PROJECT DESCRIPTION
BACKGROUND
Worldwide coastal areas are threatened by increasing erosion, flood risks, and habitat loss due to the impacts of climate change. These issues are more evident along non-rocky coasts, where erosion has increased due to the reduction of the sediment load from rivers, natural and anthropogenic subsidence phenomena, rising sea levels and a greater frequency of storms. In natural coastal marine ecosystems, some organisms can build natural biogenic reefs and other habitats which are able to provide coastal defences. Biogenic reefs are secondary marine substrates made by autogenic ecosystem engineers that provide habitats for various species. Ostrea edulis, Sabellaria alveolata and Sabellaria spinulosa are native marine ecosystem engineers, able to create three-dimensional reefs that retain sediment and dissipate wave energy, counteracting coastal erosion and creating ecological niches allowing biodiversity rich natural habitats to flourish.
These reefs provide several ecosystem goods and services such as biodiversity enhancement, improved water quality and clarity, increased fish and shellfish production, sediment stabilisation and wave energy dissipation. Native oysters have almost disappeared from European coasts over the course of the past few centuries mainly due to overexploitation, habitat degradation, disease and the introduction of non-native oyster species. Sabellaria spinulosa reefs are rare in the Mediterranean Sea, representing marginal habitats having lost most of their ecosystem functions at the regional level. Despite the ecological importance of these reefs and their decline, no protection measures are foreseen for the vast majority of them, even though the reefs are included in the European Red List of Habitats. The Bevano river estuary, located in the municipality of Ravenna in the Emilia-Romagna Region of Italy, boasts one of the rare stretches of coast in the region that is still not urbanized and devoid of intense tourist development. It is the only river mouth in the region free to evolve following the natural dynamics of coastal sedimentary systems. The area represents a natural oasis characterized by transitional ecotones between fresh, brackish, and marine waters and wooded, dune and beach systems. The space, which is Italian state-owned area, was entirely dedicated to nature conservation and designated as a NATURA 2000 protected area (IT4070009 “Ortazzo, Ortazzino, Foce del Torrente Bevano”, type C SPA+SCI+SAC). The area is threatened by coastal erosion, saline intrusion and flooding due to the lack of natural nourishment of the beaches, subsidence, rising sea levels and the mounting frequency and intensity of storm surges. In the past, the problem of coastal defence in the area had been tackled by artificial breakwater dams. However, these structures have an adverse effect on natural ecosystems by altering marine and coastal communities.
OBJECTIVES
LIFE NatuReef aims to apply the best practices available to the restoration of native oyster and sabellaria reefs, seeding the native species in the Bevano river mouth, a rare non-urbanized stretch of the northern Adriatic coast. The main objective is to create a reef of oysters and sabellaria worms, to nurture and restore rich biodiversity and to protect coastal habitats from sediment erosion and flooding caused by storm surges, and damage to coastal habitats due to salt intrusion. The restored reefs will enhance marine biodiversity, providing habitats and feeding grounds for priority and non-priority threatened species, such as sea turtles, seahorses, and seabirds. They will safeguard priority and non-priority habitats like sand dunes, coastal lagoons and pinewood from coastal erosion and salt intrusion, host endangered vegetation and serve as nurseries for priority bird species.
Project specific objectives are:
- Establish an oyster reef deployed on a rocky structural base building Base Limestone Reefs (BLS);
- Trigger the formation of at least three sabellaria reefs around the oyster reefs;
- Demonstrate the efficiency of biogenic reefs in enhancing marine biodiversity, protecting coastal habitats and maintaining fauna and flora;
- Increase public awareness of biogenic reefs restoration as a nature-based solution for coastal protection and marine biodiversity enhancement.
RESULTS
- Marine habitat restoration: establish an oyster reef of 4 000 m2 with a density of at least 10 ind. m2.
- Marine species richness: increase of at least 100 marine benthic species on the reefs, including algae, invertebrates, and fish.
- Coastal protection: wave-run up around 0.4 to 0.8 lower than expected in absence of structures during storms; volume of beach loss 0.15-0.45 lower than what was anticipated without protection.
- Coastal habitat and species conservation: halting the local decline of the coastal habitats to reduce the trend of the abundance of selected priority species.
- Public awareness: directly involve at least 200 people in BioBlitzes/Citizen Science and gain over 10 000 views on social media platforms.
