Urban ecological infrastructure: an integrated network for ecosystem services and sustainable urban systems

The sharp increase in global urban population and rapid expansion of impervious urban surfaces is raising concerns over more than just the quality of human life; researchers are also worried about ecosystem services and the stability and security of urban ecosystems and the infrastructures. In this paper, we define “urban ecological infrastructure” and propose an integrated framework in which the infrastructure network provides ecosystem services and sustainable urban systems despite changing landscapes and climate. We define the urban ecological infrastructure (UEI) as an organic integration of blue (water-based), green (vegetated), and grey (non-living) landscapes, combined with exits (outflows, treatment, or recycling) and arteries (corridors), at an ecosystem scale. The UEI framework represents the biotic and abiotic interactions within an ecosystem, and stresses an integrated relationship between artificial and natural systems. It links the grey, blue, and green infrastructures, and integrates them via both exits and arteries. Its insights can help to improve the circulation and reuse of resources throughout the urban ecosystem. This comprehensive conceptual framework can facilitate more rational urban development, and can improve urban ecosystem services and regional sustainability. Although understanding the form and function of UEIs is an important first step, innovative strategies are needed to address challenging obstacles such as rigid thinking, institutional fragmentation and inflexible policies. New thinking and innovative ways of acting will be required to provide a more resilient, stable, and sustainable urban system.