Application of the Ecosystem Service Concept to a Local-Scale: The Cases of Coralligenous Habitats in the North-Western Mediterranean Sea

In an era when we witness the erosion of biodiversity it is essential to understand the benefits provided by ecosystems and find ways to maintain them. The concept of ecosystem service has been applied in this perspective, but mainly in large-scale surveys and on terrestrial ecosystems. The primary objective of this project is to validate the inclusion of the concept of ecosystem service as a useful input to local (small-scale) community decision making in the marine environment. A second objective is to define the beneficial services provided to local areas by the coralligenous habitats. The application of the concept of ecosystem service at a local scale is more appropriate to local regulatory and management issues. This research was focused on the complex and threatened coralligenous habitats, about which the benefits and services provided are relatively little understood. To address these issues and get around the paucity of prior research, we collected the opinions of 43 experts for two marine sites (Bay of Marseille and Port-Cros National Park) on 15 services using interviews, an online questionnaire and workshops. This work validated 10 services: the most evident were "food", "diving sites", "research" and "inspiration". We also showed that even in very close-by sites, slight differences in the bundle of services may occur, and we highlighted knowledge gaps especially concerning those services (so-called regulating services) that help to regulate environmental impacts of other phenomena. This work concluded that there is a strong need to employ a referential frame to identify and then estimate services based on local criteria such as: geographical and temporal scale, size of the population of beneficiaries, value of the benefits, and state of ecosystem well-being. These results are a basis for further evaluation of these ecosystem services and can indicate their positive contribution to local decision-making concerning the regulation and management of coralligenous habitats.