About the Humid Chaco
Giant arrowhead, Sagittaria montevidensis © M. Peña Chocarro.
The Humid Chaco is part of the Gran Chaco of South America, an area covering approximately 1.066.000 square kilometres between Argentina (62.19%), Paraguay (25.43%), Bolivia (11.61%) and Brazil (0.7%).
Extending from tropical latitudes (18° S) to subtropical zones (31° S), the Gran Chaco contains three distinct sub regions, two of which are present in Paraguay: Humid Chaco and Dry Chaco.
The Dry Chaco, in the west and centre of Paraguay, is an area with very irregular and low-intensity rains, largely covered by scrubby xeromorphic forests.
The Humid Chaco, covers an area of 4,674,000 square kilometres between Paraguay and Argentina and a small portion in Brazil. It is a lower region, strongly influenced by the basin of the Paraguay, Parana and the lower part of the Pilcomayo rivers. Most of the region extends westwards from the Paraguay river, but there are several areas east of the river where large intrusions of this ecoregions can be found.
Vegetation
The Humid Chaco is a convergence zone where species of different floras intermingle. We can find typical Chaquean species such as:
Humid Chaco landscape along the Rio Confuso © M. Peña Chocarro.
- quebracho colorado (Schinopsis balansae)
- chañar (Geoffroea decorticans)
- guayacán (Caesapinia paraguayensis)
- algarrobo negro (Prosopis nigra)
as well as species from nearby floras, such as:
- urunde’y (Astronium balansae)
- paratodo (Tabebuia aurea)
- aguai (Chrysophyllum gonocarpum)
- many others that appear along the rivers.
Zones
The typical vegetation of the Humid Chaco consists of a mosaic formation in which patches of dry forests alternate with palm savannahs dominated by Copernicia alba and wetlands.
The forests develop in the higher areas free of flooding, the palm savannahs in intermediate areas that are periodically flooded, and the wetlands in the lowest parts, which are more subject to flooding.
In addition to these vegetation units, other formations which are not exclusive of the Humid Chaco can be also found, such as gallery forest and 'paratodales' (open woody formations with Tabebuia aurea).