Ecological status of the Tuscan Archipelago rocky habitats assessed by the MedSens index

MedSens is a biotic index developed to provide information on the environmental status of subtidal rocky coastal habitats, based on data collected by trained scuba diver volunteers using the Reef Check Mediterranean Underwater Coastal Environment Monitoring (RCMed-UCEM) protocol. The index is based on 25 selected species, incorporating their sensitivities to the pressures indicated by the European Marine Strategy Framework Directive (MSFD) and open data on their distributions and abundances. The large availability of data collected by volunteers using the RCMed-UCEM protocol offered the opportunity to assess the ecological status of the subtidal coastal rocky habitats, including the coralligenous reefs, in the Tuscan Archipelago National Park. MedSens index was applied along the coasts of the National Park Islands’ (Capraia, Elba, Giannutri, Giglio, Gorgona, Montecristo and Pianosa), providing the mean sensitivity of the assemblages to the physical, chemical, and biological pressures, as well as the overall mean sensitivity of the occurring assemblages. MedSens can help conservationists and decision-makers identify the main pressures acting in these coastal habitats, as required by the MSFD, supporting them in implementing appropriate marine biodiversity conservation measures and better communicating the results of their actions.