The new global urban realm: Complex, connected, diffuse, and diverse social-ecological systems

Melissa R. McHale, NC State University
Steward T.A. Pickett, Institute of Ecosystem Studies
Olga Barbosa, Universidad Austral de Chile
David N. Bunn, Wits Rural Facility
Mary L. Cadenasso, University of California, Davis
Daniel L. Childers, Arizona State University
Meredith Gartin, Arizona State University
George R. Hess, NC State University
David M. Iwaniec, Arizona State University
Timon McPhearson, The New School
M. Nils Peterson, NC State University
Alexandria K. Poole, Elizabethtown College
Louie Rivers, NC State University
Shade T. Shutters, Arizona State University
Weiqi Zhou, Research Center for Eco-Environmental Sciences Chinese Academy of Sciences


Urbanization continues to be a transformative process globally, affecting ecosystem integrity and the health and well being of people around the world. Although cities tend to be centers for both the production and consumption of goods and services that degrade natural environments, there is also evidence that urban ecosystems can play a positive role in sustainability efforts. Despite the fact that most of the urbanization is now occurring in the developing countries of the Global South, much of what we know about urban ecosystems has been developed from studying cities in the United States and across Europe. We propose a conceptual framework to broaden the development of urban ecological research and its application to sustainability. Our framework describes four key contemporary urban features that should be accounted for in any attempt to build a unified theory of cities that contributes to urban sustainability efforts. We evaluated a range of examples from cities around the world, highlighting how urban areas are complex, connected, diffuse and diverse and what these interconnected features mean for the study of urban ecosystems and sustainability.