Urban ecosystems as 'natural' homes for biogeographical boundary crossings

Urban ecosystems have long been neglected in ecological theory and urban politics, with their respective tendencies towards anti-urbanism and exclusive humanism. As Hinchliffe et al. argue, ‘not pure enough to be true and not human enough to be political, urban wilds have no constituency’ (2005, 645). Ecologists have tended to focus on ‘pure’ places, free from and defined in relation to the degradation of the urban environment. Meanwhile urban theorists have conceived of cities as human spaces, only occasionally figuring nonhumans as resources, risks or infrastructure. Environmental geography has made notable advances in physical and social aspects of (for example) urban climate and hydrology, but (with a few exceptions) has not been particularly concerned with the ecology of urban ecosystems (see Moffat and Hutchings 2007; Selman 2000).