, shrub ecosystems, wetland ecosystems, and agro-ecosystems reduced, but the area of grassland ecosystems, wildland ecosystems, and built-up area increased continuously. From 1993 to 2013, the area of grassland ecosystem increased by 22.99%, the wetland ecosystem decreased by 24.14%, agricultural ecosystems decreased by 14.84%, built-up area increased by 72.67%. The built-up area is expanding rapidly, and it main transformed by farmland and wetlands.
The ecosystem services of Beijing City also have largely changes. The fixed amount of carbon per unit area had an increasing trend of 10.14, 10.59, 12.15 g / (m2a) in 1993, 2003, 2013 respectively. the amount of carbon fixed also increased from 0.17 to 0.20×108 t in 1993 and 2013, respectively. Water supply of per unit area increased from 887.70 to 2802.73 m3 ha. The amount of water supply also increased from 14.57 to 45.99×108 m3. The increase rate of the amount of water supply in 2003-2013 is faster than the previous decade. The amount of erosion control unit area is increases from 42.69 to 75.36 t/ha, the amount of erosion control increased from 0.70 to 1.24×104 t from 1993 to 2013 in Beijing City.
Over the past 20 years, Beijing City had a rapidly growing urbanization. however the ecosystem services has continued to increase. These mainly attributed to the implementation of biodiversity conservation policies of Beijing City.