DINAMICA TEMPORALE DELLE PRATERIE DI POSIDONIA OCEANICA (L.) DELILE (FANEROGAMA MARINA) NELL’AREA DI TUTELA MARINA DI CAPO MORTOLA

TEMPORAL DYNAMICS OF POSIDONIA OCEANICA (L.) DELILE (SEAGRASSES) MEADOWS IN THE CAPO MORTOLA MARINE PROTECTED AREA

Abstract

Meadows of Posidonia oceanica (L.) Delile in the Mediterranean Sea are undergoing a progressive decline due to the combined effects of local and global pressures. In the northwestern Mediterranean, up to 56% of these meadows have already been lost since 1869. This regression favours the colonization by substitute species, such as the invasive green algae of the genus Caulerpa, which can bring profound structural and functional changes in coastal ecosystems. For instance, in the Capo Mortola Marine Protected Area (Western Ligurian Sea), the P. oceanica meadow cover has declined between 1987 and 2002, leading to the appearance of Caulerpa taxifolia (Vahl) C. Agardh. However, recent monitoring showed that, since 2002, C. taxifolia has disappeared while the density of the meadow has remained constant. Our results are consistent with recent studies, suggesting potential resilience of P. oceanica meadows under favorable conditions, although a recovery can be confirmed only with long-term monitoring.