The future of urban biodiversity research: Moving beyond the 'low-hanging fruit'

In this era of rapidly urbanising human populations, urban practitioners are under increasing pressure to create resilient and sustainable cities and towns. Urban ecologists currently have a unique opportunity to apply solid, evidence-based research to help create biodiversity-rich and sustainable cities and towns for the future. Unfortunately, there is currently a mismatch between the questions planners, designers and decision-makers are asking urban ecologists that would allow them to improve the biodiversity outcomes in urban areas, and the questions urban ecologists must ask to contribute to the development and application of the science of urban ecology. For a number of reasons, urban ecologists over the past 25 years have primarily focused on describing the patterns of biodiversity in cities and towns using broad, aggregate predictor variables (e.g., distance to city center, land-use, percent cover of impermeable surfaces and vegetation, etc.). We refer to these results as 'low-hanging fruit'. If the discipline of urban ecology is going to provide the necessary information to inform actions to preserve and enhance urban biodiversity, we need to move beyond place-based research, and work towards the development of confirmed generalizations regarding the relationship between the structure and function of urban ecosystems and biodiversity. We propose three essential strategies for achieving this refined understanding: 1) defining the study window to place the study into a broader global context, 2) collecting and using more explicit question-driven measures of the urban condition in order to improve our understanding of urban ecological drivers, as well as recording more detailed ecological responses to provide insights into the ecological mechanisms underlying an observed response, and 3) expanding studies to include multiple cities, regions and countries. These strategies will help to expedite the ability of urban ecology to contribute to the creation of biodiversity-rich, healthy, resilient cities and towns.