The science of middle nature: An alternative to urban ecosystem services

There are still no clear and accepted theoretical frameworks for understanding the relationship between humans and their biophysical environment in cities. Common frameworks such as the ecosystem services concept have been imported from natural ecosystem science and are an imperfect fit for understanding built and engineered ecosystems.  We argue that urban ecosystems are well described by the concept of "middle nature" which serves a purpose of “actively transforming nature into culture” (Cosgrove 1993).  From this perspective, a more complete integration of ecology with engineering, planning, architecture, and design offers a path forward.