rapport d'expertise pour l'UNEP (Programme des Nations Unies sur l'Environnement)The work of the expert group was based on peer-reviewed scientific or technical literature, supplemented by peer-reviewed examples of practice. Section II provides an overview of the processes that underpin ecosystem functions in relation to hydrology, and how these support the delivery of ecosystem services. Specific examples of these relationships, and how they can be managed in practice, are elaborated for agricultural systems and cities in section III . Social and economic aspects of this topic are largely self-evident and briefly discussed in section IV. Section V discusses the recent international policy landscape, highlighting the profile of this topic in the outcomes of the United Nations Conference on Sustainable Development 2012 (Rio+20). It also discusses some institutional constraints to managing the biodiversity-water cycle relationship and identifies simple ways of enabling more rapid uptake of biodiversity-based solutions to water-related problems. Section VI identifies the immediate opportunity available to the Conference of the Parties to strengthen cooperation and partnerships on this subject as a means to enhance implementation of the Strategic Plan for Biodiversity (2011-2020)