Large-scale changes benefiting biodiversity can potentially be achieved through bottom-up influences if city dwellers are motivated to recognize and appreciate native species and feel they can make a contribution to enhancing biodiversity. The structure of this environment and its ability to support biodiversity is the integrated outcome of both top-down (city-level management strategies and decisions) and bottom-up human influences (choices or actions by householders and individuals Kinzig et al., Reference Kinzig, Warren, Martin, Hope and Katti2005).

Humans are both the problem and the solution in urban landscapes. For ecologists these challenges lie in developing an understanding of how these highly modified systems function and respond to urbanization but for conservation biologists the challenges lie primarily in understanding and influencing human attitudes, interests and motivations. The study of biodiversity and ecosystem function in urban areas is now an expanding discipline that poses many challenges. MacDonnell & Pickett ( Reference Macdonnell and Pickett1990) described urbanization as ‘a massive unplanned experiment’, providing ecologists with opportunities to answer questions of general applicability as well as those specific to the impacts of urbanization. Nowhere is this more evident than in the fledgling discipline of urban ecology. He emphasized that conservation biologists need to think in an interdisciplinary way to make progress. In an earlier editorial Adams ( Reference Adams2007) argued for the integration of social science and conservation, despite differences in language and terminology and in traditions of enquiry and methodologies.

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