The endangered coral Cladocora caespitosa in the Menorca Biosphere Reserve: Distribution, demographic traits and threats

Abstract

Information on the distribution, population traits and conservation status of the endangered coral Cladocora caespitosa is still missing for most of its distribution area. As prompted throughout conservation assessments and red lists, obtaining such information is a priority in the current context of generalized decline of benthic communities in the Mediterranean Sea. We assessed these topics in the main C. caespitosa populations (n = 18) thriving throughout UNESCO's Menorca Biosphere Reserve (MBR), which includes the largest marine Biosphere Reserve in the Mediterranean Sea. The MBR harbours an arrange of C. caespitosa populations of great interest, with a good representation of the contrasted environmental conditions that this long-lived coral is able to thrive in. Although average coral cover falls into the lower range compared to other Mediterranean populations, it is the ubiquity of the species along Menorca's coastline that differentiates this location from others described to date. Warming-related mortality can be considered the main threat to this species in the MBR, showing an average colony necrosis of ∼30%. Nevertheless, special attention should also be paid to other potential threats derived from human activity, such as pollution and coastal development. This study should be used as a baseline to implement conservation and management actions in the MBR, including a long-term monitoring programme.