Current conservation status of autochthonous seagrasses in the Mediterranean Sea: a systematic review

Seagrasses are globally declining. They form important ecosystems, providing food and shelter for other marine organisms as well as services such as protection from coastal erosion and water quality regulation. For these reasons, their conservation should be of primary concern. A critical review was conducted to determine whether conservation efforts for autochthonous marine angiosperms in the Mediterranean Sea were consistent with their status based on their distribution, habitat, population dynamics, main threats, and conservation strategies used for each one. In general, seagrasses are declining in the Mediterranean, and conservation efforts vary greatly depending on the species. Posidonia oceanica (L.) Delile and Cymodocea nodosa (Ucria) Asch were the species that were investigated the most between 2000 and 2020. On the other hand, little information about Ruppia maritima L. was available. The in situ conservation strategies implemented for these species are considerably more advanced than the ex situ. The highest level of legal protection is given to P. oceanica, whereas the remaining species are mainly protected by efforts aimed at all seagrasses in general. Not many studies were published on the ex situ conservation strategies, particularly those aimed at their long-term preservation in gene banks, which were restricted to Zostera marina L., Ruppia cirrhosa (Petagna) Grande, and R. maritima.