An IMEDEA's study analizes posidonia replantation techniques

A team of researches of the Mediterranean Institute for Advanced Studies (IMEDEA, CSIC-UIB) and of the MedGardens Initiative of the Cleanwave Foundation has identifies more efficient, profitable and respectful with the Mediterranean planting techniques to boost the recovery or the posidonia meadows.

The study, carried out by the Dra. Gema Hernán, the Dra. Fiona Tomas (IMEDEA, CSIC-UIB) and the MedGardens team (Cleanwave Foundation), analizes different replantation techniques for this iconic plant of the Mediterranean. The research, carried out in the bays of Formentor and Portocolom (Mallorca), not only compares its ecological success, but also its practical aspects such as the cost, logistics and environmental impact, identifying the most promising option to favor natural recovery of the degraded meadows. 

The Posidonia oceanica, protected by European, Spanish and Balearic law, forms one of the most valuable ecosystems of the Mediterranean. These submarine meadows acts as authentic "blue lungs": they produce oxygen, protect the coast before erosion and keep great carbon quantities, helping mitigate climate change. However, human pressure, non-discriminated mooring, pollution and sea warming han provoked an important regression of these habitats 

The replantation of fragments of Posidonia oceanica is seen as a key tool to boost the degraded meadows recovery, although until now it was expensive adn had limited success. The research compares, for the first time, different anchoring methods -methalic clamps of gardening, bamboo sticks, bigger clamps and artisanal sandstone stakes-, evaluating its ecological efficiency as well as cost, supply, carbon footprint and logistics practical factors. 

After two tracking years, results show that gardening clamps and bamboo sticks are the most efficient and sustainable options, with survival taxes of up to a 94%, under cost and less environmental impact. Big clamps, although they favor growth of more developed parts, present major logistics limitations, since they require most voluminous samples, difficult to find and less profitable. 

Altogether, more simple and light methods are a promising way to expand restoration to a major scope without committing ecological results. 

“Our research shows that restoring Posidonia oceanica  meadows can be more affordable and respectful with environment, integrating ecological, economical and logistics criteria. This is key to design viable restoration and sustainable projects on the long term", the authord of this study point out. 

This research is inside the Restoration Law of Nature of the UE and in the decade of the United Nations regarding Ecosystems Restoration (2021–2030), reinforcing the importance of carrying out these actions legally, responsibly and strategically. The work highlights the importance of carrying our long tracking after plantation, since the first years there were slow growth dynamics and a certain material loss. However, standard survival after two years goes over the 80%, which conffirms the potential of these techniques in shallower areas and protected where Posidonia existed previously. 

Research shows a steo forwards a more integral marine restoration, that does not only aim to recover lost vegetation, but doing it more efficiently, sustainably and adaptable to real conditions of work at sea. This balanced approximation between ecological success and practical viability sets the bases for future recovery actions to a great scope in the Mediterranean and other coastal regions. However, researchers remind that the best strategy is always preserving existing meadows before replanting them.