The importance of research on cities as urban ecosystems has increased in recent years. Cities comprise complex interactions between humans, flora, fauna, materials, built infrastructure and climate factors. The health of cities as complex ecosystems is determined by how socio-ecological systems are interconnected and resilient to natural dynamics. Key to our research on ecosystems is addressing challenges of working at the intersection of natural systems, communities and the built environment. A particular focus is given to practice-driven research on water ecosystems and green infrastructures in relation to climate change, integrating natural environments with built environments, restoration through creative engagement, and innovations in design and planning for regeneration.