From ecological relevance of the ecosystem services concept to its socio-political use. The case study of intertidal bare mudflats in the Marennes-Oleron Bay, France

Assessments based on monetary valuation of ecosystem services have been increasingly used as a tool to highlight the connection between ecosystems and society. The dissemination of this approach is leading to difficulties and ambiguities related to the use of such assessments in the socio-political realm. Such limits can be stressed using the case study of intertidal bare mudflats. These coastal habitats indeed provide many ecological functions several being related to the high production of benthic microalgae but also remain poorly known for some other aspects. The major users of these habitats (i.e. oyster farmers) are still unaware about the trophic role of benthic microalgae, limiting contingent valuation survey methods. Moreover, economic valuation cannot take into account the potentials of mudflats (i.e. undescribed functions) like positive feedbacks related to shellfish farming and provision of bioactive compounds. The lack of physical boundaries in marine systems also strongly reduces the effectiveness of assessments. Lastly, there are concerns that monetary valuation can lead to a commodification of the nature or to the economization of the environment (e.g. appropriation of the environment by users, creation of artificial thresholds). The evaluation of the functions of a socio-ecosystem should not only be restricted to a monetary assessment of its ecosystem services, as this framework may be more reductive than integrative. Some other descriptors not based on currencies should be used for ecosystem description.