Spatio-temporal assessment of urbanization impacts on ecosystem services: Case study of Nanjing City, China

Rapid urbanization is a global phenomenon that has altered many ecosystems, causing a decline in many ecosystem services, generating ecological risks such as water shortages, air pollution, and soil pollution. Here, we present a conceptual framework quantifying how urbanization influences the ecosystem services in a typical city (Nanjing) of China. Between 2000 and 2010, we separated the city into three urbanization categories (developing urban, developed urban, and rural areas) and quantified the status of six critical ecosystem services (food supply, carbon sequestration, soil water storage, air pollution removal, habitat suitability, and recreation potential). Our results show that urbanization significantly impacted all ecosystem services, with detected changes in ecosystem services being spatially heterogeneous due to urban expansion and population mobility. Developed areas contained greater amounts of green infrastructure, which improved carbon storage and reduced air pollution. In contrast, the rapid expansion of urban and industrial land in developing urban areas led to lower food supply, carbon sequestration, soil water storage, and habitat suitability. The expansion of rural residential areas led to lower soil water storage, carbon sequestration, and food supply, while greater amounts of abandoned cropland resulted in increased carbon sequestration, but decreased food supply in rural areas. Analysis of the interactions between pairs of ecosystem services identified urbanization development problems, including abandoned cropland and the expansion of rural residential land. Lastly, we proposed four key urban planning measures to mitigate the loss of ecosystem services during rapid urbanization. Acquiring quantitative knowledge about how rapid urbanization drives changes to ecosystem changes may help guide sustainable urban planning with respect to ecosystem service use, urban development, and human welfare benefits. (C) 2016 Elsevier Ltd. All rights reserved.