Urban Ecosystem Services: A Review of Definitions and Classifications for the Identification of Future Research Perspectives

Thanks to many initiatives, such as the Millennium Ecosystem Assessment (MEA), The Economics of Ecosystems and Biodiversity (TEEB) and EU target for 2020 on Biodiversity, the topic of ecosystem services has received even more attention both in the academic and political debate. On the contrary, the research on urban ecosystems and urban ecosystem services has yet been relatively modest compared to other ecosystems, like wetlands or forests. However, the relevance of topic requires more efforts in this field also because, in most cases, urban ecosystem services have been studied individually, without considering their role in governance and planning processes. In this context, the present paper has the aim at giving a perspective of the state of the art of the research on urban ecosystem services with a focus on the different definitions and classifications emerging from the literature, as well as of examples of indicators for their valuation. The work highlights the gaps in the research to support the definition of future research perspectives and analysis, in particular for the adoption of valuation approaches able to guide the decision-making process in urban areas and for ensuring the consideration of urban ecosystem services in spatial planning policies and actions.