Posidonia oceanica restoration: bibliographic review and data field analysis

Abstract

Seagrasses like Posidonia oceanica provide a wide range of benefits for the ocean and for the planet. Efforts in conservation and restoration have increased in the last 20 years to preserve P. oceanica meadows; a plenty of works have been conducted to develop restoration and planting actions as a way to offset the regression of this seagrass in the Mediterranean Sea. We here compile the information on these studies to make a bibliographic review. Additionally, we collected seeds in Formentera (Balearic Islands, NW Mediterranean Sea) and cultured them for 1-2 months to measure them. Measuring these seedlings allowed us to compare annual data to prove seedlings annual size variability. As a way to calculate the growing rate in 1-year-old seedlings, we measured the leaves of seedlings planted last year. The review results showed that seedlings grow better on dead matte and rock covered with algae in calm waters with moderate depths. The PERMANOVA and Kruskal-Wallis tests showed significant differences in seedlings size between the two years of this study. All the means of the measurements were higher in 2021 than in 2022, and the n-MDS support this, showing significant differences. The growth rate showed a value of 9.8 cm year-1 in leaf length and 0.3 cm year-1 in leaf width in 1-year-old seedlings. More results and strong conclusions are necessary and will be obtained by extending the study for more years. Furthermore, with intensive and integrative work more gaps in knowledge could be filled in the upcoming years