The Vale do Guadiana Special Protection Area has an area of 76.547 hectares and it is superposed to the Vale do Guadiana Natural Park (93%) and to the Guadiana pSCI (proposed site of Community Interest) (23%). The SPA comprehends territory from 4 municipalities: Alcoutim (1%), Beja (5%), Mértola (82%) and Serpa (8%).
The landscape of this SPA is characterized by plains where the quartzite formations of the S. Barão and Alcaria mountain ridges stand out along with the steep valleys of the Guadiana River and of its affluents. This SPA is characterized by extensive cereal farming areas, scrub forests, holm oak groves and forest areas as well as by the valleys of the hydrographic basin of the Guadiana River.
In the valleys and small rivers some characteristic species of plants occur, such as the Oleander (Nerium oleander), the African Tamarisk (Tamarix africana) and the “Tamujo” (Securinega tinctoria). In this area we can also find endangered plant species, such as the Clover Fern (Marsilea batardae), that grows near small rivers, and the Thyme (Thymus camphoratus) which is an endemic specie (ICN 2001). Regarding the fish population, there are nine endemic species of freshwater fish and three species that occur only in the hydrographic basin of the Guadiana River, the ”Saramugo” (Anaecypris hispanica), the Guadiana Ray-Finned Fish (Chondrostoma willkommii) and the Smallhead Barbel (Barbus microcephalus). In this area we can also find 13 species of amphibians and 20 species of reptiles. As for mammals, the European Otter (Lutra lutra) has a regular presenceon watercourses and there are several occurrence records of the Wildcat (Felis silvestris) (ICN 2001).
The Vale do Guadiana SPA is extremely important for rupicolous birds that nest on the cliffs along the valley of the Guadiana River, such as the Bonelli’s Eagle (Aquila fasciata), the Black Stork (Ciconia nigra), the Golden Eagle (Aquila chrysaetus) and the Eagle owl (Bubo bubo). It is also important for steppe birds, especially for the Lesser Kestrel (Falco naumanni), that occurs in an important colony in the town of Mértola, which is the only urban colony in Portugal. The Vale do Guadiana SPA holds one of the most significant populations of Black-bellied sandgrouse (Pterocles orientalis), and three important breeding areas for the Great Bustard (Otis tarda) (ICNB 2006).