Urban invasions: non-native and invasive species in cities

Non-native and invasive species of plants and animals represent a major threat to global biodiversity and associated ecosystem services. Developing an understanding of processes, impacts and controls of invasions is an important challenge for biogeographers and ecologists. Within the rapidly-expanding knowledge of species invasions, urban ecosystems remain curiously under-explored. Despite the paucity of research it is known that cities, with their unique socio-ecological and environmental characteristics, exhibit high frequencies of introductions of flora and fauna. These invasive species in cities result in economic and quality of life impacts on residents due to both high human population densities and abundant built infrastructure. Unfortunately, species control and management efforts can be hampered due to complexities of urban land use and governance. In this article we review key aspects of species invasions in cities and highlight areas for future research.