Les marais endigués de la Ria Formosa (Algarve) face à un siècle de développement économique. Le cas de la réserve naturelle de Ludo

The lagoon of Ria Formosa, located on the southern coast of Portugal, contains large areas of marshes, which, as is the case of Ludo, west of the lagoon, had partially been reclaimed and drained at the end of the 19th century. The lack of information about such reclamation works in Portugal, the failure of the agricultural improvement of the Ludo marshes and the diversity of the wetlands formed after this complex history, makes it an interesting case study. Moreover, despite their status as natural reserve, these marshes are affected by increasing environmental damages and by growing economic pressures; it is presently surrounded by intensive farming zones, extending golf resorts and Faro's urban sprawling. Thus, using several methods and techniques (corings, D-GPS measures, salinity measures, use of historical archives, interview), we tried to determine the possible durability of this natural reserve and to evaluate the effective power of a natural park when confronted with powerful socio-economic forces.