The Gran Chaco or Dry Chaco is a sparsely populated, hot and semi-arid lowland natural region of the Río de la Plata basin, divided among eastern Bolivia, western Paraguay, northern Argentina and a portion of the Brazilian states of Mato Grosso and Mato Grosso do Sul, where it is connected with the Pantanal region. This land is sometimes called the Chaco Plain.
Dry Chaco (NT0210)
Landscape in the Gran Chaco,
Chaco Boreal, Paraguay
Dry Chaco as delimited by WWF: World Wildlife Fund
|Countries||Paraguay, Bolivia, Argentina and Brazil|
|Elevation||310 m (1,020 ft)|
The name Chaco comes from a word in Quechua, an indigenous language from the Andes and highlands of South America. The quechua word chaqu meaning "hunting land" comes probably from the rich variety of animal life present throughout the entire region.
The Gran Chaco is about 647,500 km² (250,000 sq mi) in size, though estimates differ. It is located west of the Paraguay River and east of the Andes, and is mostly an alluvial sedimentary plain shared among Paraguay, Bolivia and Argentina. It stretches from about 17° to 33° South latitude and between 65° and 60° West 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 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 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 vegetation consisting of palm trees, quebracho trees and tropical high-grass areas, with a wealth of insects. 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 Paraguay, Bermejo and Pilcomayo Rivers. It is a great source of timber and tannin, 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). Paraguay also cultivates mate in the lower part of the Chaco.
Large tracts of the central and northern Chaco have high soil fertility, sandy alluvial soils with elevated levels of phosphorus and a topography that is favorable for agricultural development. Other aspects are challenging for farming: a semi-arid to semi-humid climate (600–1300 mm 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 top soil loss.
The Chaco was occupied by nomadic peoples, notably the various groups making up the Guaycuru who resisted Spanish control, often with success, of the Chaco from the 16th until the early 20th century.
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 south 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), 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 mediated a cease fire 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. In the end, no oil was found in the region.
Mennonites immigrated into the Paraguayan part of the region from Canada in the 1920s; more came from the USSR 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 nine million people, divided about evenly among Argentina, Bolivia, 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 700 km (430 mi) from east to west and are now completely paved, as are a network of nine Brazilian highways in Mato Grosso do Sul State.
The Gran Chaco has some of the highest temperatures on the continent.
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), sub-canopy, shrub layer and herbaceous layer. There are ecosystems such as riverine forests, wetlands, savannas, and cactus stands as well.
At higher elevations of the eastern zone of the Humid/Sub-humid Chaco there are transitional mature forests 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. This declines to seasonally flooded forests, at lower elevations, that are dominated by Schinopsis spp., a common plains tree genus often harvested for its tannin content and dense wood. The understory comprises bromeliad and cactus species as well as hardy shrubs like Schinus fasciculatus. These lower areas lack lianas but have abundant epiphytic species like Tillandsia. The river systems that flow through the area, such as the Rio Paraguay and Rio Parana allow for seasonally flooded semi evergreen gallery forests that hold riparian species such as Tessaria integrifolia and Salix humboltiana. 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 Semi-Arid/Arid Chaco, there are medium-sized forests consisting of Aspidosperma quebracho-blanco and Schinopsis quebracho with a slightly shorter subcanopy made up of several species from the Fabaceae family as well as several arboreal cacti species that distinguish this area of the Chaco. There is a scrub-like shrub and herbaceous layer. On sandy soils, the thick woodlands turn into savannas where the aforementioned species prevail as well as species like Jacaranda mimosifolia. The giant Stetsonia coryne, found throughout the western Semi-Arid/Arid region becomes very conspicuous in these sandy savannas. There are various upland systems of plant associations that 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 spp. from Fabaceae. The Paraguyan uplands have other woodland slope ecosystems, notably, those dominated by Anadenanthera colubrina on moist slopes. Both of these upland systems, as well as numerous other Gran Chaco areas, are rich with endemism.
Faunal diversity in the Gran Chaco is high as well.The Gran Chaco has high levels of biodiversity, containing around 3,400 plant species, 500 birds, 150 mammals and 220 reptiles and amphibians. 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 species, including anteaters and armadillos, are readily seen here as well. Being home to at least ten species, the Argentinian Chaco is the location of the peak diversity for the armadillo, including species such as the nine-banded armadillo (Dasypus novemcinctus) whose range extends north to the southern US, and the southern three-banded armadillo (Tolypeutes matacus). The pink fairy armadillo (Chlamyphrous truncatus), is found nowhere else in the world. 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 the continent of 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 Dr. Ralph Wetzel.
Due to the climatic regime 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. 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.
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, including the Izoceño Guaraní, the Ayoreode, and the Chiquitano.
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.
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 is currently being studied by Argentina's INTA, 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 / virgin forest is substantial and will likely increase poverty. 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 220,000 hectares (540,000 acres) (2008) In mid-2009 a projected law, initiated by the Liberal Party, that would have outlawed deforestation 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 100,000 hectares (250,000 acres) per year between 2001 and 2007  According to Fundación Avina, a local NGO, on average, 1130 hectares are cut down per day – this equals 2300 football fields. The soy plantations not only eliminate the forest, but also other types of agriculture as well. Indigenous communities are losing their land to agrobusinesses. Since 2007, there is a law which is supposed to regulate and control the cutting of timber in the Gran Chaco, but illegal logging continues.
The following Argentine provinces, Bolivian and Paraguayan departments and Brazilian states lie in the Gran Chaco area, either entirely or in part.
|Santa Fe Province|
|Santiago del Estero Province|
|Santa Cruz Department|
|Alto Paraguay Department,||Paraguay|
|Presidente Hayes Department|
|State of Mato Grosso do Sul||Brazil|
alluvial sandy soils have P (phosphorus) levels of up to 200–300 ppm
The Gran Chaco was one of the last frontiers in South America – but agricultural development, largely driven by soy, is gathering pace.
The Abipones (Spanish: Abipones, singular Abipón) were an indigenous peoples of Argentina's Gran Chaco, speakers of one of the Guaicuruan languages. They ceased to exist as an independent ethnic group in the early 19th century. A small number of survivors assimilated into Argentine society.Chaco War
The Chaco War (1932–1935; Spanish: Guerra del Chaco, Guarani: Cháko Ñorairõ) was fought between Bolivia and Paraguay over control of the northern part of the Gran Chaco region (known in Spanish as Chaco Boreal) of South America, which was thought to be rich in oil. It is also referred to as La Guerra de la Sed (Spanish for "The War of Thirst") in literary circles, for being fought in the semi-arid Chaco. It was the bloodiest military conflict fought in South America during the 20th century, between two of its poorest countries, both having previously lost territory to neighbors in 19th-century wars.
During the war, both landlocked countries faced difficulties shipping arms and supplies through neighboring countries. Bolivia faced particular external trade problems, coupled with poor internal communications. Although Bolivia had lucrative mining income and a larger, better-equipped army, a series of factors turned the tide against it, and Paraguay came to control most of the disputed zone by war's end.
The ultimate peace treaties granted two-thirds of the disputed territories to Paraguay.Chaco eagle
The Chaco eagle, or crowned solitary eagle (Buteogallus coronatus), is an endangered bird of prey from eastern and central South America. Typically it is known simply as the crowned eagle which leads to potential confusion with the African Stephanoaetus coronatus. The Chaco eagle is a large raptor with a length of 73–79 cm (28.5–31 in), a wingspan of 170–183 cm (67–72 in) and an average weight of 2.95 kg (6.5 lb). Adults are almost entirely gray with a large occipital crest and a short, black-and-white-banded tail. The juvenile is gray-brown on the back and pale with gray-brown streaks on the head and underside.Chacoan gracile opossum
The chacoan gracile opossum (Cryptonanus chacoensis) is a species of opossum in the family Didelphidae. It is native to Argentina, Brazil and Paraguay. Its habitat is seasonally flooded grasslands and forests in and near the Gran Chaco.Chacoan peccary
The Chacoan peccary or tagua (Catagonus wagneri) is the last extant species of the genus Catagonus; it is a peccary found in the Gran Chaco of Paraguay, Bolivia, and Argentina. Approximately 3,000 remain in the world. It is believed to be the closest living relative to the extinct genus Platygonus.
The Chacoan peccary has the unusual distinction of having been first described in 1930 based on fossils and was originally thought to be an extinct species. In 1971, the animal was discovered to still be alive in the Chaco region, in the Argentine province of Salta. The species was well known to the native people, but it took a while for scientists to acknowledge its existence. It is known locally as the tagua.Chamacoco
The Chamacoco people (Ishír) are an indigenous people of Paraguay. Some also live in Brazil.The Chamacoco have two major divisions, the Ebytoso, who lived along the Paraguay River, and the Tomáraho, who traditionally lived in the forests. The Ebytoso converted to Christianity, while the Tomáraho have lived in marginal areas in order to preserve their traditional world views and lifeways. In the 1980s the Instituto Nacional del Indigena (INDI) resettled the Tomáraho in a community called Puerto Esperanza with the Ebytoso.Chané
Chané is the collective name for the southernmost Arawak-speaking peoples. They lived in the plains of the northern Gran Chaco and in the foothills of the Andes in Paraguay, Brazil, Bolivia, and Argentina. The historical Chané are divided into two principal groups. The Chané proper who lived in eastern Bolivia and the Guaná who lived in Paraguay and adjacent Brazil. Twenty-first century survivors of the Chané are the Izoceno people of Bolivia and 3,034 descendants reported in Argentina by the 2010 census. Survivors of the Guaná are the Tereno and the Kinikinao both of Mato Grosso do Sul province in Brazil.Most of the historical Chané were subjects of and absorbed by the Eastern Bolivian Guarani, commonly called Chiriguanos, while the Guaná were subjects of the Mbayá, a Guaycuruan speaking people.Cordillera Province (Bolivia)
Cordillera is a province in the Santa Cruz Department, Bolivia. Its capital is Lagunillas.Enxet
The Enxet are an indigenous people of about 17,000 living in the Gran Chaco region of western Paraguay. Originally hunter-gatherers, many are now forced to supplement their livelihood as laborers on the cattle ranches that have encroached upon their dwindling natural forest habitat. Nevertheless, the Enxet are still engaged in an ongoing conflict with the government and ranchers, who want to destroy what remains of the forest to open the land for massive settlement. Today, only a handful of Enxet are still able to maintain their traditional way of life, while the majority live in small settlements sponsored by various missionary organizations. The Enxet language is still vigorous.Erke
The erke (alternatively erque, coroneta, or quepa) is a large labrophone (lip reed) instrument native to the Gran Chaco of Bolivia, northern Chile, and Argentine Northwest.Gran Chaco Province
Gran Chaco is a province in the eastern parts of the Bolivian department Tarija. The province voted to become an autonomous region on 6 December 2009.Gran Chaco people
The indigenous Gran Chaco people consist of approximately thirty-five tribal groups in the Gran Chaco of South America. Because, like the Great Plains of North America, the terrain lent itself to a nomadic lifestyle, there is little to no archaeological evidence of their prehistoric occupation. Contributing to this near-absence of archaeological data is the lack of suitable raw material for stone tools or permanent construction and soil conditions that are not conducive to the preservation of organic material.Guaraní War
The Guarani War (Spanish: Guerra Guaranítica, Portuguese: Guerra Guaranítica) of 1756, also called the War of the Seven Reductions, took place between the Guaraní tribes of seven Jesuit Reductions and joint Spanish-Portuguese forces. It was a result of the 1750 Treaty of Madrid, which set a line of demarcation between Spanish and Portuguese colonial territory in South America.
The boundary drawn up between the two nations was the Uruguay River, with Portugal possessing the land east of the river. The seven Jesuit missions east of the Uruguay River, known as the Misiones Orientales, were to be dismantled and relocated on the Spanish western side of the river. The seven missions were called San Miguel, Santo Ángel, San Lorenzo Martir, San Nicolás, San Juan Bautista, San Luis Gonzaga, and San Francisco de Borja. These missions were some of the most populous in South America with 26,362 inhabitants, according to a Jesuit census, and many more in the surrounding areas.In 1754 the Jesuits surrendered control of the missions, but the Guaraní led by Sepé Tiaraju, refused to comply with the order to relocate. Efforts by the Spanish army in 1754 to forcefully remove the Guarani from the missions failed. On February 10, 1756, a combined force of 3,000 Spanish and Portuguese soldiers fought the Guaraní at the battle of Caiboaté. It resulted in the death of 1,511 Guaraní, while the Europeans suffered only 4 deaths. In the aftermath of the battle, the joint Spanish-Portuguese army occupied the seven missions.
Eventually Spain and Portugal annulled the 1750 treaty in the Treaty of El Pardo (1761), with Spain regaining control over the seven missions and its surrounding territory.Indigenous peoples in Bolivia
Indigenous peoples in Bolivia, or Native Bolivians, are Bolivian people who are of indigenous ancestry. They constitute approximately 20% of Bolivia's population of 2,261,269 and belong to 36 recognized ethnic groups. Aymara and Quechua are the largest groups. The geography of Bolivia includes the Andes, the Gran Chaco, and the Amazon Rainforest.
Indigenous Bolivians are a large ethnic group in Bolivia, accounting for 20% of the country's population. An additional 68% of the population is mestizo, having mixed European and indigenous ancestry.Indigenous peoples in Paraguay
Indigenous peoples in Paraguay, or Native Paraguayans, include 17 ethnic groups belonging to five language families. While only a 1.7% of Paraguay's population is fully indigenous, 95% of the population identifies as being partially of indigenous; however, the majority do not identify as being indigenous but as Mestizos. Most of the Indian population lives in the northwestern part of the country, the Gran Chaco.Kaa-Iya del Gran Chaco National Park and Integrated Management Natural Area
Kaa-Iya del Gran Chaco National Park and Integrated Management Natural Area (Parque Nacional y Area Natural de Manejo Integrado Kaa-Iya del Gran Chaco) is the biggest national park in Bolivia and one of the largest in South America. It is a protected area in the region of the Gran Chaco and has a larger surface area than Belgium. It is situated in the south of Santa Cruz Department on the border with Paraguay in the Cordillera Province (Charagua Municipality) and Chiquitos Province (Pailón Municipality and San José de Chiquitos Municipality).Mocoví
The Mocoví are an indigenous tribe of the Gran Chaco. They speak the Mocoví language and are one of the ethic groups belonging to the Guaycuru peoples.Nivaclé
The Nivaclé are an indigenous people of the Gran Chaco. An estimated 13,700 Nivaclé people live in the President Hayes and Boquerón Departments in Paraguay, while approximately 200 Nivaclé people live in the Salta Province of Argentina. A very small number of Nivaclé live in Tarija, Bolivia.
In the last 50 years, 15,000 Mennonites from Canada, Russia, and Germany have settled in traditional Nivaclé territory.Oligoryzomys chacoensis
Oligoryzomys chacoensis, also known as the Chacoan colilargo or Chacoan pygmy rice rat, is a rodent species from South America. It is found in the Gran Chaco region of southeastern Bolivia, southwestern Brazil, Paraguay, and northeastern Argentina. Its karyotype has 2n = 58 and FNa = 74.It is one of the hosts of the hantavirus serotype Bermejo.