The Aire and Candeeiros Ranges Natural Park (in Portuguese, Parque Natural das Serras de Aire e Candeeiros, or PNSAC) is a natural park in the Central-West region of Portugal. It occupies an area of and is the most important limestone deposit in Portugal, with a variety of geological formations and climate associated with karst geomorphology and topography, such as underground caves and sinkholes. It was designated a protected area in 1979 with the intent to preserve its natural aspects, and the architectonic and cultural heritage linked to the local human populations.
Location The park is located in the Central-West region of Portugal defining the border between the Estremadura and Ribatejo provinces, and the Leiria and Santarém districts. It comprises part of the municipalities of Alcanena, Alcobaça, Batalha, Leiria, Ourém, Porto de Mós, Rio Maior, Santarém and Torres Novas.
Natural Heritage Geology With a mountainous landscape, PNSAC contains some of the most interesting geomorphological features within Portugal. It mostly includes mountain ranges, locally designated as "Serras", and plateaus.
Orogeny The park is located within the Estremadura Limestone Massif, a geological unit deposited during the extensional rifting phases of the Lusitanian Basin during the Mesozoic era, and subsequently structurally deformed by the alpine compressive phases established from the end of the Cretaceous period onwards. The São Mamede Plateau and the Aire Range are the erosional remnants of a rollover anticline created and exposed by those tectonic processes.
Geomorphology The Jurassic period rocks of the limestone massif flourish to a great extent, standing out by its relief as a prominent mass that rises about relative to its surroundings.
The main topographical features in the park are: Aire Range () in the northeast The adjacent Candeeiros Range () to the west, between Porto de Mós and Rio Maior Santo António Plateau in the centre Part of the São Mamede Plateau to the north.
The park's white and jointed limestone strata are constantly dissolved by the relatively abundant rainwater, which preferentially flows along and infiltrates through the joints, and further widens the natural fissures that so form in the process, on the surface and deep below the ground. In such ways, water, practically invisible on the surface, is the main erosive agent, forming karst features. After infiltrating and flowing from higher ground, and on surface depressions where the rainwater outflow cannot match the inflow (such as poljes), water is naturally and ephemerally pooled, and sediment is deposited. After the wet season, these depressions eventually drain, leaving behind newly deposited fertile terra rossa. These phenomena justify the absence of shallow watercourses, and the presence, instead, of a vast network of underground galleries, being perhaps one of the largest freshwater reservoirs in the country, giving rise to some important water courses, such as the Alviela and Lena river springs.
Karst Features The park includes a great diversity of karst features, such as underground caves, pit caves, sinkholes, uvalas, poljes, limestone pavements, and ponors, among others. There are over 130 identified caves in the park. Some notable cave complexes include the Mira de Aire Caves, the Alvados Caves, the Almonda spring caves (including the Cave of Aroeira) and the Algar do Pena.
Other notable geological formations include: Minde-Mira de Aire Polje, a great karst depression and Ramsar wetland located between the towns of Minde and Mira de Aire, which floods with some frequency during the winter. Alviela karst spring and the Ribeira dos Amiais ponor Fórnea, a natural amphitheatre formed by temporary springs Arrimal Lagoons, sinkholes with naturally waterproofed bottoms with clays and other sediments The Salinas de Rio Maior, the only extant inland salt pans in the Iberian Peninsula, centered on a brine well.
Paleontology The park contains some small and scattered Middle Jurassic dinosaur tracks locations that dot the landscape, but two major dinosaur trackway sites are outstanding. Both sites are the oldest known dinosaur footprint locations in the Iberian Peninsula.:
Aire Range Dinosaur Tracks Natural Monument, one of few sites in the world where Middle Jurassic sauropod dinosaur tracks can be found. It consists of many unusually well-preserved prints, including claw and digit impressions. Vale de Meios dinosaur tracksite, where over 1000 individual footprints forming numerous trackways are observable.
Also notable are the following paleontological locations: The Vale Florido biostromes consisting of fossilized coral and algae. The Barranco de Zambujal finds, including Ammonites, belemnites, brachiopods, bivalves and ichnofossils. The São Bento Jurassic Beach site, discovered in 2003, has a variety of fossilized echinoderms.
Skeletal remains of Pleistocene brown bears have also been discovered in Algar do Vale da Pena, near the village of Moita do Poço.
Climate
The park has a Mediterranean climate, with mild, rainy winters and cool to hot, dry summers but variations in temperature, precipitation and insolation occur throughout the region. Areas closer to the Atlantic in the west have warm summers (with average summer highs around ) whilst areas that border the Ribatejo to the east tend to have hot summers (with average summer highs around . Altitude also plays a role. At altitudes above , precipitation is plenty, with values above per year, but can go down to at lower altitudes. Average temperature ranges from atop the Aire Range, to at the lower plains.
The prevailing N-NW winds carry air masses loaded with moisture that cause intense fog and strong winter rainfall. As summer approaches, the Azores High moves further north. Clear skies become more frequent and rain is scarce between July and August. Fog is very common in winter, and in the summer, fog created by the marine layer can move from the Atlantic to the interior, but usually evaporates by midday. Average relative humidity is very high in the winter and values in the summer can have extreme variations, often below 40% during the day and above 80% at night. Temperatures at night are generally cool year-round but the high humidity along an absence of wind can make it more pleasant. Insolation varies between 2300 hours in the northwest mountains (south of Porto de Mós) and 2650 hours in the east. In general, Candeeiros Range receives a larger influence from the Atlantic, whereas the Aire Range has a more Mediterranean influenced climate.
Ecology Flora
The natural park is part of the Southwest Iberian Mediterranean sclerophyllous and mixed forests and hosts more than 600 different plant species. The vegetation that characterizes the PNSAC is the result of the bioclimatic influences on the territory. There is a great wealth of species with a diversity of sizes and origin (from Atlantic Europe, the Mediterranean, the Iberian Peninsula and North Africa), rare and unique Portuguese species, paleoclimatic species, some even used for medicinal, culinary, aromatic or ornamental purposes. Though floristically rich, the park has suffered dramatic changes over the years. The Alvados Depression is a clear example of this dynamism; at present its landscape is agrarian; however, centuries ago, at the time of its occupation by its first settlers, the area was a marsh that was surrounded by oak groves, pine groves and strawberry trees. Later, with the romanization, it became an olive grove with grafts of wild-olive.
The park has five main associated landscapes:
The shrublands, with typical Mediterranean scrub which include Quercus coccifera, Erica arborea, Erica scoparia, Ulex, Cystus, Phillyrea latifolia, Phillyrea angustifolia, Rhamnus alaternus, Pistacia lentiscus, Olea oleaster, Lavandula stoechas, rosemary, oregano, bay laurel, Arbutus unedo, Daphne gnidium, Lonicera etrusca, Crataegus monogyna, Rubia peregrina, Smilax aspera, Rubus ulmifolius The humid oak and pine forests, featuring Q. rotundifolia, Q. faginea and Q. suber, Pinus pinaster, Pinus pinea, Hedera hibernica, Viburnum tinus, Ruscus aculeatus, Pteridium aquilinum, one of the most representative vegetative formations in the park. Q. pyrenaica is restricted to the centre of the park and Q. suber is uncommon due to its dislike for calcareous soils
The lithophyte plants, such as Sedum forsterianum, Petrosedum sediforme, Sedum album, Coronilla glauca, Thymus zygis, Arabis sadina, Rhamnus alaternus, Antirrhinum linkianum, Polypodium cambricum, Asplenium trichomanes, Asplenium ruta-muraria, Asplenium ceterach The human-introduced eucalyptus forests, olive groves and pastures, which are commonly associated with grasses such as Koeleria vallesiana, Dactylis glomerata, Melica minuta, Briza maxima, Hordeum murinum, Brachypodium phoenicoides, Bromus diandrus, Holcus lanatus, Lagurus ovatus, Helictochloa marginata, Euphorbia paniculata, Euphorbia characias, Convolvulus arvensis The riparian forests of Ulmus minor, Sambucus nigra, Salix atrocinerea, Salix alba, Alnus glutinosa, Tamarix gallica, Fraxinus angustifolia, very rare and degraded
Additionally, the park has 27 different species of orchid, about 50% of all the species native to Portugal and provides habitat for various calcerous flora that is uncommonly found in Portugal including: Iris subbiflora, Paeonia broteri, Paeonia officinalis, Jonopsidium abulense, Himantoglossum robertianum, Orobanche latisquama, Petrosedum sediforme, Scrophularia sambucifolia, Antirrhinum linkianum Teucrium chamaedrys, Salvia viridis, Inula montana, Aristolochia pistolochia, Teucrium fruticans, Ophrys fusca, Phlomis lychnitis, Fritillaria lusitanica and some Portuguese endemics such as Silene longicilia, Arabis sadina, Arrhenatherum pallens, Ulex jussiaei, Narcissus calcicola, Ulex airensis., Saxifraga cintrana and a newly described species in Portugal, Arenaria grandiflora, which is currently only known to exist in the park.
Fauna
The distribution and biodiversity of mammals is in part due to bioclimatic and geoecological characteristics. The fauna was drastically affected by the human occupation of this territory, which devastated habitats and destroyed resources. According to Alho (1997), a total of 204 species of vertebrates, of which 136 are birds, have been identified. Mammals located in the park can be divided according to size into micromammals, mesomammals and large mammals. Bats represent almost half of the mammal species in the park, with 21 known different species.
The micromammals, present by the orders insectivores, chiropterans, and rodents include the European hedgehog, the greater white-toothed shrew, the Etruscan shrew, the Iberian shrew, and the Spanish mole, the house mouse, the Algerian mouse, the black rat, the wood mouse, the Lusitanian pine vole, the Mediterranean pine vole, the greater horseshoe bat, the Mehely's horseshoe bat, the lesser horseshoe bat, the Mediterranean horseshoe bat, the Geoffroy's bat, the Bechstein's bat, the greater mouse-eared bat, the Natterer's bat, the lesser mouse-eared bat, the common pipistrelle, the serotine bat, the common bent-wing bat, or the European free-tailed bat The mesomammals are present by species of the order lagomorpha, which include the European rabbit and the Granada hare the large mammals group the carnivore and ungulate orders and are represented by the European badger, the beech marten, the Eurasian otter, the least weasel, the European polecat, the red fox, the common genet, the Egyptian mongoose, the Iberian lynx, the European wildcat and the domestic donkey