The Gran Chaco or simply Chaco is a sparsely populated, hot and semiarid

lowland Upland and lowland are conditional descriptions of a plain based on elevation above sea level. In studies of the ecology of freshwater rivers, habitats are classified as upland or lowland. Definitions Upland and lowland are portions of a ...

natural region A natural region (landscape unit) is a basic geographic unit. Usually, it is a region which is distinguished by its common natural features of geography, geology, and climate. From the ecological point of view, the naturally occurring flora and ...

of the

Río de la Plata The Río de la Plata (; ), also called the River Plate or La Plata River in English, is the estuary formed by the confluence of the Uruguay River and the Paraná River at Punta Gorda, Colonia, Punta Gorda. It empties into the Atlantic Ocean and ...

basin, divided among eastern

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

, western

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

, northern

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

, and a portion of the Brazilian states of

Mato Grosso Mato Grosso ( – ) is one of the states of Brazil, the List of Brazilian states by area, third largest by area, located in the Central-West Region, Brazil, Central-West region. The state has 1.66% of the Brazilian population and is responsible ...

and

Mato Grosso do Sul Mato Grosso do Sul ( ) is one of Federative units of Brazil, Brazil's 27 federal units, located in the southern part of the Central-West Region, Brazil, Central-West Region, bordering five Brazilian states: Mato Grosso (to the north), Goiás and ...

, where it is connected with the

Pantanal The Pantanal () is a natural region encompassing the world's largest tropical wetland area, and the world's largest Flooded grasslands and savannas, flooded grasslands. It is located mostly within the Brazilian state of Mato Grosso do Sul, but i ...

region. This land is sometimes called the Chaco Plain. The ecoregion has an estimated population of 3,985,000.

Toponymy

The name Chaco comes from the Quechua word meaning "hunting land", an indigenous language from the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

and highlands of South America, and comes probably from the rich variety of animal life present throughout the entire region.

Geography

The Gran Chaco is about 647,500km² (250,000 sq mi) in size, though estimates differ. It is located west of the Paraguay River and east of the

, and is mostly an alluvial sedimentary plain shared among Paraguay, Bolivia, and Argentina. It stretches from about 17 to 33°S latitude and between 65 and 60°W longitude, though estimates differ. Historically, the Chaco has been divided in three main parts: the ''Chaco Austral'' or Southern Chaco, south of the Bermejo River and inside Argentinian territory, blending into the

Pampa The Pampas (; from Quechuan languages, Quechua 'plain'), also known as the Pampas Plain, are fertile South American low grasslands that cover more than and include the Argentina, Argentine Provinces of Argentina, provinces of Buenos Aires Pro ...

region in its southernmost end; the ''Chaco Central'' or Central Chaco between the Bermejo and the Pilcomayo River to the north, also now in Argentinian territory; and the ''Chaco Boreal'' or Northern Chaco, north of the Pilcomayo up to the Brazilian Pantanal, inside Paraguayan territory and sharing some area with Bolivia. Locals sometimes divide it today by the political borders, giving rise to the terms Argentinian Chaco, Paraguayan Chaco, and Bolivian Chaco. (Inside Paraguay, people sometimes use the expression Central Chaco for the area roughly in the middle of the Chaco Boreal, where

Mennonite Mennonites are a group of Anabaptism, Anabaptist Christianity, Christian communities tracing their roots to the epoch of the Radical Reformation. The name ''Mennonites'' is derived from the cleric Menno Simons (1496–1561) of Friesland, part of ...

colonies are established.) The Chaco Boreal may be divided in two: closer to the mountains in the west, the ''Alto Chaco'' (Upper Chaco), sometimes known as ''Chaco Seco'' (or Dry Chaco), is very dry and sparsely vegetated. To the east, less arid conditions combined with favorable soil characteristics permit a seasonally dry higher-growth thorn tree forest, and further east still higher rainfall combined with improperly drained lowland soils result in a somewhat swampy plain called the ''Bajo Chaco'' (Lower Chaco), sometimes known as ''Chaco Húmedo'' ( Humid Chaco). It has a more open

savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach th ...

vegetation consisting of palm trees, quebracho trees, and tropical high-grass areas, with a wealth of

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s. The landscape is mostly flat and slopes at a 0.004-degree gradient to the east. This area is also one of the distinct physiographic provinces of the Parana-Paraguay Plain division. The areas more hospitable to development are along the

, Bermejo, and Pilcomayo Rivers. It is a great source of

timber Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). ...

and

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and Precipitation (chemistry), precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' is widel ...

, which is derived from the native ''quebracho'' tree. Special tannin factories have been constructed there. The wood of the palo santo from the Central Chaco is the source of oil of guaiac (a fragrance for

soap Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...

). Paraguay also cultivates mate in the lower part of the Chaco. Large tracts of the central and northern Chaco have high

soil fertility Soil fertility refers to the ability of soil to sustain agricultural plant growth, i.e. to provide plant habitat and result in sustained and consistent yields of high quality.

, sandy alluvial soils with elevated levels of

phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...

, and a topography that is favorable for agricultural development. Other aspects are challenging for farming: a semiarid to semihumid climate (600–1300mm annual rainfall) with a six-month dry season and sufficient fresh groundwater restricted to roughly one-third of the region, two-thirds being without groundwater or with groundwater of high salinity. Soils are generally erosion-prone once the forest has been cleared. In the central and northern Paraguay Chaco, occasional dust storms have caused major topsoil loss.

History

The Chaco was occupied by nomadic peoples, notably the various groups making up the Guaycuru, who resisted Spanish control of the Chaco, often with success, from the 16th until the early 20th centuries. Prior to national independence of the nations that compose the Chaco, the entire area was a separate colonial region named by the Spaniards as ''Chiquitos''. The Gran Chaco had been a disputed territory since 1810. Officially, it was supposed to be part of Argentina, Bolivia, and Paraguay, although a bigger land portion west of the Paraguay River had belonged to Paraguay since its independence. Argentina claimed territories north of the Bermejo River until Paraguay's defeat in the War of the Triple Alliance in 1870 established its current border with Argentina. Over the next few decades, Bolivia began to push the natives out and settle in the Gran Chaco, while Paraguay ignored it. Bolivia sought the Paraguay River for shipping oil out into the sea (it had become a land-locked country after the loss of its Pacific coast in the

War of the Pacific The War of the Pacific (), also known by War of the Pacific#Etymology, multiple other names, was a war between Chile and a Treaty of Defensive Alliance (Bolivia–Peru), Bolivian–Peruvian alliance from 1879 to 1884. Fought over Atacama Desert ...

), and Paraguay claimed ownership of the land. This became the backdrop to the Gran Chaco War (1932–1935) between Paraguay and Bolivia over supposed oil in the Chaco Boreal (the aforementioned region north of the Pilcomayo River and to the west of the Paraguay River). Eventually, Argentine Foreign Minister

Carlos Saavedra Lamas Carlos Saavedra Lamas (November 1, 1878 – May 5, 1959) was an Argentine academic and politician, and in 1936, the first Latin American Nobel Peace Prize recipient. Biography Born in Buenos Aires, Saavedra Lamas was a descendant of an early Ar ...

mediated a ceasefire and subsequent treaty signed in 1938, which gave Paraguay three-quarters of the Chaco Boreal and gave Bolivia a corridor to the Paraguay River with the ability to use the Puerto Casado and the right to construct their own port. No oil was found in the region until 2012 when Paraguayan President Federico Franco announced the discovery of oil in the area of the Pirity river.

s immigrated into the Paraguayan part of the region from Canada in the 1920s; more came from the

USSR The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

in the 1930s and immediately following World War II. These immigrants created some of the largest and most prosperous municipalities in the deep Gran Chaco. The region is home to over 9 million people, divided about evenly among Argentina, Bolivia, and Brazil, and including around 100,000 in Paraguay. The area remains relatively underdeveloped, In the 1960s, the Paraguayan authorities constructed the Trans-Chaco Highway and the Argentine National Highway Directorate, National Routes 16 and 81, in an effort to encourage access and development. All three highways extend about from east to west and are now completely paved, as is a network of nine Brazilian highways in Mato Grosso do Sul state.

Flora

The Gran Chaco has some of the highest temperatures on the continent. It has high

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

, containing around 3,400 plant species, 500 birds, 150 mammals, and 220 reptiles and amphibians. The floral characteristics of the Gran Chaco are varied given the large geographical span of the region. The dominant vegetative structure is xerophytic deciduous forests with multiple layers, including a canopy (trees), subcanopy, shrub layer, and herbaceous layer. Ecosystems include riverine forests,

wetlands A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

savannas A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that the Canopy (forest), canopy does not close. The open canopy allows sufficient li ...

, and cactus stands, as well. At higher elevations of the eastern zone of the Humid Chaco, mature forests transition from the wet forests of southern Brazil. These woodlands are dominated by canopy trees such as '' Handroanthus impetiginosus'' and characterized by frequent lianas and

epiphytes An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

. This declines to seasonally flooded forests, at lower elevations, that are dominated by '' Schinopsis'' spp., a common plains tree genus often harvested for its

content and dense wood. The understory comprises bromeliad and cactus species, as well as hardy shrubs such as '' Schinus fasciculata''. These lower areas lack lianas, but have abundant epiphytic species such as ''

Tillandsia ''Tillandsia'' is a genus of around 650 species of evergreen, perennial plant, perennial flowering plants in the family (biology), family Bromeliaceae, native to the forests, mountains and deserts of the Neotropical realm, Neotropics, from northe ...

''. The river systems that flow through the area, such as the Rio Paraguay and Rio Parana, allow for seasonally flooded semievergreen gallery forests that hold riparian species such as '' Tessaria integrifolia'' and '' Salix humboldtiana''. Other seasonally flooded ecosystems of this area include palm-dominated ('' Copernicia alba'') savannas with a bunch grass-dominated herbaceous layer. To the west, in the Semiarid/Arid Chaco, medium-sized forests consists of white quebracho ('' Aspidosperma quebracho-blanco'') and red quebracho ('' Schinopsis lorentzii'') with a slightly shorter subcanopy made up of several species from the family Fabaceae, as well as several arboreal cacti species that distinguish this area of the Chaco. There is a scrub-like shrub and herbaceous understory. On sandy soils, the thick woodlands turn into savannas where the aforementioned species prevail, as well as species such as ''

Jacaranda mimosifolia ''Jacaranda mimosifolia'' is a sub-tropical tree native to south-central South America that has been widely planted elsewhere because of its attractive and long-lasting Violet (color), violet-colored flowers. It is also known as the jacaranda, b ...

''. The giant '' Stetsonia coryne'', found throughout the western Semiarid/Arid region becomes very conspicuous in these sandy savannas. Various upland systems of plant associations occur throughout the Gran Chaco. The Highlands of the Argentinian Chaco are made up of, on the dry, sunny side (up to 1800m), '' Schinopsis haenkeana'' woodlands. The cooler side of the uplands hosts '' Zanthoxylum coco'' (locally referred to as Fagara coco) and '' Schinus molleoides'' (locally referred to as '' Lithrea molleoides'') as the predominant species. Other notable species include '' Bougainvillea stipitata'', and several species from the Fabaceae. The Paraguayan uplands have other woodland slope ecosystems, notably, those dominated by ''

Anadenanthera colubrina ''Anadenanthera colubrina'' (also known as vilca, huilco, huilca, wilco, willka, curupay, curupau, cebil, or angico) is a South American tree closely related to yopo, or ''Anadenanthera peregrina''. It grows to tall and the trunk is very thorn ...

'' on moist slopes. Both of these upland systems, as well as numerous other Gran Chaco areas, are rich with

endemism Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Fauna

Faunal diversity in the Gran Chaco is also high. The Gran Chaco has around 3,400 plant, 500 bird, 150 mammal, and 220 reptile and amphibian species. Animals typically associated with tropical and subtropical forests are often found throughout the eastern Humid Chaco, including jaguars, howler monkeys, peccaries, deer, and tapirs. ''

Edentate Xenarthra (; from Ancient Greek wikt:ξένος, ξένος, xénos, "foreign, alien" + wikt:ἄρθρον, ἄρθρον, árthron, "joint") is a Order (biology), superorder and major clade of Placentalia, placental mammals native to the America ...

'' species, including anteaters and armadillos, are readily seen here, as well.Napamalo: The Giant Anteater of the Gran Chaco, 2003. Being home to at least 10 species, the Argentinian Chaco is the location of the peak diversity for the armadillo, including species such as the

nine-banded armadillo The nine-banded armadillo (''Dasypus novemcinctus''), also called the nine-banded long-nosed armadillo or common long-nosed armadillo, is a species of armadillo native to North America, North, Central America, Central, and South America, making ...

(''Dasypus novemcinctus''), whose range extends north to the southern US, and the southern three-banded armadillo (''Tolypeutes matacus'').Conservation ecology of armadillos in the Chaco region of Argentina, 1: 16–17, Edentata, 1994. The pink fairy armadillo (''Chlamyphrous truncatus''), is found nowhere else in the world.Guiá de los Mamiferos Argentinos, 19840. The giant armadillo (''Priodontes maximus''), while not found in the eastern Humid Chaco, can be seen in the drier Arid Chaco of the west. Some other notable endemics of the region include the San Luis tuco-tuco (''Ctenomys pontifex''). This small rodent is only found in the Argentinian Chaco. All of 60 species of '' Ctenomys'' are endemic to South America. The Chacoan peccary (''Catagonus wagneri''), locally known as ''tauga'', is the largest of the three peccary species found in the area. This species was thought to be extinct by scientists until 1975, when it was recorded by Ralph Wetzel.Catagonous, an "extinct" peccary, alive in Paraguay, 189:379–381, Science, 1975. Due to the climate of the Gran Chaco, herpetofauna are restricted to moist refugia in various places throughout the chaco. Rotting logs, debris piles, old housing settlement, wells, and seasonal farm ponds are examples of such refugia.Ecological Notes on the Paraguayan Chaco Herpetofauna, 12(3), 433–435, Journal of Herpetology, 1978. The black-legged seriema (''Chunga burmeisteri''), blue-crowned parakeet (''Aratinga acuticadauta''), Picui ground dove (''Columbina picui''), guira cuckoo (''Guira guira''), little thornbird (''Phacellodomus sibilatrix''), and many-colored Chaco finch (''Saltaitricula multicolor'') are notable of the 409 bird species that are resident or breed in the Gran Chaco; 252 of these Chaco species are endemic to South America."A Zoogeographic Analysis Of The South American Chaco Avifauna", 154(3), 165–352, ''Bulletin of the American Museum of Natural History'', 1975.

Conservation issues

The Chaco is one of South America's last agricultural frontiers. Very sparsely populated and lacking sufficient all-weather roads and basic infrastructure (the Argentinian part is more developed than the Paraguayan or Bolivian part), it has long been too remote for crop planting. The central Chaco's Mennonite colonies are a notable exception. Between 2000 and 2019, it was estimated that the Dry Chaco forest cover decreased by 20.2%, including territory in Argentina, Bolivia, and Paraguay, with the latter showing the most dramatic land cover change. Two factors may substantially change the Chaco in the near future: low land valuations and the region's suitability to grow fuel crops. Suitability for the cultivation of '' Jatropha'' has been proven. Sweet sorghum as an ethanol plant may prove viable, too, since sorghum is a traditional local crop for domestic and feedstock use. The feasibility of

switchgrass ''Panicum virgatum'', commonly known as switchgrass, is a perennial warm season bunchgrass native to North America, where it occurs naturally from 55th parallel north, 55°N latitude in Canada southwards into the United States and Mexico. Switch ...

is currently being studied by Argentina's Instituto Nacional de Tecnología Agropecuaria, as is the Karanda'y palm tree in the Paraguayan Chaco. While advancements in agriculture can bring some improvements in infrastructure and employment for the region, loss of habitat and virgin forest is substantial and will likely increase

poverty Poverty is a state or condition in which an individual lacks the financial resources and essentials for a basic standard of living. Poverty can have diverse Biophysical environmen ...

. Paraguay, after having lost more than 90% of its Atlantic rainforest between 1975 and 2005, is now losing its xerophytic forest (dry forests) in the Chaco at an annual rate of (2008). In mid-2009, a projected law, initiated by the

Liberal Party The Liberal Party is any of many political parties around the world. The meaning of ''liberal'' varies around the world, ranging from liberal conservatism on the right to social liberalism on the left. For example, while the political systems ...

, that would have outlawed

deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...

in the Paraguayan Chaco altogether, "Deforestacion Zero en el Chaco" did not get a majority in the parliament. Deforestation in the Argentinian part of the Chaco amounted to an average of per year between 2001 and 2007. According to Fundación Avina, a local NGO, on average, are cleared per day. The soy plantations not only eliminate the forest, but also other types of agriculture. Indigenous communities are losing their land to agribusinesses. Since 2007, a law is supposed to regulate and control the cutting of timber in the Gran Chaco, but

illegal logging Illegal logging is the harvest, transportation, purchase, or sale of timber in violation of laws. The harvesting procedure itself may be illegal, including using corrupt means to gain access to forests; extraction without permission, or from a p ...

continues. Among the aggressive investors in the Paraguayan Gran Chaco are U.S.-based agribusinesses Cargill Inc., Bunge Ltd., and

Archer Daniels Midland The Archer-Daniels-Midland Company, commonly known as ADM, is an American multinational food processing and commodities trading corporation founded in 1902 and headquartered in Chicago, Chicago, Illinois. The company operates more than 270 p ...

Co.

Protected areas

A 2017 assessment found that 176,715km², or 22%, of the ecoregion is in protected areas. In September 1995, the Kaa-Iya del Gran Chaco National Park and Integrated Management Natural Area was established in an area of the Chaco in Bolivia. It is administered and was established solely by the

indigenous peoples There is no generally accepted definition of Indigenous peoples, although in the 21st century the focus has been on self-identification, cultural difference from other groups in a state, a special relationship with their traditional territ ...

, including the Izoceño Guaraní, the Ayoreode, and the Chiquitano. Other protected areas include Defensores del Chaco National Park and Tinfunqué National Park in Paraguay, and Copo National Park and El Impenetrable National Park in Argentina.

Administrative divisions in the Gran Chaco

The following Argentine provinces, Bolivian and Paraguayan departments, and Brazilian states lie in the Gran Chaco area, either entirely or in part.

Indigenous peoples

* Abipón, Argentina, historic group * Angaite (Angate), northwestern Paraguay * Ayoreo"Cultural Thesaurus."
''National Museum of the American Indian.'' (retrieved 18 February 2011) (Morotoco, Moro, Zamuco), Bolivia and Paraguay * Chamacoco ( Zamuko), Paraguay * Chané, Argentina and Bolivia * Chiquitano (Chiquito, Tarapecosi), eastern Bolivia * Chorote ( Choroti), Iyojwa'ja Chorote, Manjuy), Argentina, Bolivia, and Paraguay * Guana (Kaskihá), Paraguay * Guaraní, Argentina, Bolivia, Brazil, and Paraguay ** Bolivian Guarani *** Eastern Guarani (Chiriguano), Bolivia *** Guarayo (East Bolivian Guarani) ** Chiripá (Tsiripá, Ava), Bolivia ** Pai Tavytera (Pai, Montese, Ava), Bolivia ** Tapieté ( Guaraní Ñandéva, Yanaigua), eastern Bolivia ** Yuqui (Bia), Bolivia * Guaycuru peoples, Argentina, Bolivia, Brazil, and Paraguay ** Mbayá (Caduveo), historic *** Kadiweu, Brazil ** Mocoví (Mocobí), Argentina ** Payaguá **

Pilagá fThe Pilagá (in Pilagá language, Pilagá language: ''pit'laxá'') are an Indigenous peoples of the Americas, indigenous people of the Guaycuru peoples, Guaycuru group that inhabits the center of the province of Formosa Province, Formosa, in Arge ...

(Pilage Toba) ** Toba (Qom, Frentones), Argentina, Bolivia, and Paraguay * Kaiwá, Argentina and Brazil * Lengua people ( Enxet), Paraguay ** North Lengua ( Eenthlit, Enlhet, Maskoy), Paraguay ** South Lengua, Paraguay * Lulé (Pelé, Tonocoté), Argentina * Maká (Towolhi), Paraguay * Nivaclé ( Ashlushlay, Chulupí, Chulupe, Guentusé), Argentina, and Paraguay * Sanapaná (Quiativis), Paraguay * Vilela, Argentina * Wichí (Mataco), Argentina and Bolivia Many of these peoples speak or used to speak Mataco–Guaicuru languages.

References

External links

* * ttp://www.ventacamposparaguay.com/photos.htm photosof the Paraguay Chaco {{Authority control La Plata basin Natural regions of South America Regions of Argentina Regions of Bolivia Regions of Paraguay Ecoregions of South America Ecoregions of Argentina Ecoregions of Bolivia Ecoregions of Brazil Ecoregions of Paraguay Grasslands of Argentina Grasslands of Bolivia Grasslands of Brazil Grasslands of Paraguay Grasslands of South America Geography of Argentina Geography of Bolivia Geography of Mato Grosso Geography of Mato Grosso do Sul Geography of Paraguay Environment of Mato Grosso Environment of Mato Grosso do Sul Quechua words and phrases Physiographic provinces Neotropical dry broadleaf forests Tropical and subtropical dry broadleaf forests