Biomes

Ecoregions of Chile

June 15, 2013, 2:37 am
Content Cover Image

Southern Andean steppe meets glacial meltwater, Torres del Paine National Park. @ C.Michael Hogan

Chile has eight ecoregions that occur entirely or partly within its borders on the mainland and three ecorgions offshore:

  1. Sechura desert
  2. Atacama desert
  3. Central Andean dry puna
  4. Chilean matorral
  5. Southern Andean steppe
  6. Valdivian temperate forests
  7. Patagonian steppe
  8. Magellanic subpolar forests

Off the mainland:

  1. San Félix-San Ambrosio Islands temperate forests
  2. Juan Fernández Islands temperate forests
  3. Rapa Nui and Sala-y-Gomez subtropical broadleaf forests

Chile is bordered by the Humboldt Current large marine ecosystem.

Sechura desert

The Sechura desert is the most extensive desert strip on the western coast of South America. This ecoregion occupies the western subtropical portion of South America in the form of a longitudial coastal strip that extends along 2000 kilometers of Peruvian territory and just over the boder into most northern part of Chile.

Although it has been subject to much intervention, it still contains singular plant associations that shelter species endemic to the desert such as lomas vegetation. The ecoregion also serves as an important corridor for migratory birds. Human population density is high in this area and although there are a few protected parks, urban expansion poses a major threat to this ecoregion.

Atacama desert

The Atacama Desert ecoregion occupies a continuous strip for nearly 1600 km along the narrow coast of the northern third of Chile from near Arica (18°24' S) southward to near La Serena (29°55' S). This desert is a sparsely populated virtually rainless plateau, running east from the Pacific Ocean to the Andes Mountains. The average width is less than 100 km.

In many areas rainfall has never been recorded, and the Atacama is considered one of the driest deserts in the world. Consequently, an extremely arid, almost barren, landscape predominates.

Despite the aridity of this desert, some cacti (Eulychnia), perennials (Nolana), and mesquite (Prosopis) occur in basins where occasional water accumulation occurs. Relatively few animal species have adapted to this arid environment and therefore, faunal diversity and density is extremely low. Even bacteria are scarce, and in many portions of the desert insects and fungi are absent. The intrinsic value of the Atacama Desert's plant and animal communities lies in the unique nature of their composition, the high levels of endemism and remarkable species adaptations for survival in some of the Earth's most demanding abiotic conditions.

The region has been moderately affected by roads and mining operations. The northern area of the ecoregion has been especially affected by overgrazing of domestic livestock, collection of firewood, and commercial gathering of rare plants, including the Chilean wine palm, various cacti and bulbs.

Some nearby areas have archaeological importance. The beauty and rarity of the lomas formations provide opportunities for tourism combined with scientific studies. If the impact on the delicate communities is controlled through supervision, lomas formations can be enjoyed by the public and preserved. Environmental education on the importance, rarity, and the unusual characteristics of these natural resources is desperately needed. For example, Quebrada El León needs some recuperation from overuse and could become a lasting and informative oasis as a nature reserve for residents of Caldera and Copiapó.

caption Atacama Desert, Chile. Source: NASA Three protected areas exist within the extreme desert region. Pan de Azúcar National Park (established in 1986, IUCN category II) covers 438 square kilometers (km2). It has been recommended that this park be expanded northward to include Quebrada Esmeralda (25°50' S) and Quebrada de Las Lozas (25°41' S), which would protect areas very rich in cacti diversity. La Chimba National Reserve (IUCN category IV) of 30 km2 was recently established and lies approximately 15 km north of Antofagasta. Pampa del Tamarugal National Reserve, 1023 km2 in size, is one of the key areas for the conservation of the threatened tamarugo conebill (Conirostrum tamarugense).

Central Andean dry puna

The Central Andean Dry Puna is located in the southern part of the Andean Cordillera Occidental in the countries of Argentina, Bolivia, and Chile. The area encompasses snow-capped peaks, volcanoes, salt flats, lagoons, and high plateaus. The ecoregion includes the provinces of Tarapaca, Antofagasta, and Atacama in Chile.

The vegetation is characteristically tropical alpine herbs with dwarf shrubs, and occurs above 3,500 meters (m) between the tree-line and the permanent snow-line. Dry puna is distinguished from other types of puna by its annual rainfall, or lack of rainfall. This ecoregion receives less than 400 millimeters (mm) of rainfall each year, and is very seasonal with an eight-month long dry season.

The Central Andean Dry Puna is a unique ecoregion with flora and fauna highly adapted to the extreme temperatures and altitudes. The region contains forests of Polylepis, the only arborescent genus that occurs naturally at high elevations. Various species of Andean camelids are also found in this region.

The Andean puna has been highly affected by livestock grazing for centuries. The natural vegetation] has been severely affected by grazing, burning, firewood collection, and clearance for cultivation. The camelids, goats and sheep in the area degrade the herbaceous vegetation, making the life cycle for the plants difficult to complete. The clearing of Polylepis forest for agriculture, firewood collection, and burning for pasture is an important threat to the endemic fauna, especially birds.

Chilean matorral

caption Parque Nacional de Campana, Chile Photograph by David Olson The Chilean matorral constitutes a 100 kilometer-wide strip extending along the central part of the Chilean coast.

The region has various endemic plant species with affinities to the tropics, the Antarctic and the Andes. About 95% of the plant species are Chilean endemic, including Gomortega keule, Pitavia punctata, Nothofagus alessandrii and Jubaea chilensis. The Chilean matorral has several threatened plant species; some endangered species are Adiantum gertrudis, Avellanita bustillosii and Beilschmiedia berteroana.

There are a significant number of endemic reptiles found in habitats ranging from rocky slopes to arid scrub.

The ecoregion has been severely affected by fire, mining, deforestation, overgrazing, garbage dumps, urbanization, air pollution, water pollution and soil contamination. Unfortunately this ecoregion is the least protected region in Chile.

Southern Andean steppe

The Southern Andean steppe ecoregion forms a continuous region along the dry southern Andes from Catamarca, La Rioja, San Juan, Mendoza and Neuquén provinces of Argentina and limiting areas of Chile between latitudes 27°S and 39°S. At these latitudes the Andes are formed by several parallel ranges, the most important being the Cordillera Principal, the Cordillera Frontal and the Precordillera from west to east.

The Andean steppe limits to the north with the central Andean punas and to the south with the Valdivian temperate forest and the Patagonian steppe, but it also extends as interrupted islands over mountains of these regions forming complex ecotones. The eastern limit is the transition to the lower altitude and warmer Argentine Monte desert, and the western limit to the lower Chilean matorral and Chilean winter-rain forest. The lower altitudinal limits of the ecoregion range from approximately 3500 meters (m) in the north to 1800 m in the south.

This ecoregion has its terrain at high altitudes that are not suitable for farming, and has several more or less protected areas through all its length, so there has been relatively little anthropogenic habitat loss in the area.

The south Andean steppe is not seriously threatened by habitat conversion at the present time. However, a marked increase in ecotourism and mountain sports such as climbing or skiing can be observed on several major mountains of the region.

Valdivian temperate forests

caption Alerce trees, Lenca, Chile Photograph by Marco Cortez This ecoregion is located in the southern cone of South America. It covers a narrow continental strip between the western slope of the Andes and the Pacific Ocean, running from 35° to 48° south latitude.

The Valdivian temperate forests and the more hygrophilous vegetation of the Mediterranean area of central Chile, represent a true biogeographic island separated from climatically similar areas by extensive ocean barriers and deserts.

The Valdivian temperate forest is characterized by its extraordinary endemism (e.g., 90% at the species level and 34% at the genus level for woody species) and the great antiquity of its biogeographic relationships.

Its taxons show close philogenetic relationships dating back to the early Tertiary, with Gondwanic taxons of Oceania forming more recent relationships with Neotropical taxons, separated from other biotas in South America by the great mountainous barrier of the Andes.

The region's ecosystems are frequently threatened and degraded. Urgent action has been recommended to restore the area's ecology and to preserve its remaining habitats.

Upon the arrival of the Spaniards, most of the area defined as the Valvidian ecoregion was effectively covered by forests with few open areas being cultivated by indigenous Mapuche groups. Currently, the forest cover has declined by one-third of the estimated area at the arrival the Spanish colonists, with a current area of about 12,600,000 hectares. The remaining forested area corresponds to an area (about 50%) of secondary forests. There are few remaining primary forests, especially in the coastal range. If the current rates of deforestation outside the areas of protection continue, the forest will disappear within the next 20 years.

The National Parks in the temperate forests of Chile and Argentina are considered pioneer protected areas in Latin America. Some of these Parks were established in the early 1900s. There are more than fifty parks, reserves and monuments protecting more than 10 million hectares in the temperate region of Chile. There is a great disparity between the distribution of these protected areas and the geographic distribution of trees and vertebrate species. The lowest percentage of protected areas (< 10%) is found in the areas with the highest biodiversity in Chile, between 35.6° and 41.3°S. Most of the protected areas within these latitudes contain the greatest wealth of species found above 600 m, where physical processes that produce impoverished speciation and endemism are accentuated. In addition, the areas with the greatest wealth of species are found precisely in areas with high human density, and thus there is great pressure from agriculture and plantation forestry. The protected areas in the Andes of Chile and Argentina represent 99% of the total surface area protected in the southern part of South America, in contrast to protected areas in the coastal range at the same latitude. The Andean forests are more impressive than the coastal forests, due to vistas of imposing volcanoes, great lakes, and small mountain lagoons, based on the prevailing landscape criteria used when creating Andean parks. There are no protected areas in the intermediate depression, with the exception of a small municipal park near Puerto Montt. caption Patagonian steppe, western Chile near Argentine border. Source: C.Michael Hogan

Patagonian steppe

The Patagonian steppe ecoregion mainly covers the Patagonia region of Argentina from the Atlantic Ocean shore to barely across the border into Chile.

This steppe is bordered on the west by the cold temperate forest slopes of the Andes, and on the east by the east by the Atlantic Ocean. It extends north-west as shrubland steppe and to the north as thorn thicket, gradually making the transition to Argentine Monte.

This area is a cold desert scrub steppe, with very high wind velocities throughout the year as well as year around frosts likely.

This ecoregion has high levels of endemism in both plants and animals.

Magellanic subpolar forests

caption Navarino Island nothofagus forest, Tierra del Fuego, Chile. @ C.Michael Hogan

The Magellanic subpolar forests is an ecoregion dominated by trees of the genus Nothofagus; this geographic zone covers the western part of the southern end of South America as well as the extreme southern parts of Argentina and Chile, known by the region Tierra del Fuego. The ecoregion is colder and in parts drier than the Valdivian temperate forests, and in general is floristically poorer. The fauna is related to that of the bordering ecoregions, especially to that of the Valdivian temperate forests and the Patagonian steppe. Nevertheless, its varied and majestic landscapes that include high mountain peaks, enormous icefields, and innumerable fjords are inhabited by unique and endemic animal and plant species that are sometimes abundant within this ecoregion.

The subpolar Nothofagus forests extend along the southern Andes Mountains and the Chilean archipelago from 47 ºS to the Cape Horn, including the regions of southern Aisen and Magallanes in Chile. In Argentina it only covers small surfaces of the western side of the province of Santa Cruz and the south of Tierra del Fuego from lake Buenos Aires to Staten Island. At this latitude three parallel regions, the Cordillera Patagónica Insular, the Cordillera Patagónica Occidental, and the Cordillera Patagónica Oriental form the Andes.

The northern end of the subpolar Nothofagus forests matches the limit of the Valdivian temperate forests and the eastern part of the Nothofagus forests borders the Patagonian steppe and the Patagonian grasslands. Towards the west the region is in contact with the cold southern Pacific Ocean, and on the high Andes vegetation is floristically related to the south Andean steppe appears in parts as interrupted islands.

This ecoregion has several more or less protected areas through all its length. The most important from north to south in Chile are the National Parks: Laguna San Rafael, Lago Jeinimeni, Bernardo O’Higgins, Torres del Paine, Alberto De Agostini and Cabo de Hornos.

San Félix-San Ambrosio Islands temperate forests

This group of relatively small oceanic islands, known as the Islas Desventuradas, is located approximately 850 kilometers (km) off the coast of Chile. The Desventuradas archipelago is formed by the islands of San Félix (26°17’SL-80°05’ WL) and San Ambrosio (26°20 LS-79°58’ WL), and is part of the ocean territory of Chile. It lies some 780 km north of the Juan Fernández Archipelago. The surface area of the first is 2.5 km2 and the surface area of the latter is 2.4 km2; they are separated by some 20 km.

Both islands are of volcanic origin, and both the terrestrial and marine flora and fauna are of great scientific interest, though we know little about them. San Ambrosio rises from the sea as sheer cliffs on almost all sides, is 4 km long by 850 meters (m) wide, and primarily basaltic. San Felix is slightly smaller and has two small peaks, reaching 193 meters (m), which are denuded by high winds. The vegetation is a miniature mosaic of matorral, barren rock, various size trees, and shrubs mixed with ferns and perennial herbs.

The Islas Desventuradas and the surrounding seas are not currently under type of protection provided by the government of Chile. The islands also have scientific and tourism potential and unsuccessful requests have been made to include at least San Ambrosio island in Chile’s National System of Protected Wildlife Areas.

Juan Fernández Islands temperate forests

The Juan Fernández archipelago is located 667 kilometers (km) off the coast of continental Chile in the south-eastern part of the Pacific Ocean and is of the few regions of the world where there was no permanent human settlements before 16th century. It comprises three main islands: Isla Robinson Crusoe (= Masatierra) at 33º 13' S, 78º 50' W, the closest to the mainland, Santa Clara, 1 km to the SW of Isla R. Crusoe, and Isla Alejandro Selkirk (= Masafuera) at 33º 45'S, 80º 46'W, 181 km further west.

The Juan Fernández Islands temperate forests ecoregion is exclusive to the Juan Fernández archipelago. As in most oceanic islands, its biota has a different combination of species than equivalent mainland areas. Because islands are difficult to reach, and each continental species has different dispersal capability, it is inevitable that islands will possess a non-representative sample of the species from the near continents. These forests contain a high percentage of endemism among vascular plants and possess the only endemic hummingbird known for oceanic islands. These unique taxa have evolved after the emergence of the islands, estimated in 1-5.8 millions of years, from the first colonizers.

caption Juan Fernandez Island, Chile Photograph by WWF/ J.C. Cardenas These islands were discovered in 1574 by the Spanish navigator Juan Fernández and are also known as Robinson Crusoe Islands, so named because the Scottish sailor, Alexander Selkirk, was self-marooned there for over 4 years, and his experiences served as the inspiration for Daniel Defoe’s famous novel.

Each island has its own somewhat distinct vegetation types. On Isla R. Crusoe the zones are: grasslands (0-100 m altitude), introduced shrubs (100-300 m), tall forests (300-500 m), lower montane forests (500-700 m), tree fern forests (700-750 m), and high brushwood on exposed cliffs (500-850 m). Isla Santa Clara has been denuded of shrubby vegetation and consists largely of grassy slopes throughout. On Isla A. Selkirk the zones are: grassland slopes (0-400 m) and deep ravines ("quebradas", 0-500 m), lower montane forests (400-600 m), upper montane forests (600-950 m), high brushwood (950-1100 m), and an "alpine zone" (1100-1300 m).

The importance of the flora of the Juan Fernández and its level of endangerment, as well as of its endemic fauna, are manifest by the Chilean government designation of this archipelago as a National Park in 1935 (administrated by the CONAF) and by the International Union for the Conservation of Nature (IUCN) designation of it as a World Biosphere Reserve in 1977, listed in their "most threatened" category. In addition, Bird Life International's identifies them as a critical conservation priority and they also appear in the WWF/IUCN's global study of Centers of Plant Diversity and Endemism. CONAF is actively working to save the endemic plants with support from the Chilean Government and several international organizations. However, the incipient restoration work seems insufficient to stall the effects of many aggressive introduced species.

Rapa Nui and Sala-y-Gomez subtropical broadleaf forests

Rapa Nui, also known as Easter Island, is one of the noteworthy islands on Earth. It forms the eastern geographic and cultural boundary of Polynesia. Located in the South Pacific at about 27º S latitude, Rapa Nui is 3,700 kilometers (km) west of Chile and about 2,200 km east of Pitcairn Island. It is the most remote inhabited spot on Earth.

Although paleobotanical studies suggest that the island was originally covered by palm and broadleaf forest, the island is now completely grass-covered, except for a few isolated stands of ornamental trees and shrubs. Rapa Nui is one of the most isolated islands in the world and thus has an interesting biogeographic and ecological history.

Rapa Nui is the youngest and westernmost of a chain of submarine volcanoes that probably formed as a volcanic hotspot track on the Nazca Tectonic Plate, located on the eastern side of the East Pacific Rise. The island is roughly triangular with an area of 166 square kilometers and a maximum elevation of 600 meters (m). It is composed of three main volcanic summits, Rano Kau, Poike, and Terevaka, as well as several smaller vents. The oldest is Poike, which erupted in two episodes, one occurring nine million years ago and the other 2.5 million years ago. Lavas from Rano Kau are as old as 940,000 years, and lavas from Terevaka are the youngest with flows as young as 300,000 years. The last volcanic eruptions on Rapa Nui occurred about 13,000 years ago.

caption Rapa Nui, Chile Photograph by John Morrison Sala-y-Gomez is a small reef 415 km to the northeast of Rapa Nui. It is only 300 m long at low tide, and shrinks to a mere 70 m at high tide. Constantly subjected to salt spray, only four species of terrestrial plants grow here. A small depression sometimes contains fresh water. Large populations of seabirds use this minute island for breeding. The terrestrial portion of the island is designated as a nature sanctuary.

Rapa Nui is the most isolated island in the Pacific and that makes it extremely valuable for studying the biogeographical distribution of species. It is currently the focus of numerous paleobotanical studies that are rapidly changing the understanding of its native flora.

Ferns are one of the few higher plants that can be considered indigenous to Rapa Nui. Just 4 of the 15 reported species are endemic: Doodia paschalis, Polystichum fuentesii, Elaphoglossum skottsbergii, and Thelypteris espinosae.

Triumfetta semitriloba, a woody shrub, was once thought to have been introduced to the island because it is an important textile plant. However, pollen analyses have shown that it existed on Rapa Nui at least 35,000 years ago. For some time, it was thought to be extirpated from the island, but at least four individuals were found in 1988.

The first Polynesians settlers reached Rapa Nui in the fifth century AD. It is uncertain when extensive deforestation began, though the island was basically deforested by the time the first Europeans arrived in 1722. Many exotic species have been introduced to the island. In recent studies, Zizka identified a total of 46 indigenous plant species of which nine were endemic and 166 introduced. Alien plants and animals make conservation and restoration of remnant natural communities and species challenging. For example, grazing by horses and other herbivores must be controlled before native species can regenerate. Recent efforts to reintroduce the toromiro have been undertaken by Kew Gardens.

Context

Ecoregions are areas that:

[1] share a large majority of their species and ecological dynamics;
[2] share similar environmental conditions; and,
[3] interact ecologically in ways that are critical for their long-term persistence.

Scientists at the World Wildlife Fund (WWF), have established a classification system that divides the world in 867 terrestrial ecoregions, 426 freshwater ecoregions and 229 marine ecoregions that reflect the distribution of a broad range of fauna and flora across the entire Earth.

References

  • M.A.Aizen and C.Ezcurra. 1998. High incidence of plant-animal mutualisms in the woody flora of the temperate forest of southern South America: biogeographical origin and present ecological significance. Ecología Austral 8: 217-236.
  • M.T.K.Arroyo, C.Marticorena, P.Miranda, O.Matthei, A.Landero and F.Squeo. 1989. Contribution to the high elevation flora of the Chilean Patagonia: a checklist of species on mountains on an east-west transect in the Sierra de los Baguales, latitude 50º S. Gayana, Bot. 46: 119-149.
  • L.K.Lustig L. K. 1970. Appraisal of research on geomorphology and surface hydrology of desert environments. In W.G. McGinnies, B.J. Goldman, and P. Paylore, editors. Deserts of the world: An appraisal of research into their physical and biological environments. University of Arizona Press, Tucson. ISBN: 0816501815
  • Frederic P.Miller, Agnes F. Vandome, John McBrewster. 2009. Atacama Desert. VDM Publishing. 128 page
  • V.G.Roig V. G. 1991. Desertification and distribution of mammals in the Southern Cone of South America. In M. A. Mares and D. J. Schmidly, Latin American mammology, history, biodiversity and conservation. Norman and London: Univ. Oklahoma Press. ISBN: 0806123435
  • World Wildlife Fund. 2003. Magellanic subpolar forests
Glossary

Citation

Hogan, C. (2013). Ecoregions of Chile . Retrieved from http://www.eoearth.org/view/article/51cbed7b7896bb431f69279f

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