Combining oyster reef restoration and coastal protection in the Mediterranean Sea

The EU-co-funded LIFE NatuReef project aims to apply at a demonstration level the best practices available to restore native oyster and sabellariid reefs in a rare, non- urbanized, coastal stretch of the northern Adriatic coast: the Bevano river mouth (Ravenna municipality, Emilia-Romagna Region, Italy), which is a SAC and SPA under the EU Natura 2000 (IT4070009). For the first time in the Mediterranean Sea, the project has a dual aim: to restore these habitats and their biodiversity, and to provide a nature-based solution for protecting the coast from erosion, which is particularly intense here. In the region, native oysters in shallow waters have been almost disappeared for centuries, and sabellariid reefs are rare and fragmented, representing marginal habitats that have lost most of their ecosystem functions. Besides the well-known ecosystem goods and services, as well as the social and economic benefits they may provide, both species are able to create three-dimensional reefs that retain sediments and dissipate wave energy, counteracting coastal erosion. As living structures, they have the potential to grow and adapt and, to some extent, counteract some of the effects of climate change, such as sea level rise and increased storm and flooding event frequency and intensity, thereby contributing to the resistance and resilience of the coastal marine ecosystem. To achieve these multiple objectives, it was necessary to design a wide and intricate limestone substrate with iron cages appropriately sized and positioned according to the hydrodynamic, geomorphological, and sedimentary conditions, using numerical models based on precise surveys. The adults of Ostrea edulis used for restocking came from offshore natural banks. To repopulate Sabellaria spinulosa, aggregation nuclei originating from populations developing at the basis of nearby traditional breakwater reefs were transplanted. The effectiveness of the repopulation and the expected effects on the surrounding habitats and protected species are being monitored.