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Gran Chaco

Coordinates:19°09′44″S61°28′13″W/ 19.1622°S 61.4702°W/-19.1622; -61.4702
From Wikipedia, the free encyclopedia
For the Bolivian province, seeGran Chaco Province.For the Argentine province, seeChaco Province.For the region of Paraguay, seeChaco (Paraguay).
Gran Chaco
Dry Chaco
Landscape in the Gran Chaco,
Chaco Boreal, Paraguay
Dry Chaco as delimited by theWorld Wildlife Fund
Ecology
RealmNeotropical
Biometropical and subtropical dry broadleaf forests
Borders
List
Geography
Area786,791 km2(303,782 sq mi)
Countries
Conservation
Protected176,715 km2(22%)[1]

TheGran ChacoorDry Chacois a sparsely populated, hot and semiaridlowlandtropical dry broadleaf forestnatural regionof theRío de la Platabasin, divided among easternBolivia,westernParaguay,northernArgentina,and a portion of the Brazilian states ofMato GrossoandMato Grosso do Sul,where it is connected with thePantanalregion. This land is sometimes called theChaco Plain.

Toponymy[edit]

The name Chaco comes from a word inQuechua,an indigenous language from theAndesand highlands of South America. The Quechua wordchaqumeaning "hunting land" comes probably from the rich variety of animal life present throughout the entire region.

Geography[edit]

A bulldozer clearing native forest in the Chaco Boreal and environmentalists campaigning against it
Alto Chaco, virgin forest in dry season
Bajo Chaco, extensive cattle ranching
Deforestation for cattle farming in the Paraguayan part of the Chaco
Regions of Argentina

The Gran Chaco is about 647,500 km2(250,000 sq mi) in size, though estimates differ. It is located west of theParaguay Riverand east of theAndes,and is mostly an alluvial sedimentary plain shared among Paraguay, Bolivia, and Argentina. It stretches from about17to33°Slatitude and between65and60°Wlongitude, though estimates differ.

Historically, the Chaco has been divided in three main parts: theChaco Australor Southern Chaco, south of theBermejo Riverand inside Argentinian territory, blending into thePamparegion in its southernmost end; theChaco Centralor Central Chaco between the Bermejo and thePilcomayo Riverto the north, also now in Argentinian territory; and theChaco Borealor 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, whereMennonitecolonies are established.)

The Chaco Boreal may be divided in two: closer to the mountains in the west, theAlto Chaco(Upper Chaco), sometimes known asChaco 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 theBajo Chaco(Lower Chaco), sometimes known asChaco Húmedo(Humid Chaco). It has a more opensavannavegetation consisting of palm trees,quebracho trees,and tropical high-grass areas, with a wealth ofinsects.The landscape is mostly flat and slopes at a 0.004-degree gradient to the east. This area is also one of the distinctphysiographicprovinces of the Parana-Paraguay Plain division.

The areas more hospitable to development are along theParaguay,Bermejo,andPilcomayo Rivers.It is a great source oftimberandtannin,which is derived from the nativequebrachotree. Special tannin factories have been constructed there. The wood of thepalo santofrom the Central Chaco is the source ofoil of guaiac(a fragrance forsoap). Paraguay also cultivatesmatein the lower part of the Chaco.

Large tracts of the central and northern Chaco have highsoil fertility,sandy alluvial soils with elevated levels ofphosphorus,[2]and a topography that is favorable for agricultural development. Other aspects are challenging for farming: a semiarid to semihumid 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 topsoil loss.

History[edit]

The Chaco was occupied by nomadic peoples, notably the various groups making up theGuaycuru,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 asChiquitos.

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 theWar of the Triple Alliancein 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 theWar of the Pacific), and Paraguay claimed ownership of the land. This became the backdrop tothe 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 MinisterCarlos Saavedra Lamasmediated 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 PresidentFederico Francoannounced the discovery of oil in the area of the Pirity river.[3]

Road construction in the deep Gran Chaco during the 1960s

Mennonitesimmigrated into the Paraguayan part of the region from Canada in the 1920s; more came from theUSSRin 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 theTrans-Chaco Highwayand 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 is a network of nine Brazilian highways in Mato Grosso do Sul state.

Flora[edit]

AnAlgarrobo,white carob tree, in the Gran Chaco area of Argentina. This prized shade tree is common to the area.

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

It has highbiodiversity,containing around 3,400 plant species, 500 birds, 150 mammals, and 220 reptiles and amphibians.[4]

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 acanopy (trees),subcanopy,shrub layer,andherbaceous layer.Ecosystems includeriverine forests,wetlands,savannas,and cactus stands, as well.[5]

At higher elevations of the eastern zone of theHumid Chaco,mature forests transition from the wet forests of southern Brazil. These woodlands are dominated by canopy trees such asHandroanthus impetiginosusand characterized by frequentlianasandepiphytes.This declines to seasonally flooded forests, at lower elevations, that are dominated bySchinopsisspp., a common plains tree genus often harvested for itstannincontent and dense wood. The understory comprises bromeliad and cactus species, as well as hardy shrubs such asSchinus fasciculata.These lower areas lack lianas, but have abundant epiphytic species such asTillandsia.The river systems that flow through the area, such as theRio ParaguayandRio Parana,allow for seasonally flooded semievergreengallery foreststhat hold riparian species such asTessaria integrifoliaandSalix humboldtiana.Other seasonally flooded ecosystems of this area include palm-dominated (Copernicia alba) savannas with abunch 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 asJacaranda mimosifolia.The giantStetsonia 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 haenkeanawoodlands. The cooler side of the uplands hostsZanthoxylum coco(locally referred to asFagara coco) andSchinus molleoides(locally referred to asLithrea molleoides) as the predominant species. Other notable species includeBougainvillea stipitata,and several species from the Fabaceae. The Paraguayan uplands have other woodland slope ecosystems, notably, those dominated byAnadenanthera colubrinaon moist slopes.[5]Both of these upland systems, as well as numerous other Gran Chaco areas, are rich withendemism.

Fauna[edit]

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.Edentatespecies, including anteaters and armadillos, are readily seen here, as well.[6]Being home to at least 10 species, the Argentinian Chaco is the location of the peak diversity for the armadillo, including species such as thenine-banded armadillo(Dasypus novemcinctus), whose range extends north to the southern US, and thesouthern three-banded armadillo(Tolypeutes matacus).[7]Thepink fairy armadillo(Chlamyphrous truncatus), is found nowhere else in the world.[8]Thegiant 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 theSan Luis tuco-tuco(Ctenomys pontifex).[6]This small rodent is only found in the Argentinian Chaco. All of 60 species ofCtenomysare endemic to South America. TheChacoan peccary(Catagonus wagneri), locally known astauga,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.[9]

Due to the climate of the Gran Chaco,herpetofaunaare restricted to moistrefugiain various places throughout the chaco. Rotting logs, debris piles, old housing settlement, wells, and seasonal farm ponds are examples of such refugia.[10]Theblack-legged seriema(Chunga burmeisteri),blue-crowned parakeet(Aratinga acuticadauta),Picui ground dove(Columbina picui),guira cuckoo(Guira guira),little thornbird(Phacellodomus sibilatrix), andmany-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.[11]

Conservation issues[edit]

Sorghum harvest 2008, Linea 14, Agua Dulce Region,Alto Paraguay

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'sMennonite coloniesare 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.[12]

Two factors may substantially change the Chaco in the near future: low land valuations[13][14]and the region's suitability to growfuel crops.Suitability for the cultivation ofJatrophahas been proven.[15][16]Sweet sorghumas an ethanol plant may prove viable, too, since sorghum is a traditional local crop for domestic and feedstock use. The feasibility ofswitchgrassis currently being studied by Argentina'sInstituto Nacional de Tecnología Agropecuaria,[17]as is theKaranda’y palm treein the Paraguayan Chaco.[18]

While advancements in agriculture can bring some improvements in infrastructure and employment for the region,loss of habitatand virgin forest is substantial and will likely increasepoverty.Paraguay, after having lost more than 90% of its Atlantic rainforest between 1975 and 2005, is now losing itsxerophytic forest(dry forests) in the Chaco at an annual rate of 220,000 hectares (540,000 acres) (2008).[19]In mid-2009, a projected law, initiated by theLiberal Party,that would have outlaweddeforestationin 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.[20]According toFundación Avina,a local NGO, on average, 1,130 ha (2,800 acres) are cleared per day. Thesoyplantations 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, butillegal loggingcontinues.[21]

Among the aggressive investors in the Paraguayan Gran Chaco are U.S.-based agribusinessesCargill Inc.,Bunge Ltd.,andArcher Daniels MidlandCo.[22]

Protected areas[edit]

A 2017 assessment found that 176,715 km2,or 22%, of the ecoregion is in protected areas.[1]

In September 1995, theKaa-Iya del Gran Chaco National Park and Integrated Management Natural Areawas established in an area of the Chaco in Bolivia. It is administered and was established solely by theindigenous peoples,including theIzoceño Guaraní,theAyoreode,and theChiquitano.

Other protected areas includeDefensores del Chaco National ParkandTinfunqué National Parkin Paraguay, andCopo National ParkandEl Impenetrable National Parkin Argentina.

See also:National Parks in the Chaco, Paraguay

Administrative divisions in the Gran Chaco[edit]

Dam on theRío Negro,nearResistencia, Chaco(Argentina); the torrential rains that follow the region's long dry season make flood-control works critical.
Tobafamily,Formosa Province,Argentina, 1892
Ajaguarat rest in theFormosa ProvinceWildlife Rehabilitation Center

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

Region Nation
Chaco Province Argentina
Córdoba Province
Formosa Province
Salta Province
Santa Fe Province
Santiago del Estero Province
Tucumán Province
Beni Department Bolivia
Chuquisaca Department
Santa Cruz Department
Cochabamba Department
Tarija Department
Alto Paraguay Department Paraguay
Boquerón Department
Presidente Hayes Department
State of Mato Grosso do Sul Brazil

Indigenous peoples[edit]

Main article:Gran Chaco people

Many of these peoples speak or used to speakMataco–Guaicuru languages.[24]

See also[edit]

References[edit]

  1. ^abEric Dinerstein, David Olson, et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545; Supplemental material 2 table S1b.doi:10.1093/biosci/bix014
  2. ^Don Nicol."A postcard from the central Chaco"(PDF).Archived fromthe original(PDF)on 2009-02-26.Retrieved2009-01-23.alluvial sandy soils have P (phosphorus) levels of up to 200–300 ppm
  3. ^"Paraguay encontró petróleo cerca de la frontera con la Argentina"Archived2019-03-02 at theWayback MachineLa Nación,26 November 2012(in Spanish)
  4. ^"The Gran Chaco".WWF.Retrieved2017-07-06.The Gran Chaco was one of the last frontiers in South America – but agricultural development, largely driven by soy, is gathering pace.
  5. ^abWhat is Gran Chaco vegetation in South America? I. A review. Contribution to the study of flora and vegetation of Chaco. V. Candollea, 48: 145–172, 1993.
  6. ^abNapamalo: The Giant Anteater of the Gran Chaco, 2003.
  7. ^Conservation ecology of armadillos in the Chaco region of Argentina, 1: 16-17, Edentata, 1994.
  8. ^Guiá de los Mamiferos Argentinos, 19840.
  9. ^Catagonous, an "extinct" peccary, alive in Paraguay, 189:379-381, Science, 1975.doi:10.1126/science.189.4200.379
  10. ^Ecological Notes on the Paraguayan Chaco Herpetofauna, 12(3), 433-435, Journal of Herpetology, 1978.JSTOR1563636
  11. ^"A Zoogeographic Analysis Of The South American Chaco Avifauna", 154(3), 165–352,Bulletin of the American Museum of Natural History,1975.hdl:2246/608
  12. ^de la Sancha, Noé U., Sarah A. Boyle, Nancy E. McIntyre, Daniel M. Brooks, Alberto Yanosky, Ericka Cuellar Soto, Fatima Mereles, Micaela Camino, and Richard D. Stevens. "The disappearing Dry Chaco, one of the last dry forest systems on earth." Landscape Ecology 36 (2021): 2997-3012.https://doi.org/10.1007/s10980-021-01291-x
  13. ^"Impenetrable olvido (..tan bajo el valor de la tierra que con dos campañas, sobra..)"(in Spanish). AMBIENTE-ARGENTINA. Archived fromthe originalon 2012-07-09.Retrieved2008-09-09.
  14. ^"Cada vez más Uruguayos compran campos Guaranés"(PDF)(in Spanish). Consejo de Educacion Secundaria de Uruguay. 26 June 2008. Archived fromthe original(PDF)on 25 February 2009.
  15. ^"Jatropha en el Chaco"(in Spanish). Diario ABC Digital.Retrieved2008-09-09.
  16. ^"Jatropha Chaco"(in Spanish). Incorporación del cultivo Jatropha Curcas L en zonas marginales de la provincia de chaco. Archived fromthe originalon 2008-10-11.Retrieved2008-09-09.
  17. ^"Aprovechamiento de recursos vegetales y animales para la produccion de biocombustibles"(PDF)(in Spanish). INTA. 26 June 2008. Archived fromthe original(PDF)on 26 September 2010.
  18. ^"Varias iniciativas están en marcha con vistas a la producción de biodiesel"(in Spanish). RIEDEX / Ministerio de Industria y Comercio (de Paraguay). Archived fromthe originalon 2009-03-08.Retrieved2008-09-09.
  19. ^"Deforestation in Paraguay: Over 1500 football pitches lost a day in the Chaco".World Land Trust. 30 November 2009. Archived fromthe originalon 23 August 2010.Retrieved14 January2010.
  20. ^H. Ricardo Grau, Ignacio Gasparri (27 June 2008)."Deforestation and fragmentation of Chaco dry forest in NW Argentina (1972–2007)".Archived fromthe originalon 1 February 2013.
  21. ^Bernio, Julio César (24 September 2013)."Conquest by chainsaw".www.dandc.eu.
  22. ^MacDonald, Christine (2014-07-28)."The Tragic Deforestation of the Chaco".Rolling Stone.Retrieved2017-07-06.
  23. ^abcdefghijklm"Cultural Thesaurus."Archived2011-04-29 at theWayback MachineNational Museum of the American Indian.(retrieved 18 Feb 2011)
  24. ^Campbell, Lyle;Grondona, Verónica (2012). "Languages of the Chaco and Southern Cone". In Grondona, Verónica; Campbell, Lyle (eds.).The Indigenous Languages of South America.The World of Linguistics. Vol. 2. Berlin: De Gruyter Mouton. pp. 625–668.ISBN9783110255133.

Further reading[edit]

  • Gordillo, Gastón. "Places and academic disputes: the Argentine Gran Chaco." inA Companion to Latin American Anthropology(2008): 447–465.online
  • Hirsch, Silvia et al. eds.Reimagining the Gran Chaco: Identities, Politics, and the Environment in South America(University Press of Florida, 2021)excerptalso seeonline review
  • Krebs, Edgardo, and José Braunstein. "The renewal of Gran Chaco studies."History of Anthropology Newsletter28.1 (2011): 9–19.online
  • Le Polain de Waroux, Yann, et al. "Rents, actors, and the expansion of commodity frontiers in the Gran Chaco."Annals of the American Association of Geographers108.1 (2018): 204–225.online
  • Mendoza, Marcela. "The Bolivian Toba (Guaicuruan) Expansion in Northern Gran Chaco, 1550–1850."Ethnohistory66.2 (2019): 275–300.online

External links[edit]

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Gran Chaco.

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