<p>Rapid urbanization caused a massive loss of natural habitats and seriously changed urban natural ecosystems. Ecological network, a spatial concept of ecosystems, maps the most valuable areas that provide multiple ecological goods and services for human demands. Ecological network has long been adopted worldwide for improving urban ecological environment under the scenarios of rapid urbanization. However, Little researches focused on changes in ecological networks and their effects on urban ecosystem. It is important to investigate the trends in ecological network changes, clear its relationship with human activities and policies for guiding sustainable economic and social development. The study aimed to analyze the relationship between the changes in ecological networks and human activities, regional policies as well as environmental changes, and to establish new ecological networks that meet the human demands of ecosystem services, in China&#8217;s three typical urban agglomerations, including Beijing-Tianjin-Hebei (BTH), Yangtze River Delta (YRD), and Pearl River Delta (PRD) from 2000 to 2015.This study used the variation of habitat quality index, ecosystem carbon stock, PM<sub>2.5</sub> and supply-demand of ecosystem services to measure the eco-environmental effects of ecological network changes under complex physical and socio-economic circumstances. Meanwhile, it established the new ecological networks based on the human-being demand of ecosystem services calculated by real-time population distribution, accessibility, and land development index, trying to optimize the land spatial patterns and ecosystem management in urban agglomerations.&#160;The results showed that a lot of areas of ecological networks had vanished into dryland, urban land and other developed land from 2000 to 2015, resulting from urban expansion, industrial development and regional land policies. The degradation in ecological networks caused a significant increase of PM<sub>2.5</sub> and decrease of habitat quality index and ecosystem carbon stock. And the spatial imbalance in the supply-demand of ecosystem services was shrinking to varying degrees, due to different regional ecological protection policies. There were regional spatial differences in the establishment of new ecological networks. However, the closer to central cities of each agglomerations, the human demands of ecosystem services and the need of strengthening the preservation ecosystems were more critical. This study contributes to the identifying the role of human activities on ecological processes and provides a scientific reference for the use of ecological network as the basis of the regional development plans. It is necessary to relieve the dilemma between the urban growth and ecosystem protection.</p>
Cost-benefit analysis of ecological networks assessed through spatial analysis of ecosystem services
