This chapter suggests that understanding the complex relationships between patterns of urban development and the processes that maintain ecosystem function and resilience requires new frameworks and approaches. These frameworks must move from interdisciplinarity to transdisciplinarity to better uncover mechanisms that drive urban dynamics, including urban ecosystem service supply and demand, patterns of social inequity, and the role of ecosystems in supporting resilience and adaptation to climate change. To navigate towards an integrated ecology for cities and sustainable futures, cities must be examined as integrated social–ecological–technological systems that can drive the development of a fundamentally transdisciplinary urban systems science. Cities are complex adaptive systems made up of interconnected social–economic–political systems, ecological–biophysical–climate systems, and technological–infrastructure systems. Ecology in cities frequently examines how urban development affects organisms and biophysical characteristics of the ecosystem in analogous patches along urban–rural gradients.