Serras de Aire e Candeeiros Natural Park

The park is located in the central region of Portugal marking the border between the provinces of Beira Litoral, Ribatejo and Estremadura. It comprises part of the municipalities of Rio Maior, Alcobaça, Porto de Mós, Batalha, Leiria, Ourém, Torres Novas and Alcanena.[3]

This area was made a protected area in 1979 with the intend to protect the existing natural aspects and architectonic heritage.

PNSAC is mainly composed by mountain ranges (Serra) and plateaus: Serra de Aire in the northeast, Serra de Candeeiros in the west, adjacent to Aire, between Porto de Mós and Rio Maior, the Santo António plateau in the centre and part of the São Mamede plateau in the north, and Serra de Santo António, perpendicular to both Aire and Candeeiros.[1]

Fórnea waterfall

Polje of Minde-Mira de Aire floods with water in the winter months

Due to the extreme permeability of the limestones, the park is absent of shallow watercourses, instead, it has 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 rivers.[1] Another striking characteristic of the landscape is the consequent dryness, to which faults, escarpments and rocky outcrops give the park a vigorous and harsh trace.[2]

This nature park is evidenced by the relief, as a prominent mass that rises about 200 m (660 ft) relative to its surroundings and for its geological constitution of highly permeable limestone targets, to which results its great dryness. And water, which is practically invisible on the surface, the main erosive agent, modeler of this unusual morphology. The character of these landscapes is also associated with presence of countless stone walls, depressions (poljes) with a varied agricultural use and the olive groves on stony and difficult to work slopes, for which pits are opened and terraces or stone walls are built to hold the scarce existing soil.[2]

The relatively abundant rains quickly disappear through the cracks in the stripped rocks where installs a Mediterranean vegetation of Quercus coccifera, Pistacia lentiscus, wild olive and aromatic herbs.[2]

In the low areas or in the depressions where water is collected and accumulates from infiltration at the higher surfaces, there are processes that have similarities with the river dynamics that enriches the flood beds with sediments - after the accumulation period, of water in the poldjes, the depressions are emptied which gives rise to a fertile terra rossa plain where maize, potatoes, vines are grown, a variety of other crops and even vegetable gardens, resulting in a mosaic of colors and textures with great seasonal dynamics.[2]

The karst landscape still has a high aesthetic value due to the fact that erosive phenomena, both superficial as well as underground, gives rise to expressive and unexpected “natural sculptures”.[2]

The settlement is originally concentrated on the periphery of the limestone massifs and is largely determined by availability of water. Currently, with the population less dependent on agricultural and pastoral activities, there has been a dispersion of buildings in the landscape, both for housing and for support of other economic activities. This diversification of the economy is partly responsible for the abandonment of the most traditional activities.[2]

Santo António Caves

The park is located in the Estremenho Limestone Massif where complete sedimentary series of several Jurassic floors and tectonic accidents that testify not only to the distensive phases of opening the Lusitanian Basin during the Mesozoic, but also the alpine compressive regimes that were installed from the end of the Cretaceous. Among the testimonies of high scientific value in the park, the paleontological heritage, with an exceptional set of dinosaur ichnofossils, stands out. Also the occurrence of geological cuts and the unique exposure of representative lithostratigraphic sequences in the evolution of depositional environments and the occurrence of some imposing fault cliffs. However, it is with regard to the elements of nature that the PNSAC stands out the most, being considered as the most important karst region in Portugal. The scarce runoff from the waters gives rise to an extensive and complex underground drainage system which results in a unique speleological heritage, represented by countless algars and caves.[4]

Typical Mediterranean vegetation of the park, overlooking the Ribatejo plains

Moss is commonly seen on limestone and open woody areas of the park, along with Himantoglossum robertianum and Cistus albidus, seen on the picture

The natural park hosts more than 600 different plant species,[5] most are Mediterranean while others are Atlantic, the typical cover includes: Quercus coccifera, Quercus rotundifolia,Quercus faginea, Quercus suber, Phillyrea latifolia, Rhamnus alaternus, Pistacia lentiscus, Olea oleaster, Olea europaea, Lavandula stoechas, rosemary, oregano, Hedera hibernica, Erica arborea, bay laurel, Arbutus unedo and the occasional maritime pine and stone pine forests.[6]

It has 27 different species of orchid, about 50% of all the species native to Portugal.[1]

It also provides habitat for various flora that is uncommonly found in Portugal including: Iris subbiflora, Paeonia broteri, Paeonia officinalis, Jonopsidium abulense, Orobanche latisquama, Scrophularia sambucifolia, Antirrhinum linkianum Teucrium chamaedrys, Salvia viridis, Inula montana, Aristolochia pistolochia, Teucrium fruticans, Ophrys fusca, 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, Arenaria grandiflora, which is currently only known to exist in the park.[6]

Although lacking any water courses, the park has a surprising amount of amphibians, 13 species are known, which include the marbled newt, the Iberian ribbed newt, the western spadefoot, the common midwife toad, the Iberian painted frog, the Mediterranean tree frog, the Iberian frog, the Perez's frog, among others.[1][7]

Reptiles include the spiny-footed lizard, the horseshoe whip snake, the Carbonell's wall lizard, the Iberian wall lizard, the Spanish psammodromus, the ocellated lizard, and the Lataste's viper.[1]

Bats represent almost half of the mammal species in the park, with 21 known different species.[1][7]

Despite the great annual precipitation, the park has a large water deficiency in the summer due to the porous nature of its soil, as seen in Serra de Santo António

The park has a Mediterranean climate, with mild, rainy winters and warm to hot, dry summers but variations in temperature, precipitation and insolation occur. Areas closer to the Atlantic have warm summers (with average summer highs around 24 °C (75 °F)) whilst areas that border the Ribatejo tend to have hot summers (with average summer highs around 28–29 °C (82–84 °F). Altitude also plays a role, at altitudes above 400 m (1,300 ft), precipitation is plenty, with values above 1,200 mm (47 in) per year, but can go down to 800 mm (31 in) at lower altitudes.[1] Average temperature ranges from 13.5 °C (56.3 °F) at the top of Serra de Aire, to 16.0 °C (60.8 °F) at the lower plains.[8][9]

Fog is very common in winter, and in the summer, morning fog is also usual. 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.[8][9] In general, Serra dos Candeeiros has a more Atlantic influenced climate, whereas Serra de Aire has a more Mediterranean influenced climate.

The park contains two Middle Jurassic tracksites, the sauropod footprints of Serra de Aire and the dinosaur footprints of Vale de Meios, both are the oldest known dinosaur footprints in the Iberian Peninsula.[11] The Serra de Aire tracksite is one of the few sites in the world where Middle Jurassic sauropod dinosaur tracks can be found.[12] The Cave of Aroeira near the park has the earliest recorded human trace in Portugal, along with deer, equids, rhinoceros, bear, a large bovid, a caprid, and a Testudo tortoise. The Jurassic Beach of São Bento, discovered in 2003, has a variety of fossilized echinoderms.[13] Squeletal remains of Pleistocene brown bears have also been discovered in Algar do Vale da Pena, near the village of Moita do Poço.[14] There are also Roman remains, notably a road in Alqueidão da Serra, Porto de Mós which dates between the centuries I AD and I BC.[15]

• 
  Theropod footprint in Vale de Meios
• 
  Sea urchin
• 
  Crinoid
• 
  Sauropod footprints of the Serra de Aire Natural Monument
• 
  Roman road of Alqueidão da Serra
• 
  Fórnea

Wind turbines and quarries are the main threat to PNSAC's ecosystem

Even though a protected nature area was created to protect the existing natural aspects and architectonic heritage, the construction of quarries and wind turbines have increased since then, placing many of the local fauna and flora at risk. Every year, dozens of birds and bats are killed by the blades of wind turbines and severe numbers of reptile and amphibian species are roadkilled.[1] Some measurements taken to prevent this include the investment in nature tourism, scientific investigation and agriculture, particularly biological farming.[16]

• 
  East side of Serra de Aire as seen from the castle of Torres Novas
• 
  West side of Serra de Aire as seen from Fátima
• 
  Southeast view of Serra de Santo António from Alcanena
• 
  West side view of Serra de Candeeiros from Alcobaça