REPIC

REPIC : AN EXPERIMENTAL PROGRAM FOR THE RESTORATION OF POSIDONIA MEADOWS !

The REPIC programme (« REstaurer la Posidonie Impactée par les anCres », Restore posidonia impacted by anchors) was initiated in 2019 by Andromède Océanologie in partnership with the Rhône Méditerranée Corse Water Agency and NAOS. It allows the replanting of posidonia meadow fragments on workshop sites particularly impacted by anchoring and, thus, to initiate a restoration dynamic (reinforcement of populations) of these meadows. REPIC uses a sampling technique that has no impact on the seagrass beds: the planting of floating bundles torn off by anchors during the summer season (or broken off naturally). These fragments have the following advantages: high availability, moderate collection effort, no impact on existing populations. These fragments are transplanted into areas of dead matte using biodegradable staples specially designed for the project.

Transplanting is done by hand on predefined areas after the fragments have been surrounded by a biodegradable staple.

Since the program was set up three years ago, two restoration sites (Golfe Juan and Rade de Beaulieu sur Mer, between 1.5 and 30 meters deep) have been defined. Due to the former degradations suffered by the Posidonia meadow and the new protection measures put in place (especially anchoring regulations), these geographical sites of the REPIC program are now suitable areas to test new methods of restoration of these meadows.

Each year, scientific monitoring is carried out on the restored areas: individual monitoring of fragments in permanent quadrats, visual monitoring of all the restored areas by photogrammetry, monitoring of the carbohydrate reserves of the fragments and monitoring of the evolution of the temperature of the area. The geographical site effect is also tested by analyzing different environmental conditions at each site (salinity, currentology, surface temperature and surface concentration of chlorophyll a).

The areas are gridded and made up of circles of different densities. @Andromède Océanologie

Thanks to the various campaigns carried out between 2019 and 2023 (108 days of fieldwork, 730 hours of diving), the total restoration area has reached 2,000 m², with over 140,000 beams transplanted. The success rate of the REPIC operation is now estimated at over 80%. Scientific monitoring data are processed and made available on the MEDTRIX online mapping platform for monitoring Mediterranean coastal waters and ecosystems (http://plateforme.medtrix) as part of the RESTAU-MED project, which presents ecological restoration projects. For more information on this network, please visit the RESTAU-MED project page.