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The Berlengas are a Portuguese archipelago consisting of small Atlantic islands off the coast of Peniche, Portugal, in the Oeste Subregion region. These islands were traditionally known to British mariners as "the Burlings". The only inhabited island is its largest island, Berlenga Grande, although there is currently no permanent habitation in the archipelago. The other islands are grouped into two groups of islets, the Estelas Islets and the Farilhões-Forcados Islets.
The islands are thought to be a former sacred place adopted by the in the first millennium BC where the cult of Baal–Melqart was celebrated.
In 1513, with the support of Queen Eleanor of Viseu, monks from the Order of São Jerónimo established a settlement on the island to offer assistance to navigation and victims of frequent shipwrecks. The monastery founded there, the Monastery of the Misericórdia da Berlenga, remained until the 16th century, when disease, lack of supplies and poor communication (due to constant inclement weather) forced the monks to abandon their service on the island.
After the Portuguese Restoration War, during the reign of King John IV, the council of war determined that the demolition of the monastery ruins and the use of their rocks to build a coastal defense would help protect the coastal settlements; the Fort of São João Baptista das Berlengas was constructed from the remnants of the monastery ruins. By 1655, it had already, during its construction, resisted an assault by three Barbary Coast pirates.
The island's lighthouse (dubbed Duke of Braganza by locals) was constructed in 1841. In the 20th century a solar panel was installed in the lighthouse's column, providing a field of vision.
The International Coordinating Council of UNESCO's Man and the Biosphere Programme (MAB), meeting in Dresden (Germany) from 28 June to 1 July, while adding 18 new sites, included the Berlengas to the World Network of Biosphere Reserves (WNBR): in a statement on 30 June 2011, the list of classified reserves were presented.
There is little soil on the rocky archipelago, so little plant life is supported. Sea birds and marine life, such as mackerel, mullet, and swordfish are abundant.
The Fort of São João Baptista (English: "Fort of St. John the Baptist") is located in the waters off the southeastern coast of Berlenga Grande, on a small islet connected to the island by a causeway/arch-bridge and anchorage to the north. It has been retrofitted as a rest house for tourists to stay at while visiting the islands.
Granites of the Berlengas]] These islands consist of a pink granite very rare in Europe and very common in America, rich in . Erosion has created remarkable landforms, such as the "sugar loaf", or even narrow valleys with almost vertical walls (the carreiros, formed by selective erosion along subvertical fault planes), as well as numerous caves and marine tunnels
Magmatic mica schist
The different groups of islands have different morphology, composition and origins. Berlenga Grande and Estelas are of igneous origin, composed of , and occur in outcrops with rounded morphologies, generally with flattened tops. The Farilhões Forcadas group, on the other hand, consists of metamorphic rocks, where reliefs characterized by sharp peaks and vertical cliffs stand out.
Berlenga Island is a pink granite plateau with rounded shapes, marked by a very jagged coastline, where several coves, caves, arches, paths, small islets and rocks stand out. All these landforms were shaped by the continuous action of erosive processes over a long period of time. The very embedded and relatively aligned paths of Cações and Mosteiro stand out, which almost separate the island of Berlenga into two fragments, the Ilha Velha and the Berlenga itself, and give it a curious figure-eight shape.
It is hypothesized that the archipelago had its origin on a horst. Its absence on the Mesozoic suggests that, during this time, the Berlengas block was essentially subjected to erosive processes. The pink granite fragments and metamorphic rocks found at Cabo Carvoeiro or Baleal, as well as in the Papoa tuff breccia, similar to those recognized in the archipelago, confirms this hypothesis. It is also expected that this block was larger and had a different configuration than it currently has.
The absence of morphological structures typical of the erosion of granitic massifs and soils on the surface of Berlenga Grande suggest that it was underwater for long periods of time. Its rounded shape and the relatively flat surface of its top propounds the presence of an ancient marine abrasion platform, confirmed by the presence of numerous erosive forms, such as potholes, which developed on top of the applanation surface when it was at the bottom of the sea.
On the other hand, the existence of small cavities and caves in the cliffs above the current mean sea level, such as Furado Seco, and marine terraces that correspond to residual deposits of old beaches, located at similar altitudes, seem to indicate that sea level was once positioned on that horizon. These observations suggest significant variations in the mean sea level, possibly as a result of quaternary glaciations.
Additionally, Berlenga Grande has a poorly developed drainage network, (when precipitation occurs, rainwater is taken and falls directly into the sea in cascades), which clearly evidences that the erosion rate of the granitic massif is lower than the speed of variations in the mean sea level.
The older metamorphic rocks that outcrop in Farilhões and Forcadas are erosion-resistance peaks of an underwater mountain that widens considerably below sea level. These rocks are strongly deformed and contain textures and minerals characteristic of high pressure and high temperature environments, typical of the lower crust.
The climate of the archipelago is strongly influenced by the winds, very strong on the north-facing cliffs and more moderate on the southern coasts. These wind currents affect the distribution of flora and fauna in the islands. This climatic feature endows the archipelago with a unique ecosystem, both on land and at sea level.
The presence close to the mainland, whose coast is oriented north–south, also strongly influences the climatic characteristics of the island, especially in summer. In this season, the differential warming of the sea and the land causes the formation of a sea breeze during the day. This breeze strengthens the main wind current associated with the Azores High and gives rise to a wind regime known as the Nortada. These winds push surface waters offshore, causing cold waters from deeper layers of the water to replace warm surface waters in an upwelling process. This phenomenon causes frequent mists during summer and results in nutrient enrichment of surface water.
Average monthly temperatures in summer are cool (below ) and highs rarely exceed . In winter, the monthly averages remain high (above ) and the minimum above . The thermal amplitude (both diurnal temperature variation and yearly temperature variation) therefore remains moderate.
Due to generally cloudy conditions in the winter and the summer morning fog, the archipelago has a relatively low number of sunshine hours, though clear sky afternoons are frequent in the summer.
Averages for the closest point on the mainland to the islands, Cabo Carvoeiro, are expressed in the climate box below:
| +Average wind speed (km/h) | |||||||||||||
| Cabo Carvoeiro | 19.6 | 19.7 | 19.2 | 19.0 | 18.1 | 16.9 | 17.3 | 16.3 | 15.2 | 16.8 | 18.4 | 20.0 | 18.0 |
There are around 100 different plant species present on the archipelago.
Human presence led to the introduction of exotic species, like the ice plant and small mammals like the European rabbit and the black rat who work to diminish the native population.
The Berlengas archipelago is an important breeding area for seabirds such as the lesser black-backed gull and the yellow-legged gull, whose population increased dramatically due to artificial feeding and has become a serious problem in some cases, and land birds like the black redstart and the peregrine falcon. It is also in the southernmost range of the common murre (adopted as the symbol of the nature reserve) and is one of the few breeding locations of the band-rumped storm petrel.
A new endemic species of snail, Oestophora Species nova was described in 2015.
In the 1950s the islands were an important spawning ground for .
In 1808, wrecked on Berlenga Grande in a gale, though without loss of life.Hepper, David J. (1994). British Warship Losses in the Age of Sail, 1650–1859, p. 123. Rotherfield: Jean Boudriot.
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