The Humid Chaco ( Spanish: ''Chaco Húmedo'' or ''Chaco Oriental'') is a tropical grasslands, savannas, and shrublands

ecoregion An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. It lies in the basin of the

Paraná River The Paraná River ( ; ; ) is a river in south-central South America, running through Brazil, Paraguay, and Argentina for some ."Parana River". Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2012. Web. ...

, covering portions of central

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 ...

and 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 with a small portion of southwestern

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

and northwestern

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

. The natural vegetation is a mosaic of grasslands, palm savanna, and forest.

Geography

The Humid Chaco lies in the lowlands of the Paraná river and its tributaries, including the

Paraguay River The Paraguay River (''Ysyry Paraguái'' in Guarani language, Guarani, ''Rio Paraguai'' in Portuguese language, Portuguese, ''Río Paraguay'' in Spanish language, Spanish) is a major river in south-central South America, running through Brazil, Bol ...

. It is bounded on the west by the Dry Chaco, a semi-arid region of dry forests and savannas. The Alto Paraná Atlantic forests lie to the east, and the

Cerrado The Cerrado () is a vast ecoregion of Tropics, tropical savanna in central Brazil, being present in the states of Goiás, Mato Grosso do Sul, Mato Grosso, Tocantins, Maranhão, Piauí, Bahia, Minas Gerais, São Paulo (state), São Paulo, Paraná ...

grasslands to the northeast. It borders on some large

flooded grasslands and savannas Flooded grasslands and savannas is a terrestrial biome of the World Wide Fund for Nature (WWF) biogeographical system, consisting of large expanses or complexes of flooded grasslands. These areas support numerous plants and animals adapted to th ...

, including the Paraná flooded savanna along the lower Paraná and Paraguay rivers, 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 ...

to the north, and the Southern Cone Mesopotamian savanna to the southeast between the Paraná and

rivers. The topography is generally flat or gently rising, and the soils are mostly fine alluvium deposited by the area's rivers. Asuncion, Paraguay's capital, lies in the ecoregion.

Climate

The climate is tropical, becoming subtropical towards the south. Average annual rainfall generally decreases towards the west, and ranges from 1,300 mm in the wetter eastern portions to 750 mm in the west near the transition to the Dry Chaco. Rainfall is highest in the summer months (January to April) and lowest in the winter months (June to August).

Flora

The flora is a mosaic of grassland, savanna, forests, and bogs. Grasslands and savannas are generally found on higher ground, and forests along streams and in river floodplains. Bogs form seasonally or year-round over impermeable soil layers. Grasslands are characterized by tall, coarse grass. Palm savannas are common, including the palm '' Copernicia alba''. The most common trees in the forests are quebracho colorado ('' Schinopsis balansae'') and quebracho blanco ('' Aspidosperma quebracho-blanco''), together with guayacán ('' Caesalpinia paraguariensis''), espina corona (''

Gleditsia amorphoides ''Gleditsia amorphoides'' common name Espina de Corona Cristi, is a tree in the subfamily Caesalpinoidae family Fabaceae. It is native to South America South America is a continent entirely in the Western Hemisphere and mostly in the So ...

''), urunday ('' Myracrodruon balansae''), viraró ('' Ruprechtia laxiflora''), palo piedra ('' Diplokeleba floribunda''), guayaibí ('' Patagonula americana''), zapallo caspini ('' Pisonia zapallo''), lapacho negro ('' Tabebuia ipe''), palo borracho del flor rosada ('' Chorisia speciosa''), and itin ('' Prosopis kuntzei'').

Fauna

Native mammals include puma (''Puma concolor''),

jaguar The jaguar (''Panthera onca'') is a large felidae, cat species and the only extant taxon, living member of the genus ''Panthera'' that is native to the Americas. With a body length of up to and a weight of up to , it is the biggest cat spe ...

(''Panthera onca''),

maned wolf The maned wolf (''Chrysocyon brachyurus'') is a large canine of South America. It is found in Argentina, Brazil, Bolivia, Peru, and Paraguay, and is almost extinct in Uruguay. Its markings resemble those of a red fox, but it is neither a fox nor ...

(''Chrysocyon brachyurus''), red brocket (''Mazama americana''), gray brocket (''Mazama gouazoubira''), marsh deer (''Blastocerus dichotomus''), pampas deer (''Ozotoceros bezoarticus''), White-lipped peccary (''Tayassu pecari''),

collared peccary The collared peccary (''Dicotyles tajacu'') is a peccary, a species of artiodactyl (even-toed) mammal in the family Peccary, Tayassuidae found in North America, North, Central America, Central, and South America. It is the only member of the gen ...

(''Tayassu tajacu''),

giant anteater The giant anteater (''Myrmecophaga tridactyla'') is an Insectivore, insectivorous mammal native to Central America, Central and South America. It is the largest of the four living species of anteaters, which are classified with sloths in the or ...

(''Mymercophaga tridactyla''),

capybara The capybara or greater capybara (''Hydrochoerus hydrochaeris'') is the largest living rodent, native to South America. It is a member of the genus '' Hydrochoerus''. The only other extant member is the lesser capybara (''Hydrochoerus isthmi ...

(''Hydrochaerys hydrochaeris''), black howler monkey (''Alouatta caraya''), and Azara’s night monkey (''Aotus azarae''). Birds species include the greater rhea or ñandú (''Rhea americana''), undulated tinamou (''Crypturellus undulatus''), savanna hawk (''Buteogallus meridionalis''), and pale-crested woodpecker (''Celeus lugubris'').

Protected areas

A 2017 assessment found that 35,949 km², or 12%, of the ecoregion is in protected areas. Protected areas include Chaco National Park, Río Pilcomayo National Park, and Mburucuyá National Park in Argentina, and Ypoá National Park in Paraguay. The Iberá Wetlands, located in the southeast of the ecoregion adjacent to the Southern Cone Mesopotamian savanna, are protected by Argentina's Iberá Provincial Reserve and Iberá National Park.

References

External links

* {{WWF ecoregion, id=nt0708, name=Humid Chaco La Plata basin Ecoregions of South America Ecoregions of Argentina Ecoregions of Brazil Ecoregions of Paraguay Neotropical ecoregions Tropical and subtropical grasslands, savannas, and shrublands