The Aspretto naval base is located to the south of Ajaccio, the capital of southern Corsica. It covers an area of 42 acres and includes a sea port protected by a sea wall and a heliport. The sea wall covers an area of 4 acres and consists of 70% land and 30% marine environment. It has been a Natura 2000 site since 2007.
The naval base was opened in 1938. It was originally a base for seaplanes, and was subsequently used as a sea search and rescue centre. At present, the port housesboth militaryand pleasure boats, but the site is also home to severalpublic service departments (Customs, Departmental Land and Sea Division (DDTM), Coastguard and Sea Police, National Coastguard Rescue Service (SNSM) and French Navy).This ensures maximum coordination during operations. The Regional Operational Monitoring and Rescue Centres Corsica subdivision (sous-CROSS de Corse) is also housed at the base. It is responsible for monitoring maritime navigation throughout Corsica and handling communications.
The site is home to a colony of rare Audouin's Gulls (Larus audouinii), which is why it is a designated Natura 2000 site (ZPS FR9412001). This species is found almost exclusively in the Mediterranean and its IUCN conservation status is "Near Threatened". The military base is also home to other native, protected species such as the Ribbed Mediterranean Limpet (Patella ferruginea) and the Mediterranean House Gecko (Hemidactylus turcicus).
The Audouin's Gull
Corsica is the only place in France in which the Audouin's Gull nests. A colony has nested at the port sea wall at the Aspretto base in April each year since 1990, where it has bred and made a valuable contribution to the tranquillity of the site. The adult birds build their nests directly on the ground and raise between one and three chicks. The site is currently home to up to 60 breeding pairs, or 70% of the total population of this species in France.
The site is also an excellent place to observe and monitor the colony, which can be observed form a distance of 80 metres. The young birds are ringed, and returning adults are monitored remotely using binoculars, telescopes or high-quality cameras.
Until recently, the main threat to the colony was competition from the Yellow-legged Gull (Larus michahellis), its more precocious and corpulent cousin, who would evict the Audouin's Gulls from their nests and expose their eggs and chicks to predators. A series of authorised dissuasion, nest destruction and controlled culling operations were therefore performed on the Yellow-legged Gull population. These operations yielded excellent results, and this species has not nested at the site since 2011.
The Audouin's Gull is particularly vulnerable during the nesting period, and any disturbance, even temporary, can lead to lost chicks and breeding failures. One of the key aims of the conservation programme is therefore to manage human visitors to the site.
The sea wall also features a weak point close to one of the breeding areas, where a strong storm caused severe damage in 2009-2010.