Seagrass transplantation

Posidonia oceanica is an endemic and strictly protected seagrass that is also called The forest of the Mediterranean. It is estimated that one square meter produces 14 liters of oxygen per day, and in addition, it is a source of food and habitat for many species that seek shelter, spawn and reproduce among its leaves. More than 400 plants and about a 1000 animal species live in Posidonia meadows. However, it is highly endangered due to a series of human activities such as anchoring.

Figure 1. Monitoring of the donor meadow of flowering Posidonia.

Considering that Posidonia is more and more endangered every day, we decided to help it through the Interreg Italy-Croatia SASPAS project. One of the SASPAS goals  is a pilot project for the transplantation of seagrass. In the fall of 2019, for the first time on the eastern side of the Adriatic, in the Kornati National Park in Kravljačica bay, a Posidonia meadow was transplanted. The Kornati National Park, unique in the world for its branched, stone labyrinth of islets and the sea that is every diver’s dream, attracts a large number of sailors precisely because of its beauty.

Figure 2. Transplants on supports made of corn starch.

Before the Posidonia transplantation itself, we carried out the preparation of the field and the first monitoring, or field research in which we determined the state of the Posidonia meadows in certain locations. The transplants, 720 of them, were taken from a healthy meadow in Baluni Bay and attached to supports made of corn starch. These supports have the role of adhering to the rhizome, while the plant takes root and anchors itself in the seabed. Over time, they will completely decompose. This patent, which is biodegradable and harmless to nature and the marine ecosystem, was designed by colleagues from Sicily.

Figure 3. Posidonia rhizomes attached to supports using biodegradable ties.

In order to monitor the progress and success of the transplantation process, meadows were continuously monitored, which showed that the transplantation was successful. After the installation of environmentally friendly anchoring systems in July 2021 in four bays in the Kornati National Park, the transplantation procedure was repeated in October 2021. In Anica bay 600 cuttings were transplanted, which were taken from the donor meadow in Prisliga bay. During this transplantation, the methodology was somewhat different and this time the supports were made of wooden slats, and the Posidonia rhizomes were attached using biodegradable ties.

Figure 4. Divers inspect new transplants.

In July 2021 began the campaign “Become a Posidonia keeper”, which aims to raise awareness among the public, especially sailors, about the importance of protecting and preserving seagrasses, with a special emphasis on Posidonia. You can find out how you can get involved in the protection of this species in the project’s campaign.