The winter has seen the start of a pilot project to replant Neptune seagrass shoots torn up by storms. The aim: to test a non-destructive methodology for restoring degraded Neptune seagrass areas. These actions are part of the Blue Lab project, a SUBMON project that seeks to improve the environmental status of the Natura 2000 marine site of l’Albera, in Llançà, where SUBMON has a stewardship agreement with the Llançà Town Council and the Government of Catalonia. The replanting actions are supported by the project Mares Circulares and have the collaboration of the Llançà Town Council, the Cap de Creus Natural Park, the Llançà Fishermen’s Guild, and the local population.

Contrary to other Neptune seagrass replanting methods, where cuttings of shoots from healthy meadows are used, this pilot trial uses recovered shoots that have been naturally uprooted by storms. So far, we have replanted more than 140 Neptune seagrass shoots, selecting the most viable ones and using biodegradable material to fix them on the substrate. Prior to the replanting work, the corresponding authorisation from the Government of Catalonia was processed, as we are handling and operating with a protected species.

As Andreu Dalmau, Project technician, explains, “replanting shoots of a plant such as Neptune seagrass is a complicated task, as it is a very delicate species. Different studies that have been carried out previously have shown a low survival rate of the shoots after 3 years, and it is currently a scientific concern to be able to test different methodologies and carry out long-term environmental monitoring of replanted shoots. For this reason, the project that we are carrying out at SUBMON has three clear goals: firstly, not to affect healthy meadows in order to test replanting methodologies, using only those shoots that could not survive on their own; secondly, to be able to carry out long-term environmental monitoring of the shoots that are replanted within the stewardship area; and thirdly, to involve citizens in the project, not only to recover uprooted shoots but also to use the context of the project to educate and raise awareness about the importance of Neptune seagrass meadows.”

In order to achieve the objectives set, the participation of the local population has been decisive, as they play a key role in the shoot collection process. For this reason, a training session open to the public was held to explain the project and the process of recovering Neptune seagrass shoots, which consists of recovering the shoots accumulated along the beaches and depositing them in an area set up at the Llançà Fishermen’s Guild. A water container was installed there to preserve the shoots until they are replanted. It is worth highlighting the collaboration of the fishermen’s guild, not only in providing the space, but also in preserving and maintaining the deposited shoots.

For the moment, all the shoots replanted are still attached after several storms, which is a sign that the attachment method is working. However, there is still a lot of follow-up work to be done to analyse their evolution and survival over time and to assess the suitability of the methodology used.

Neptune seagrass: a plant with a key ecological function

Neptune seagrass (Posidonia oceanica) plays a key ecological role as a fundamental habitat for many plant and animal species. It is decisive in many processes, such as mitigating the effects of climate change, capturing, and fixing carbon dioxide, and protecting the coast from the effects of storms. For these reasons, it is a protected species at European, national, and regional levels. However, it is in the process of generalised regression, caused by a combination of different anthropogenic impacts. Some of these impacts are the impoverishment of water quality, global warming, or the mechanical impact on the seabed, mainly caused by boat mooring and anchoring.