Application of the ecosystem services approach to support the conservation of Mediterranean octocorals

This thesis, conducted in collaboration with Laboratoire d’Ecogéochimie Environments Benthiques (LECOB, SU-CNRS) in Banyuls-sur-Mer, aims to assess the ecosystem services (ES) provided by three Mediterranean gorgonians, threatened by climate and local impacts: Corallium rubrum, Paramuricea clavata, and Eunicella singularis. ES are the benefits ecosystems provide to humans and are categorized in provisioning, regulating, supporting, and cultural in line with the Millennium Ecosystem Assessment. Through a literature review, 42 papers were selected to assess Mediterranean gorgonians ES provisioning evidencing that they provide a range of fundamental ES. To evaluate the cultural ecosystem services (CES), questionnaires were developed and administered to visitors of the Biodiversarium aquarium and the Plongée Bleue diving center in Banyuls-sur-Mer during the summer of 2023. Results of the literature review showed an increasing focus on ES, particularly since 2016, indicating a growing awareness of their ecological and social value. Results of CES evaluation indicate that aquarium visitors show a greater interest in the educational service, while divers prefer services of aesthetic nature. This difference can be because the aquarium is geared towards education and outreach, aiming to provide visitors with an understanding of the marine ecosystem and its biodiversity, while divers enjoy close contact with gorgonians during their dives, which may explain their greater interest in aesthetic services. These differences emphasize the importance of considering the context and purposes of activities when evaluating CES. No relevant differences in CES preferences were found depending on participants' gender. Overall, the thesis results can be used to develop ecological indicators of gorgonians ES provisioning and guide future research efforts on the topic to support gorgonians’ conservation and management actions in the Mediterranean Sea.