Deserts of South America: Complete Guide to 6 South American Deserts

South America contains six notably different desert and dryland systems, each shaped by a different mix of ocean currents, mountain barriers, seasonal wind belts, local geology, and water scarcity. One desert can go years with almost no measurable rain, another may flood during El Niño, while another is better described as a desert-like sand country than a true desert.

6 articles in South America

The Atacama Desert is the dry benchmark most people know. The Sechura Desert sits on the same cold Pacific margin but behaves in a more erratic way. La Guajira Desert is a hot, windy coastal desert facing the Caribbean. The Monte Desert is a shrub desert on the eastern side of the Andes. The Patagonian Desert is a cold steppe desert built by rain shadow and relentless wind. Then there is Jalapão, where dunes and seasonal dryness create a desert image even though the wider region still belongs to the Cerrado domain and carries more water than a classic desert should.

Maps make the continent look tidy; on the ground, it is not that neat. Desert borders in South America often fade rather than stop. A dry coast turns into a fog-fed slope. A sand plain gives way to thorn scrub. A cold steppe grades into shrubland. Some limits change from one atlas to another, which is normal for regions where climate, relief, and vegetation transition gradually instead of ending at a fixed line.

Across these six landscapes, location, climate, landforms, plants and animals, and position within the wider arid diagonal reveal clear regional differences. Cold-current deserts cluster on the Pacific side. Rain-shadow deserts stretch east of the Andes. Desert-like sandy country appears inside Brazil for a very different reason.

How South America Builds Deserts

South America’s arid regions are shaped by several major climate controls. The first is the Humboldt Current, the cold Pacific flow that chills the air along Peru and Chile. Cold air holds less moisture than warm air. It also helps produce temperature inversions, where a cooler layer near the surface blocks rising air and weakens cloud growth. The result is familiar on the Pacific margin: fog, low cloud, and very little rain.

The second control is the Andes. Those mountains form a major barrier to moisture transport. Moist air from the Pacific or the Atlantic does not cross them evenly. On some flanks the Andes force moisture out of rising air. On the lee side, dry conditions dominate. West of the Andes, the coast can stay dry because the cold ocean and subtropical high pressure keep rain weak. East of the Andes, places like Patagonia and large parts of the Monte turn dry because the mountains remove moisture from westerly air before it reaches the steppe and basin country beyond.

A third control sits farther north: the trade-wind belt. In La Guajira, strong winds, high evaporation, sparse river flow, and a hot coastal setting combine to produce desert and semi-desert conditions on the Caribbean edge of the continent. There, dryness is shaped by heat, persistent wind, and very uneven seasonal rain rather than by the Humboldt Current.

Desert history also varies. Some South American deserts are ancient in geomorphic terms. The Atacama, for example, is often treated as one of the oldest non-polar deserts on Earth, with hyper-arid conditions established over very long spans. Others are dry but less stable. The Sechura can be transformed by strong El Niño years. Jalapão can look parched and sandy in the dry season, yet it is cut by rivers, springs, and wet veredas.

What Counts as a Desert Here, and What Does Not

Classification becomes difficult when sandy, semi-arid, and truly desert landscapes are grouped together. A climatological desert usually means very low rainfall and high aridity. A xeric shrubland may look desert-like without matching the same dryness. A steppe desert can support more plant cover than a bare dune field. A savanna with dunes can still be dry-season harsh without being a true rainless desert.

That matters especially for Jalapão. Its famous dunes create a desert-like landscape, but it does not behave like the Atacama or even like La Guajira. It has a strong wet season, many clear-water streams, spring-fed pools called fervedouros, and broad Cerrado vegetation around the sand fields. It is better treated as a desert-like microregion with striking dunes than as a textbook hyper-arid desert.

Sechura needs a similar caution, though for a different reason. Some maps use a small strict core, while others use a much broader coastal belt. That is why the reported size of Sechura can vary widely from one source to another. The place is real; the boundary is what shifts. Its defining features are low rainfall, coastal aridity, dunes, dry plains, and periodic El Niño disruption.

South American Deserts Compared Side by Side

The phrase South American deserts covers several distinct dryland types: a cold ocean desert, a flood-prone coastal desert, a hot trade-wind desert, a shrub desert, a cold steppe desert, and a desert-looking savanna sand country. Their climates and surface processes differ substantially across the continent.

Atacama Desert

The Atacama Desert sits in northern Chile and stretches for roughly 1,000 to 1,100 kilometers along the Pacific side. Depending on the boundary used, the desert is often placed at around 105,000 square kilometers for its core Chilean extent, while broader regional definitions can push the number higher. The Atacama is the driest benchmark in South America and is often regarded as the driest non-polar desert region on Earth.

Why the Atacama Is So Dry

Three controls work together here. First, the Humboldt Current cools the lower atmosphere along the coast. Second, the subtropical high-pressure belt favors descending air rather than rising, rain-making air. Third, the Andes help cut off moisture from the east. Together, these controls strongly suppress rainfall. In many parts of the desert, average annual rainfall is around 15 millimeters or less. In the hyper-arid core, some studies place annual precipitation below 2 millimeters.

Despite its extreme dryness, the Atacama contains several distinct ecological settings. It has fog-influenced coastal zones, salars, high volcanic basins where flamingos feed, and lower barren plains where salt and nitrate dominate the surface. Adapted life is concentrated in places where moisture, altitude, or groundwater create suitable conditions.

Landforms, Elevation, and Surface Detail

The Atacama is not one endless sand sheet. Much of it is a stone, salt, and sediment desert. Gravel plains, alluvial fans, salar basins, lava surfaces, badlands, and dry channels often matter more than mobile dunes. The Pacific margin has coastal ranges and fog-prone slopes. Inland, the terrain rises toward high plateaus and volcanoes. Some sectors are low and stark. Others are high enough to have alpine conditions while remaining desert-dry.

That vertical range creates marked ecological differences. Lowland sectors may be dominated by bare ground and salt crust, while high Andean basins support lagoons, puna grasses, and a different suite of birds and mammals. Elevation therefore changes both landforms and habitats across the Atacama.

Fog, Salars, and Desert Life

Fog is an important moisture source along some Atacama coastal slopes, where it can sustain specialized plant communities called lomas. These communities are localized and depend on atmospheric moisture rather than regular rainfall, showing how non-rainfall water inputs can shape desert ecology.

In the interior, salars are another defining feature. Closed basins trap dissolved minerals, and evaporation concentrates salts into bright crusts, shallow brines, and polygonal surfaces. On higher salar systems, flamingos feed in mineral-rich lagoons surrounded by extremely dry terrain.

Plants, Animals, and Adaptation

At the harshest sites, plant cover is extremely low. Yet the desert is not empty. In moister micro-sites or along elevation gradients, tamarugo, cushion plants, salt-tolerant shrubs, and high-altitude grasses occur. Animal life includes vicuñas, flamingos, foxes, lizards, hardy invertebrates, and microbes. Microbial life in Atacama soils has drawn global scientific attention because the desert provides natural conditions for studying survival under severe dryness.

Another Atacama feature is the occasional desert bloom. When unusual rain arrives in the right season, dormant seeds can germinate and cover parts of the desert with flowers. It does not happen every year or in every part of the desert, but these rare wet events can strongly affect local ecology.

The Atacama in South America’s Arid Geography

The Atacama represents the dry end-member of South America’s arid landscapes. Sechura is also dry but more sensitive to El Niño rainfall, while Jalapão has a seasonal water regime that separates it from true desert climates. The Atacama therefore provides a clear contrast between a hyper-arid core and wetter seasonal drylands.

The Atacama is also important for astronomy. Its high elevation, low humidity, and clear skies are among the reasons facilities such as ALMA operate there, using the dry atmosphere for observations that are difficult in wetter regions.

Sechura Desert

The Sechura Desert runs along the northern Pacific side of Peru, mainly across parts of Piura and Lambayeque. Some descriptions use a narrow core around the Sechura plain. Others stretch the label across a much broader coastal ecoregion. That is why one source may describe a modest desert unit while another quotes an area close to 50,000 square kilometers. Both refer to the same dry system at different map scales.

A Coastal Desert Shaped by Strong Climate Variability

Like the Atacama, Sechura sits under the influence of the cold Pacific current. The ocean cools the lower atmosphere and keeps rainfall weak across much of the coast. In low areas, annual precipitation can fall in the range of 20 to 100 millimeters, with somewhat higher values on margins and raised ground. Sechura, however, does not maintain hyper-aridity as consistently as the Atacama.

When strong El Niño events arrive, the desert can change quickly. Water that is absent most years can spread across flats and basins. During extreme episodes, large temporary water bodies may form in the Sechura system. Climate variability therefore has a major influence on the desert alongside its low average rainfall.

Relief, Dunes, and the Shape of the Plain

Sechura includes sand sheets, dunes, flat arid plains, shallow depressions, dry channels, and coastal sectors influenced by the nearby ocean. Wind moves sand, while river floods and periodic water accumulation also reshape parts of the surface.

The Sechura Depression adds another layer to the desert’s geography. Low-lying terrain controls drainage, salt accumulation, and flood behavior. During wet years, these topographic lows can become areas of temporary water accumulation.

Why Sechura Is Ecologically More Mixed Than It Looks

The wider Sechura system and its ecoregional transitions include links to dry forest, scrub, ephemeral herbs after rain, and saline or marsh-like environments in specific low sites. Some plants respond rapidly to moisture pulses, while others persist in scattered form through long dry phases.

Sechura can change rapidly after unusual rain. Dormant seeds germinate, temporary surface water appears, insects increase, and birds respond to the short-lived rise in food and habitat availability. As conditions dry, these wet-phase effects contract again.

Climate and Rainfall Range

A single rainfall number cannot describe Sechura accurately, so a range is more useful. In its driest low sectors, annual precipitation may sit around 20 to 50 mm. Elsewhere, especially on slightly higher or more interior margins, it may climb toward 100 to 200 mm. That spread helps explain the mixed vegetation and the variable desert boundary. Temperature also stays moderated by the nearby Pacific more than in many inland deserts.

Sechura is a coastal desert system with sandy surfaces, low rainfall, and strong sensitivity to ocean-atmosphere anomalies. That sensitivity distinguishes it from more stable hyper-arid systems.

Sechura’s Role in the Pacific Dry Corridor

Sechura forms part of the Pacific dry corridor where cold-current aridity occurs alongside strong climate variability. Its climate demonstrates that dry on average does not mean equally dry every year.

The Atacama and Sechura represent different expressions of Pacific coastal aridity. The Atacama reaches much more stable and extreme dryness, while Sechura shows variability inside aridity through its stronger response to El Niño.

La Guajira Desert

The La Guajira Desert occupies the northernmost tip of South America, mainly in Colombia with a smaller extension into Venezuela. It faces the Caribbean rather than the Pacific. The setting is hot and windy, and in places coastal dunes extend directly toward the sea.

Hot, Windy, and Dry for Different Reasons

La Guajira is usually described as arid to semi-arid. In the driest northern sectors, annual rainfall often stays below 300 mm, while other parts of the peninsula receive more. Some agroclimatic work for Uribia, for example, places local annual rainfall in the 300 to 600 mm band, paired with very high evapotranspiration around 2,000 mm. Even where rain arrives, high evaporation maintains strong water stress.

Trade winds are a major part of the region’s climate. They help keep the landscape dry and mobile, contribute to sand movement, and support high coastal evaporation. Wind speeds in parts of La Guajira are also among the strongest regularly recorded in the Colombian Caribbean.

A Desert by the Caribbean, Not by the Pacific

La Guajira demonstrates that South American desert geography is not limited to the Pacific coast. Its Caribbean-edge aridity is built not by the Humboldt Current but by heat, wind, scarce surface water, and a long dry season.

Coastal dunes, low rocky headlands, salt flats, seasonal drainage lines, and open thorn scrub make up much of the region. The landscape changes from beach-dune systems to scrub plains and rocky sectors over relatively short distances.

The Macuira Contrast

La Guajira also contains a strong internal contrast at Macuira. The Macuira massif rises as an oasis-like mountain block inside the semi-desert of Alta Guajira. Atmospheric moisture can condense there and support pockets of greener vegetation, including cloud-forest conditions on higher ground.

La Guajira therefore includes microclimates, local relief effects, and ecological pockets that depend on the interaction between wind, elevation, and coastal moisture.

Vegetation, Wildlife, and Human Geography

Plant cover in La Guajira usually appears as xerophytic scrub, thorny bushes, cacti, sparse grasses, and salt-tolerant vegetation in selected areas. Trees are limited and closely tied to water availability. Animal life includes birds of dry coast and scrub, reptiles, goats in pastoral landscapes, and species adapted to heat and water scarcity.

The human geography is also part of the region. La Guajira is strongly associated with the Wayuu people, whose communities and land use have long been connected with this arid peninsula.

How La Guajira Differs From the Other Drylands

La Guajira stands apart as a hot Caribbean coastal desert. The Atacama is cooler and closely associated with altitude and salt basins. Patagonia is colder and wind-scoured. Monte is more shrub-dominated. Sechura is more sensitive to episodic flooding, while Jalapão is not a true desert in climate terms.

La Guajira is South America’s Caribbean desert, distinguished from the Pacific deserts by its hot coastal setting, trade winds, and seasonal rainfall pattern.

Monte Desert

The Monte Desert stretches across much of western and north-central Argentina, mainly along the eastern foothills of the Andes and adjoining basins. It is often split into Low Monte and High Monte. Taken together as a biome, the Monte covers roughly 460,000 to 470,000 square kilometers, with the Low Monte alone around 354,000 square kilometers and the High Monte close to 117,000 square kilometers.

A Desert of Shrubs, Not an Ocean of Sand

The Monte is mostly a shrub desert, marked by jarilla scrub, scattered grasses, cacti, and hardy woody plants adapted to dry soils, high evaporation, and large temperature swings. Some areas include alluvial fans, gravelly surfaces, badlands, or salt flats, but shrubland is one of the region’s most characteristic surface patterns.

This vegetation structure affects wildlife cover, soil behavior, water infiltration, and grazing pressure. A shrub desert interacts with wind and runoff differently from an open dune field.

Climate and Seasonal Pattern

The Monte is arid to semi-arid, with rainfall varying strongly by sector. Broadly, the numbers run from under 100 mm in the driest pockets to around 450 mm in less arid sectors, while the Low Monte is often placed in the 80 to 250 mm band. In much of the north and center, most rain falls during the austral summer. Farther south, seasonality becomes less pronounced and the climate becomes cooler and windier.

The Monte belongs to the great arid diagonal of South America, the dry belt that runs from the northwest toward Patagonia. Its dryness is tied to relief, continentality, and rain-shadow effects produced by mountain systems. The mountain-and-basin setting is a major control on its aridity.

Relief, Soils, and Dryland Structure

Piedmont zones, dry valleys, basin floors, saline depressions, and old alluvial surfaces create strong environmental gradients across the Monte. Small changes in topography matter because they control where runoff gathers, where salts accumulate, and where deeper-rooted shrubs can survive. A site with slightly better drainage may support one plant community, while a flatter saline floor may support another.

Aridity favors sparse organic matter, patchy crust development, salinization in low basins, and large areas where the surface can be fragile under heavy disturbance. The Monte does not need sand seas to qualify as desert terrain; persistent water deficit shapes the region directly.

Plants, Endemism, and the Monte Identity

Larrea, the jarilla shrubs, is one of the most characteristic plant groups of the Monte. Cacti, thorny scrub, Prosopis woodland in better-watered sites, and drought-adapted grasses also occur. Biogeographic studies have identified local endemism in plants and insects across parts of the region.

Shrub cover does not exclude the Monte from desert classification. Its vegetation structure differs from open sand deserts, but water deficit and aridity still define much of the region.

The Monte in South America’s Arid Diagonal

The Monte occupies the dry basin-and-foothill zone between Pacific coastal deserts and the Patagonian steppe. It supports a shrub matrix and grades into neighboring dry biomes while retaining its own desert characteristics.

It also forms a geographic transition between northern arid Argentina and the wider Patagonian system, linking basin, foothill, shrub-desert, and steppe environments across western Argentina.

Patagonian Desert

The Patagonian Desert, often called the Patagonian Steppe, spreads mainly across southern Argentina with smaller extensions into Chilean Patagonia. It is usually estimated at around 673,000 to 700,000 square kilometers, making it the largest desert in Argentina and one of the world’s largest cold desert landscapes.

A Cold Desert Built by Wind and Rain Shadow

Patagonia is a cold, wind-dominated desert and steppe system. Westerly air masses move in from the Pacific, rise over the Andes, lose much of their moisture, and descend drier on the eastern side. That classic rain-shadow pattern, reinforced by distance and open exposure, shapes the steppe. Annual precipitation often ranges from about 90 to 430 mm, with the lowest totals in the driest interiors and somewhat higher values near ecotones and uplands.

Temperature also matters. This is not a hot desert in the usual sense. Winters can be cold, frost is common, and the climate is generally described as temperate-cold arid steppe. Strong winds raise evaporation and increase heat loss for animals and people in exposed areas.

What the Surface Looks Like

Patagonia includes gravel plains, mesas, basalt plateaus, broad valleys, cliffs, canyons, and coastal sectors that descend toward the Atlantic. In many areas, stone and gravel dominate more than loose sand. Wind erosion, sparse vegetation, and long exposure contribute to extensive hard, open surfaces.

The Patagonian Desert differs visibly from the Monte. The Monte is dominated by shrubs and basins, while Patagonia is characterized by plateaus, wind, gravel plains, and long open distances.

Wildlife and the Steppe Food Web

The Patagonian steppe supports animals adapted to open, windy, low-productivity terrain. Guanacos are the best-known large native grazers. Darwin’s rhea, mara, foxes, condors, and many steppe birds also belong to the system. Conservation work in parts of Patagonia focuses on retaining these open-land ecological processes across large natural dryland areas.

Plant cover stays low and patchy, with grasses, cushion plants, and shrubs arranged according to rainfall, soil texture, and exposure. Small differences in moisture and wind can alter the local plant mix.

How the Patagonian Desert Differs From Atacama

The Atacama and Patagonian Desert are dry for different reasons. The Atacama is tied to the cold Pacific current, temperature inversion, salars, and extreme lack of rain. Patagonia is tied to mountain rain shadow, cold temperate conditions, gravel plains, and persistent wind.

The Patagonian example also shows that a desert does not need hot sand or sparse cactus vegetation. Deserts can be cold, partly grassy, and dominated by gravel or stone rather than dunes.

The Patagonian Role in the Continental Pattern

Patagonia shows how far the arid diagonal extends into the temperate south. It also demonstrates that the Andes create extensive east-side rain-shadow deserts as well as contributing to aridity on the Pacific side. Atacama and Patagonia therefore occupy different climatic categories despite both being arid.

Jalapão Microregion

The Jalapão Microregion lies in eastern Tocantins, Brazil. It is often described as a Brazilian desert because of its orange dunes, exposed sandstone, intense dry-season conditions, and sparse-looking vegetation in selected sectors. The wider region is often quoted near 34,000 square kilometers, while Jalapão State Park covers about 158,885 hectares. The desert label, however, needs care.

Why Jalapão Is Not a True Desert in the Same Sense

Jalapão is desert-like, not a classic low-rain desert. The region belongs to the Cerrado, South America’s vast tropical savanna domain. It has a pronounced dry season and wet season. Across Tocantins, annual rainfall commonly falls in the band of roughly 1,200 to 2,100 mm, far above the totals of the Atacama, Sechura, Monte, Patagonia, or La Guajira. In Jalapão itself, the dry months can become intensely parched, but the yearly water budget still separates it from a true desert climate.

The dry season runs roughly from May to September, while the wetter season spans October to April. In some weather averages for the park area, July and August rainfall drops close to zero, and daytime temperatures rise well above 35°C. These dry-season conditions explain the desert-like appearance, while the annual rainfall total places Jalapão outside a true desert climate.

Formation of the Jalapão Dunes

Jalapão’s dunes can reach around 30 to 40 meters, but they are not part of a classic continental sand sea system. They are mainly produced by erosion of the sandstone mass of Serra do Espírito Santo. Wind carries and reshapes the quartz-rich sand, forming the orange dune field within an exposed dry-season environment.

This shows how landform appearance and climate classification do not always match. A place can look like a desert without being one in the same meteorological sense as the Atacama. The distinction separates dune country from true desert climate.

Water in the Jalapão Landscape

The landscape can look dry and sandy, yet the region contains rivers, springs, waterfalls, and veredas lined with buriti palms. The fervedouros are spring-fed pools where upward water pressure makes floating easy. These water features clearly separate Jalapão from much drier systems such as the Atacama and Patagonian Desert.

Jalapão combines dry-season exposure with water-rich microhabitats, including springs, streams, wetlands, and groundwater-fed pools.

Vegetation, Wildlife, and the Cerrado Link

The plant cover around Jalapão belongs largely to the Cerrado mosaic: grasses, shrubs, twisted small trees, gallery forest strips near water, and wetland vegetation in veredas. The dune sectors look open and sparse, but the wider region is not botanically empty. The fauna reflects that mixed setting too, with Cerrado-adapted birds, mammals, reptiles, and aquatic life where springs and streams remain active.

Jalapão is best classified as a desert-like seasonal dryland within the Cerrado, not as a textbook desert equal to the Atacama. The distinction separates dune-rich seasonal landscapes from true desert climates.

Jalapão’s Desert-Like Status

Jalapão is a desert-looking dry landscape rather than a true desert. Its sand, seasonal drought, and visually arid terrain occur within a tropical savanna system that receives far more annual rainfall than South America’s true deserts.

Patterns That Connect the Six Landscapes

Three continental patterns connect these six drylands. The first is the Pacific arid margin. The Atacama and Sechura sit there, both linked to the cold ocean and weak rainfall. The second is the Andean lee-side pattern, where the Monte and Patagonian Desert occupy terrain east of mountain barriers. The third consists of the non-Pacific drylands, represented by La Guajira’s Caribbean aridity and Jalapão’s dune-rich tropical savanna setting.

The driest ground is not necessarily the windiest, dune fields do not always occur in the driest climates, and cold deserts can retain substantial plant cover. The process behind each desert label is therefore more informative than appearance alone.

Which of the Six Is the Driest

The Atacama is the driest of these regions by a wide margin in its core sectors. Hyper-arid areas can fall below 2 mm of annual precipitation, while many other sectors still sit around 15 mm or less. None of the other five consistently approaches that level of dryness. Sechura can be very dry but is less stable. La Guajira is arid but generally has higher annual totals. Monte and Patagonia are desert and steppe systems with more plant cover and usually more rainfall. Jalapão is not in the same climate class.

Which of the Six Is the Largest

The Patagonian Desert is commonly placed near 673,000 to 700,000 square kilometers. The Monte biome is also very large when Low and High Monte are considered together, but Patagonia remains larger as a desert-steppe region. Its size also shows that desert extent is not limited to hot climates.

Which of the Six Has the Most Complicated Classification

Sechura and Jalapão have the most complicated classifications, though for different reasons. Sechura has shifting map boundaries depending on whether the strict desert core or a broader coastal ecoregion is used. Jalapão looks desert-like but does not match a classic desert rainfall regime.

How the Six Drylands Differ in Surface Form

Climate alone does not fully distinguish these regions. Surface form matters as well. The Atacama is known for salars, volcanic plateaus, stony surfaces, and extremely barren ground. The Sechura mixes dunes and low plains with event-driven flood behavior. La Guajira pairs coastal dunes and salt-rich sectors with thorn scrub and rocky margins. The Monte is a shrub desert built around basins, fans, and dry scrublands. Patagonia is dominated by gravel, mesas, plateaus, and wind-exposed steppe. Jalapão contains dune country inside a spring-rich savanna mosaic.

Broad phrases such as “South American sand desert” can be misleading because several of these regions are not dominated by sand. A desert can be a salt desert, a shrub desert, a steppe desert, or a dune-rich dryland.

Plants and Animals Across the South American Dry Belt

Deserts in South America support life in different ways. The Atacama relies on microhabitats, fog zones, salar wetlands, and high-elevation niches. The Sechura depends more on episodic moisture pulses. La Guajira organizes life around wind, thorn scrub, seasonal water, and refuges such as Macuira. The Monte supports a structured shrub matrix. Patagonia supports broad open-steppe food webs. Jalapão ties dry-season sand to a much wetter seasonal water network.

Desert life follows water pathways, not just rainfall totals. Water can come as fog, brine-fed wetlands, snowmelt from uplands, rare storm runoff, groundwater discharge, or seasonal flood pulses. These sources can support habitats that annual rainfall totals alone do not explain.

Biodiversity Examples Across the Six Drylands

• Atacama: flamingos in high salars, vicuñas in uplands, lomas vegetation where fog can be captured
• Sechura: ephemeral vegetation and flood-responsive ecological pulses during strong wet anomalies
• La Guajira: thorn scrub, cacti, dry-coast birds, and greener mountain habitat at Macuira
• Monte: jarilla dominance, cactus, Prosopis in better-watered sites, dryland insects with local endemism
• Patagonia: guanaco, rhea, foxes, condors, open-steppe grasses and shrubs
• Jalapão: Cerrado flora, buriti palm wetlands, sparse dune vegetation, and spring-fed aquatic habitats

Climate and Landform Patterns Across South America’s Drylands

Three features distinguish South America’s main drylands: the source of aridity, surface form, and the stability of dryness from year to year. Together they separate the six landscapes by climate and geomorphology.

The Atacama combines cold-current influence and mountain barriers with salt and stone surfaces and stable long-term aridity. Sechura combines a cold coastal setting with sandy low plains and strong El Niño sensitivity. La Guajira is shaped by heat and trade winds, coastal dune-scrub terrain, and uneven seasonal rainfall. The Monte reflects Andean lee-side dryness, shrub desert, and broad biome transitions. Patagonia combines a cold rain shadow, gravel steppe, and persistent wind stress. Jalapão combines seasonal tropical drought, sand from eroding sandstone, and a water-rich annual cycle despite its desert-like appearance.

These differences reflect climate and landform rather than a single desert type repeated across the continent.

Desert Terms for South American Drylands

Rain Shadow

A rain shadow forms when mountains force moist air upward, rain falls on one side, and drier air descends on the other side. This helps explain the Monte and Patagonian Desert.

Hyper-Arid

Hyper-arid means an extreme level of dryness beyond ordinary desert conditions. Among these South American drylands, the term applies most clearly to the Atacama.

Xeric Shrubland

This describes dry shrub-dominated terrain. It fits much of the Monte better than the image of an open sand sea.

Fog Oasis

A fog oasis is a local green zone sustained by atmospheric moisture rather than regular rain. Parts of the Atacama and the Macuira massif in La Guajira show how atmospheric moisture can support local vegetation under otherwise dry conditions.

Seasonal Dryland

A place can be very dry for months and still not count as a true desert on an annual water budget. That description fits Jalapão.

Where Desert Boundaries Change

Many South American drylands have gradual transition zones. The Atacama grades into higher puna systems and coastal fog slopes. Sechura transitions into dry forest and coastal lowland mosaics. La Guajira shifts between hard desert sectors and greener mountain refuge zones. The Monte grades into Chaco, Puna, and Patagonia. Patagonia links to Andean and coastal transitions. Jalapão changes from dune sectors into river corridors, wetlands, and wider Cerrado vegetation.

These edge zones often concentrate biodiversity, water access, and land use. They are also where climatic and ecological classifications overlap most strongly, making exact desert boundaries less consistent between maps.

The number of deserts in South America depends partly on how strict the classification is. The continent contains a chain of drylands built by different forces. Atacama represents the hyper-arid extreme. Sechura is a variable Pacific coastal desert. La Guajira is a hot Caribbean desert. Monte is the shrub desert of Argentina. Patagonia is a large cold steppe desert. Jalapão is a desert-like Cerrado landscape whose seasonal rainfall and abundant water features separate it from true desert climates.