| Humid Chaco | |
|---|---|
 NearResistencia, Chaco, NortheasternArgentina | |
 | |
| Ecology | |
| Realm | Neotropical |
| Biome | tropical and subtropical grasslands, savannas, and shrublands |
| Borders | |
| Geography | |
| Area | 291,596 km2 (112,586 mi2) |
| Countries | |
| Conservation | |
| Protected | 35,949 km² (12%)[1] |
TheHumid Chaco (Spanish:Chaco Húmedo orChaco Oriental) is atropical grasslands, savannas, and shrublandsecoregion inSouth America. It lies in the basin of theParaná River, covering portions of centralParaguay and northernArgentina, and with a small portion of southwesternBrazil and northwesternUruguay. The natural vegetation is a mosaic of grasslands, palm savanna, and forest.
The Humid Chaco lies in the lowlands of the Paraná river and its tributaries, including theParaguay River. It is bounded on the west by theDry Chaco, a semi-arid region of dry forests and savannas. TheAlto Paraná Atlantic forests lie to the east, and theCerrado grasslands to the northeast. It borders on some largeflooded grasslands and savannas, including theParaná flooded savanna along the lower Paraná and Paraguay rivers, thePantanal to the north, and theSouthern Cone Mesopotamian savanna to the southeast between the Paraná andUruguay rivers.[2]
The topography is generally flat or gently rising, and the soils are mostly fine alluvium deposited by the area's rivers.
Asunción, Paraguay's capital, lies in the ecoregion.
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.[2] Rainfall is highest in the summer months (January to April) and lowest in the winter months (June to August).
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.[2]
Grasslands are characterized by tall, coarse grass. Palm savannas are common, including the palmCopernicia 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), 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).[2]
Native mammals includepuma (Puma concolor),jaguar (Panthera onca),maned wolf (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 (Tayassu tajacu),giant anteater (Mymercophaga tridactyla),capybara (Hydrochaerys hydrochaeris),black howler monkey (Alouatta caraya), andAzara’s night monkey (Aotus azarae).[2]
Birds species include thegreater rhea or ñandú (Rhea americana),undulated tinamou (Crypturellus undulatus),savanna hawk (Buteogallus meridionalis), andpale-crested woodpecker (Celeus lugubris).[2]
A 2017 assessment found that 35,949 km², or 12%, of the ecoregion is in protected areas.[1]
Protected areas includeChaco National Park,Río Pilcomayo National Park, andMburucuyá National Park in Argentina, andYpoá National Park in Paraguay. TheIberá Wetlands, located in the southeast of the ecoregion adjacent to theSouthern Cone Mesopotamian savanna, are protected by Argentina'sIberá Provincial Reserve andIberá National Park.
