Who Really Wants an Ambitious Large-Scale Restoration of the Seine Estuary? A Strategic Analysis of a Science–Policy Interface Locked in a Stalemate

The development of ecosystem knowledge is an essential condition for effective environmental management but using available knowledge to solve environmental controversies is still difficult in "real" situations. This paper explores the conditions under which ecological knowledge could contribute to the environmental strategies and actions of stakeholders at science-policy interface. Ecological restoration of the Seine estuary is an example of an environmental issue whose overall management has run into difficulties despite the production of a large amount of knowledge by a dedicated organization, GIP Seine Aval. Thanks to an action-research project, based on a futures study, we analyze the reasons of these difficulties and help the GIP Seine Aval adopt a robust strategy to overcome them. According to our results, most local stakeholders involved in the large-scale restoration project emphasize the need for a clear divide between knowledge production and environmental action. This kind of divide may be strategic in a context where the robustness of environmental decisions is strongly depending on the mobilization of "neutral" scientific knowledge. But in our case study, this rather blocks action because some powerful stakeholders continuously ask for more knowledge before taking action. The construction and analysis of possible future scenarios has led to three alternative strategies being identified to counter this stalemate situation: (1) to circumvent difficulties by creating indirect links between knowledge and actions; (2) to use knowledge to sustain advocacy for the interests of each and every stakeholder; (3) to involve citizens in decisions about knowledge production and use, so that environmental issues weight more on the local political agenda.