Stagno di San Giovanni: Geographic Atlas and Protected Coastal Wetland Landscape of Sardegna

Stagno di San Giovanni already in the 1970s was placed on the list of internationally important wetlands developed under the Ramsar Convention, marking it as one of the early Italian sites recognized for its significance to waterbirds and wetland ecology. With the later adoption of the European Union Birds Directive, the lagoon was classified as a Special Protection Area, extending its international profile into the formal EU conservation framework and grouping it with neighboring brackish waters under a single ZPS designation.

Alongside this ecological recognition, the lagoon has long been treated as a productive fishery. It belongs to the demesne of the Region of Sardinia, which grants professional exploitation rights for its fish resources, an arrangement that reflects both the cultural importance of lagoon fishing in Sardinia and the administrative tradition of treating such wetlands as shared regional assets rather than purely protected zones.

Stagno di San Giovanni lies in the low coastal plain that runs along western Sardinia, between Oristano and the southern part of the coast. The surrounding terrain is characterized by flat-to-gently-undulating terrain, sandy soils, and dune cordons built up by longshore marine processes. Inland, the lagoon is bordered by agricultural lowlands and Mediterranean scrub vegetation typical of the Sardinian coast.

The waters of the lagoon itself are brackish rather than fully saline, shaped by the inflow of the Rio Mogoro and Rio Sitzerri, which deliver freshwater from the inland catchment. The combination of shallow brackish water, exposed muddy and sandy margins, and adjacent coastal flats defines the visual character of the site, where wide horizons of still water, exposed sediments, and reed-edged shores dominate the view.

As a Ramsar-listed coastal lagoon, Stagno di San Giovanni represents a classic Mediterranean brackish-water habitat, where freshwater inflows mix with seawater to produce salinity conditions intermediate between a true lagoon and a coastal pond. The site forms part of an interconnected group of similar wetlands along the southwestern Sardinian coast, which collectively provide habitat for waterbirds, shorebirds, and a range of estuarine and lagoon-dependent species.

The ecological value of the site rests on the mosaic of shallow water, exposed mudflats, fringing reedbeds, and adjacent salt- and freshwater transitions that characterize these Sardinian coastal systems. Such habitats support seasonal cycles of migratory and resident birdlife, while the brackish conditions sustain fish and invertebrate communities that have long supported traditional lagoon fisheries. The lagoon therefore functions simultaneously as a refuge for wildlife and as a productive natural system.

The lagoon's designation under the EU Birds Directive reflects its role as habitat for a community of waterbirds and shorebirds typical of Mediterranean brackish environments. Although detailed species inventories are not the focus of the source documentation, the site's inclusion in a network of protected wetlands covering Stagni di Santa Maria, Pauli Biancu Turri, and the Marceddì and Corru S'Ittiri lagoons indicates that the area is recognized for hosting populations of migratory and wintering birds that rely on this chain of coastal wetlands.

The presence of commercial species within the lagoon, including sea bream, mullet, sea bass, eel, crab, sole, clams, and arselle, also highlights the broader estuarine and lagoon fauna of the site. These species are characteristic of the brackish-water ecology of Sardinian coastal ponds and form an important part of the lagoon's overall biodiversity.

Stagno di San Giovanni has been recognized at international level as a wetland of importance since the 1970s through its Ramsar listing, which marked it as part of the global network of sites considered significant for waterbirds and wetland ecosystems. Its later designation as a Special Protection Area under the EU Birds Directive expanded its conservation framework, embedding the site in the European Union's wider strategy for the protection of wild birds and their habitats.

The broader protected area that the lagoon belongs to is not an isolated designation. The ITB034004 zone links Stagno di San Giovanni with Stagni di Santa Maria, Pauli Biancu Turri, and the Marceddì and Corru S'Ittiri lagoons, reinforcing the ecological connectivity between these wetlands and underlining their combined importance for migratory species. The conservation framework also explicitly intersects with the lagoon's productive use, recognizing that regional fishing rights and wetland protection operate alongside one another as part of the long-term management of the site.

The cultural identity of Stagno di San Giovanni is closely linked to the artisanal fishing traditions of southwestern Sardinia. The lagoon belongs to the regional demesne and is professionally fished for species such as sea bream, mullet, sea bass, eel, crab, sole, clams, and arselle, a small venerid shellfish characteristic of Sardinian lagoon fisheries. This fishing activity reflects a centuries-long local relationship with the brackish coastal wetlands of the island.

The shared municipal territory of Arbus and Terralba further embeds the lagoon in the everyday landscape and identity of local communities, where the stagno functions both as a natural area and as a working resource. The coexistence of Ramsar-level recognition and regional fishing rights is itself a notable cultural fact, illustrating how Sardinian lagoon management integrates cultural and ecological values within the same tradition.

Stagno di San Giovanni's strongest distinguishing features are its long-standing Ramsar status, dating from the 1970s, and its inclusion in the shared Special Protection Area ITB034004 that links it to the Stagni di Santa Maria, Pauli Biancu Turri, and the lagoons of Marceddì and Corru S'Ittiri. Its brackish, river-fed character, sustained by the Rio Mogoro and Rio Sitzerri, sets it apart from marine-only inlets and gives it the properties of a true Mediterranean coastal lagoon.

As a Mediterranean coastal lagoon in southwestern Sardinia, Stagno di San Giovanni sits within a region characterized by mild winters and hot, dry summers. Cooler months, when migratory and wintering waterbirds are most likely to be present on the wetland, are widely regarded as the most rewarding period for observing lagoon birdlife, reflecting the broader seasonal pattern of Mediterranean coastal wetlands. Summer brings higher temperatures and low water levels, conditions under which the site reads more strongly as a working fishing landscape than a wildlife-rich environment.