Meta-analysis reveals the effectiveness and best practices for the iconic Mediterranean seagrass restoration

Seagrass forest restoration programs have become a global priority to reverse their decline and regain their ecosystem services. However, defining the restoration effectiveness has remained controversial, probably due to the wide selection of procedures experienced mainly on short-term periods and local scales. Here, scientific literature from 40 years of experience on experimental works and active restoration interventions of the Mediterranean foundation seagrass Posidonia oceanica has been systematically summarized through a meta-analysis. Twenty-five variables concerning the characteristics of the site selection, procedural context, and plant performance evidenced the best practices for the seagrass restoration. Results have evidenced the importance of the correct selection of the donor and receiving site, the use of plagiotropic cuttings bearing at least three shoots, and the need of monitoring the total extent of restored area for long term periods, considering more than one plant trait to define the plant performance. Higher biological levels should be also considered to estimate the recovery of the habitat structure and ecosystem functioning.