The Patagonian Desert is the largest desert in Argentina and is the 4th largest desert in the world by area. It is located primarily in Argentina with small parts in Chile and is bounded by the Andes, to its west, and the Atlantic Ocean to its east, in the region of Patagonia, southern Argentina. To the north the desert grades into the semi-aridCuyo region and the Dy and Humid Pampas. The central parts of the steppe are dominated by shrubby and herbaceous plant species albeit to the west, where precipitation is higher, bushes are replaced by grasses. Topographically the deserts consist of alternating tablelands and massifs dissected by river valleys and canyons. The more western parts of the steppe host lakes of glacial origin and grades into barren mountains or cold temperate forests along valleys.
Inhabited by hunter-gatherers since Pre-Hispanic times the desert faced in the 19th century migration of Mapuches, Chileand, Argentines, Welsh and other European peoples transforming it from a conflict borderland zone to an integral part of Argentina with cattle, sheep and horse husbandry being the primary land use.
Before the Andes were formed, the region was likely covered by temperate forests. However, after the formation of the Andes, ash from nearby volcanoes covered the forests and mineral-saturated waters seeped into the logs, thus fossilizing the trees and creating one of the world’s best preserved petrified forests in the desert’s center. The Patagonian is mainly composed of gravel plains and plateaus with sandstone canyons and clay shapes dotting the landscape, sculpted by the desert wind. The region encompassing the desert, however, has many diverse features. Ephemeral rivers, lakes, and drainage deposits from the Andes’ spring melt form annually, hosting a variety of waterfowl and aquatic grasses. A variety of glacial, fluvial, and volcanic deposits are also found in the region and have significantly affected the desert’s climate over time, especially contributing to the gravel sediments covering parts of the Patagonian.
Despite the harsh desert environment, a number of animals venture into and live in the Patagonian. Some only live on the more habitable and geographically-varied outskirts of the desert, where food is more abundant and the environment less hostile, but all are found within the region encompassing the Patagonian. The flora of the region is quite common for its climate and includes several species of desert shrubs. Aquatic grasses and larger flora exist on the outskirts of the desert and around the ephemeral lakes that form from the Andes’ runoff.
The desert has hosted various indigenous peoples in its past, as evidenced by cave paintings in the area. The earliest inhabitants of the desert known by name are those of the Tehuelche complex. Tehuelches lived as hunter-gatherers and did not practise agriculture in lush valleys found in the desert. In the 18th and 19th centuries the northern part of the desert came under Mapuche influence during a process of Araucanization. Mapuches came to practise horse husbandry in the northern part of the Patagonian steppe. In the few decades before and after 1900 the less dry parts of the Patagonian steppe experienced a sheep farming boom, transforming the region into one of the world’s greatest exporters of ovine products.
From the mid-19th century onwards several Argentine and European settlements, some of them sporadic, appeared at the edges of the desert. In the 1870s the Argentine army undertook the Conquest of the Desert campaign, massively defeating Mapuche warlords. The Conquest of the Desert was followed by a sharp decline in the indigenous population of the desert; some were chased into Chile and peripheral areas in the Andes. It is estimated that the Conquest of the Desert caused the death of about 1000Native Americans. Additionally 10 000 Native Americans were taken prisoner of whom 3 000 ended up in Buenos Aires separated by sexes to avoid their procreation. The boundary treaty of 18821 between Argentina and Chile bought most of the desert under definitive Argentine sovereignty, previously Chile had claimed varying now Argentine areas under claims of inherited colonial titles.
The area is sparsely populated today and those that do live here survive mainly by the raising of livestock such as sheep and goats. Resource mining, especially of oil, gas, and coal in parts of the region, is another way humans interact with and influence the desert environment.