Ria Formosa
The Parque Natural da Ria Formosa is a nature reserve, which mainly consists of a lagoon on the southern Portuguese Algarve. The lagoon is a protected area of 170 km ², one of the largest lagunaren protected areas in Europe, where the actual lagoon covers 83.5 km ². She is about five natural and one from 1927 to 1952 created artificial sixth output connected to the open sea; the latter serves as a link from the Atlantic to the port of Faro, with its 42,000 inhabitants, situated on the northern edge of the lagoon. Two other towns lie at the edge of the lagoon, namely Tavira ( around 25,000 inhabitants) at the eastern edge of the lagoon and Olhão ( approximately 31,000 residents) between Faro and Tavira. The park stretches between Quinta do Lago in the West, which is 20 km west of Faro, up to Manta Rota, east of Tavira.
The lagoon landscape in its current form is caused by the earth and tsunami of 1755. The lagoon offshore island chain consists of the Ilha de Faro (correct: Peninsula de Ancão ), Ilha Deserta (also called Ilha Barreta ), Ilha da Culatra, Ilha da Armona, Ilha de Tavira, Ilha de Cabanas and Peninsula de cacela.
1978, of the 83.5 km ² total area of 48 km ² lagoon salt marshes, sand dunes and mudflats, 35.5 km ² channels, streams or other bodies of water, 0.9 km ² salt pans and 0.2 km ² tanks of aquaculture.
1975 waders were counted, and at 12,775 birds of 20 species have been recorded for the first time. 1976 and 1977 these figures were at 20.068 and 21.383. For them, the salt marshes are of great importance, as was demonstrated in 1984 and 1985. Place about a quarter to a third of wading birds remained in the area of salt pans on, although there were wide variations depending on the species to species that avoided the salt works, such as the bar-tailed godwit (Limosa lapponica ).
The 60- km long area was in 1987 placed under protection, on the one hand continue to allow fishing, on the other hand to obtain the resting place for migratory birds, but also a natural protection against the Atlantic Ocean. 1980-86 and 2001 to 2002, fish surveys were made, in each of which 57 species have been recorded. However, it turned out that the mullets were greatly reduced. It was concluded that the amount of organic material in the lagoon, less strongly dependent on the outflow of human intervention.
To the west of the lagoon have been analyzed how fast the volumes of the salt marshes in the face of rising sea levels increase, as the marshes grow vertically. The total volume was estimated at 1,549,215 m³. On average, one expects since then with vertical deposition rates of 0.4 mm per year between 1681 BC and 2001. Between 1941 and 2000, however, this rate increased to 8-9 mm per year.