Owing to its geographical position, its landscape diversity and limited human occupation, the Southwest Coast, an interfacial zone between the land and the sea, has developed its own specific features and a variety of habitats which are responsible for the wealth of its flora and fauna. It is one of the last and most important stretches of wild coastline in the South of Europe, with great extensions remaining almost unaltered by human activities and building, and benefiting from an extremely low demographic density, albeit with increasing anthropic pressure, which, for the time being, is limited in time and space.
Basically, the coastline is made up of sedimentary rock. The eological substrata are mainly of sandstone or sandy shales, with schist and limestone in certain zones, exhibiting interesting stratigraphical sequences exposed by marine erosion along the coast, and outcrops and formations which range from the Carboniferous to the Quaternary. From the geomorphologial viewpoint, the coastal cliffs exhibit extremely interesting features, displaying differing stages of erosion, profiles and types of evolution.
The PNSACV is an area with a great biodiversity of both species and natural habitats, many of which are peculiar to the area. Thirty-five of the natural habitats which are included in Directive 92/43/EEC (Habitats Directive) occur here. There are a wide range of habitats along the coastline, including marshes, cliffs, dune systems and lacustrine systems, including five priority habitats. Near the coast there is a coastal plateau, cut into by intermittent Mediterranean watercourses and small permanent streams, with the greatest concentration of temporary humid habitats in the country, several of which are conservation priorities.
On the escarped coastline between Sagres and SBo Vicente, in climatic conditions strongly marked by the Atlantic influence, there are a remarkable number of natural habitats, rich in endemic features, some of which are rare worldwide having attracted scientists from all over the world. The Council of Europe's Biogenetic Reserve, which has been in existence at Sagres since 1988, is symptomatic of the international recognition of its remarkable flora.
One of the most noteworthy groups is that of terrestrial vertebrates, with one of the highest numbers of reproducing species in Europe. There is a significant abundance of certain species; a presence of rare and or threatened species; and interesting cases of ecological adaptation in the case of others. The otter, Lutra lutra has an interesting marine population which frequents the estuarine and riverine environments along the rocky coast (one of the three colonies in Europe and the only one in Portugal). There is also a varied, nesting, bird population, in particular on the coastal cliffs, with the only cliff-nesting colony of the white stork, Ciconia ciconia, in the world. In addition to the species that reproduce in the region, there are also many migratory species in the PNSACV, due to the very particular abiotic factors and the low humanisation of the landscape. The importance of the area as a site for the study of bird migration has been recognised for decades by researchers at home and abroad. The autumn migration of gliding birds across Sagres -S. Vicente, which, amongst other species, involves several thousand birds of prey, is of special significance. Certain animals in the PNSACV are in imminent danger of extinction. This is the case of the Iberian lynx, Lynx pardinus, for example, for which extremely urgent conservation work is necessary. In spite of the few surveys carried out on invertebrates, several endemic species have been registered.
The Natural Park's marine ecosystem displays certain biophysical and ecological characteristics which are singular worldwide. The area proposed is a coastal zone, relatively unaffected by human intervention, with unique biophysical and ecological characteristics. It is a zone of confluence for three distinct masses of water; Mediterranean, Boreal Atlantic and Tropical Atlantic. The diversified nature of the sea bottom on the coastal strip, the existence of several geographical features such as islets, bays and capes and the occurrence of deep water upsurge phenomena in summer, all contribute to the presence of important marine resources and high levels of biodiversity. (Afonso, 1995; Canario et al. 1994; Cancela da Fonseca, 1986; Gonplves, 2000; Gonplves e Silva, 2000)
From the archaeological viewpoint, and seen as a whole, the area of the PNSACV possesses undeniable cultural interest associated to the role of the sea and its resources, and the subsistence of populations, particularly during periods of crisis. The macrolithic tools known as Mirense (from Mira); the Mesolithic and Neolithic shell deposits; the megalithic clusters of Vila do Bispo, the important Roman archaeological stations of Boca do Rio and Pessegueiro; the association of Sagres with Prince Henry the Navigator; the medieval sea trade; the different forts built to protect settlements against pirates; the Churches ... all this historical wealth enhances and adds to the exceptional natural heritage of the area (Quaresma. 1988). In particular, Sagres' monumentality made it a point of encounter for several civilisations, and a place of pilgrimage for the faithful of different beliefs, who have attributed a sacred and spiritual character to the site (Promontorium sacrum). It is also symbolically linked to the endeavours of the Portuguese Discoveries, especially through its association with Prince Henry the Navigator (who resided in the neighbouring zones of Lagos and Raposeira) and to the almost mythical character of his adventurous personality.
( Quaresma, 1988; Torres, 2002; Gomes, 2002; Mesquita, 2002; Coelho, 2002;JoBo. 2002)