Patagonian Desert

The Patagonian Desert, also called Patagonian Steppe, is an arid landscape in southern South America.

Location and climate

The Patagonian desert occupies the south of the American continent including in the north of the island Isla Grande de Tierra del Fuego, and some islands in the eastern part of the Tierra del Fuego archipelago. As northern boundary of the area of the Rio Colorado is considered, the forest zone on the eastern slope of the Andes forms the western, the coast of the Atlantic, the eastern boundary of the area. Much of the Patagonian desert is located in the five southernmost provinces of the Republic of Argentina ( Tierra del Fuego, Antartida e Islas de Atlantico Sur, Santa Cruz, Chubut, Rio Negro, Neuquén ), in addition also includes the south of the Rio Colorado location of the Buenos Aires Province ( Partido Patagones ) for Patagonian desert. The proportion of the Republic of Chile in the Patagonian desert is limited in addition to some valleys in the regions X, XI and XII on the narrow coastal strip along the Magellan Strait east of Punta Arenas. With an area of ​​approximately 673,000 km ², the Patagonian desert is the most extensive dryland America.

The south of the fortieth degree of latitude year-round prevailing westerly flow causes the clouds formed over the South Pacific for the most part on the western slope of the Andes abregnen, in addition the ice fields of the Campo de Hielo Sur and the Campo de Hielo Norte lead to a further negative effect. The cold Falkland Current in the southern Atlantic prevents the formation of clouds over the Atlantic. The southern exposure leads to long, cold winters, where frost is not uncommon. Snowfalls are known but rare. The average annual temperature is about 12 ° C.

The seasonal distribution of rainfall shows no extremes, the maxima are usually in the months of January to April. The geographical distribution shows a clear east-west and a less pronounced north-south gradient, the maximum values ​​of around 300 mm of rainfall per year are reached around Viedma in the northeast of the area, are in the extreme rain shadow areas on the eastern slope of the Andes recorded in individual years partly less than 100 mm rainfall. The continuous West wind carries through desiccation of the soil, when the extreme drought.

Geology

In terms of geomorphology, the area is dominated by the Meseta called hills and wide plains along the Atlantic Ocean, occur frequently mesas, which are divided by the valleys often only intermittently flowing watercourses. The soils are mostly formed of coarse, nutrient-poor sediments, fine-grained materials and organic substances found only in areas with low air movement.

It is characterized by numerous occurrences of petrified wood, which ( rich in silica usually) in sediment- covered, dead tree trunks during the formation of the Andes can be explained by the penetration of mineral-rich fluids. Some sites - such as the Monumento Natural Bosques Petrificado - have now been placed under protection. Such as coal near Rio Turbio and petroleum near Comodoro Rivadavia - - Besides these obvious witnesses greater forest cover also various natural resources to speak as well as the sites of remains of herbivorous sauropods on the Río Limay for a dramatic change in the vegetation more than 50 million years ago.

Flora and Fauna

The natural flora of the area consists mainly of grasses of the genera of the spring grasses and bluegrasses, isolated stocks to indicate shrubs of the genera Benthamiella ( family Solanaceae ) and Acantholippia (Family verbena family). Along the rivers and lakes on the eastern slopes of the Andes are also ways to find out which need more moisture.

Agriculture and forestry are of no importance, which are often encountered poplars are for the windshield.

In addition to the held under extensive livestock farming livestock - mainly sheep, horses and donkeys - to a wide range of stocks of wild animals have received, but the number of animals due to climatic conditions is relatively low. Typical bird species Darwin Nandu and burrowing owl, are conspicuous beyond different types of birds of prey. The mammals are represented by different species of the genus comb rats, Maras, guanacos and dwarf armadillos; Predators are Patagonian weasel, Argentinian Kamp fox and Puma.

History

Sites such as the Cueva de las Manos occupy the early settlement of this area for at least 9,000 years. Since the climatic conditions are likely to have differed at that time not significantly different from today's, it can be assumed that the former settlers lived nomadic. The coast of Patagonia was first visited in 1520 by Ferdinand Magellan, who spent the southern winter 1520 at today's Puerto San Julián. Here, members of the expedition met with members of indigenous peoples, which Antonio Pigafetta called Patagonians due to their body size. In 1578 Sir Francis Drake reached this bay. The settlement of the area south of the Rio Colorado began only in the second half of the 19th century, many towns were founded in the 20th century.