Abstract
Posidonia oceanica meadows are among the most valuable coastal ecosystems in the Mediterranean Sea, providing key ecological functions and socio-economic benefits. Despite conservation efforts, these meadows declined markedly throughout the late 20th century due to cumulative human pressures, although their condition has stabilised more recently under protection, and natural recolonization has even begun in some areas. In this context, active restoration through transplantation has expanded considerably, particularly in response to recent policy initiatives, and is now contributing to the recovery of these ecosystems. However, long-term monitoring to assess active restoration success remains scarce. This study revisits one of the earliest P. oceanica transplantation interventions, initiated in 1996 in front of the tourist harbour of Rapallo (NW Mediterranean), and evaluates its status after nearly 30 years. Surveys conducted in 2019 and 2024 confirmed the persistence of the transplanted meadow. The restored area increased from approximately 20 m2 at establishment to 26.9 m2 in 2024, and shoot density reached values comparable to well-developed natural meadows in the region. The observed long-term structural stability highlights the need to assess restoration outcomes over decadal timescales. This case study also suggests that fine-scale site conditions, including hydrodynamic shelter and adequate light availability, can strongly influence long-term restoration success.