Urban vacancy and land use legacies: A frontier for urban ecological research, design, and planning

Around the world, many urban districts and some entire cities are dominated by vacant and abandoned property. Former uses of these properties range from heavy industry to residential neighborhoods, and each bears many potential legacies of past uses, including: introduction of contaminants that may threaten the health of humans and other species, engineering of land and infrastructure that may undermine hydrological ecosystem services, and introduction of species including invasives. While the ecological functions that characterize vacant urban lands have been only partially investigated, the legacies associated with their past uses are known to affect ecosystem services. In addition, changed industries, weakened economies, arcane financial systems, population migration, and aging resident populations have left many people living in the midst of this vacancy, with clear implications for human health and safety. Since market demand is weak in highly vacant districts, social capital may be particularly important to protecting quality of life and ecosystem services. New design and planning approaches should be informed by urban ecological knowledge that is synthesized with social and cultural understanding of residents' perceptions and values. Interest in urban agriculture, green infrastructure, and open space planning for vacant urban lands is burgeoning. However, without adequate knowledge of highly vacant districts as socio-ecological systems, design and planning may have unintended consequences for human health, water quality, adaptation to climate change, and a panoply of other ecosystem services. Research questions and design and planning applications require a transdisciplinary approach to address highly vacant urban districts with legitimacy and relevance.