The Arauca River ( Spanish : Río Arauca ) rises in the Andes Mountains of north-central Colombia and ends at the Orinoco in Venezuela . For part of its run it is the boundary between Colombia and Venezuela. The major city on its banks is Arauca , Colombia and El Amparo , Venezuela.
20-748: The Arauca is typical of the rivers that flow east across the Llanos Orientales starting as a swift mountain stream and becoming wider and slower as it crosses the plains. It starts high in the Andes, in the Páramo del Almorzadero at over 4,000 metres (13,000 ft) above sea level. Initially, it is called the Chitagá, and it receives inflows from the Carabo and the Cacota, and then twists its course towards
40-577: A tropical monsoon climate in the Colombian Llanos. Rainfall is highly seasonal, with a rainy season from April to November, and a dry season between December and March. The wettest months are typically June and July. Rainfall varies across the ecoregion, from up to 3,000 millimetres (120 in) per year in the southwest, 1,200 to 1,600 millimetres (47 to 63 in) in Apure State, and 800 to 1,200 millimetres (31 to 47 in) per year in
60-655: A canopy 8 to 20 meters high, and include Inga spp., Combretum frangulifolium , Gustavia augusta , Pterocarpus sp., Pterocarpus dubius , Spondias mombin , and Copaifera pubiflora . Semi-deciduous forests occur above flood level, and form a canopy 12 to 15 meters high. Common trees include Tabebuia billbergii , Godmania aesculifolia , Cassia moschata , Spondias mombin, Copaifera pubiflora, Bourreria cumanensis , Cordia spp., Bursera simaruba , Cochlospermum vitifolium , Hura crepitans , and Acacia glomerosa . "Matorrales" are deciduous and semi-deciduous shrublands 5 to 8 meters high which cover large areas in
80-535: A hectare. During the rainy season from May to October, parts of the Llanos can flood up to a meter. This turns some savannass and grasslands into temporary wetlands , comparable to the Pantanal of central South America. This flooding also creates habitat for water birds and other wildlife. These seasonally flooded grasslands and savannas, known as llano bajo, typically have richer soils. They are characterized by
100-587: The Andes in Colombia and Venezuela , in northwestern South America. It is an ecoregion of the tropical and subtropical grasslands, savannas, and shrublands biome . The Llanos occupy a lowland that extends mostly east and west. The Llanos are bounded on the west and northwest by the Andes , and on the north by the Venezuelan Coastal Range . The Guiana Highlands are to the southeast, and
120-602: The Negro-Branco moist forests are to the southwest. To the east the Orinoco wetlands and Orinoco Delta swamp forests occupy the Orinoco Delta . The Llanos' main river is the Orinoco , which runs from west to east through the ecoregion and forms part of the border between Colombia and Venezuela. The Orinoco is the major river system of Venezuela. The ecoregion has a tropical savanna climate that grades into
140-594: The lowland paca ( Cuniculus paca ), agoutis ( Dasyprocta spp.), and Brazilian porcupine ( Coendou prehensilis ), and large cats like the puma ( Puma concolor ), jaguar ( Panthera onca ), and ocelot ( Leopardus pardalis ). The endangered giant otter ( Pteronura brasiliensis ) lives along the Orinoco and its tributaries. Some of the largest jaguars in the world are found in the Llanos, with average weights of over 100 kg (220 lb) for males. The Llanos long-nosed armadillo ( Dasypus sabanicola ) and
160-652: The African grass Melinis minutiflora , and now cover large areas. Agriculture, particularly rice and maize, now cover extensive areas, including rice fields in former seasonal wetlands. In Los Llanos, the governments of Venezuela and Colombia had developed a strong oil and gas industry in the zones of Arauca, Casanare, Guárico, Anzoátegui, Apure and Monagas. The Orinoco Belt , entirely in Venezuelan territory, consists of large deposits of extra heavy crude ( oil sands ). The Orinoco belt oil sands are known to be one of
180-623: The Llanos of Monagas State in the northeast. Mean annual temperature is 27 °C or 80.6 °F, and the average monthly temperature varies little throughout the year; the lowest-temperature months (June, July, December, and January) are only 2 °C or 3.6 °F cooler than the hottest months. The plant communities in the Llanos include open grasslands, savannas with scattered trees or clumps of trees, and small areas of forest, typically gallery forests along rivers and streams. There are seasonally flooded grasslands and savannas ( llano bajo ) and grasslands and savannas that remain dry throughout
200-1108: The central Venezuelan llanos, and may be a form of secondary vegetation in areas that were formerly dry deciduous forest. Typical shrubs are Bourreria cumanensis , Randia aculeata , Godmania aesculifolia , Pereskia guamacho , Prosopis spp., Xylosma benthamii , Erytroxylum sp., and Cereus hexagonus . Mammals of the grassland and savanna include white-tailed deer ( Odocoileus virginianus ), giant anteater ( Myrmecophaga tridactyla ), capybara ( Hydrochoerus hydrochaeris ), giant armadillo ( Priodontes maximus ), Eastern cottontail ( Sylvilagus floridanus ), Alston's cotton rat ( Sigmodon alstoni ), Hispid cotton rat ( S. hispidus ), Zygodontomys brevicauda , and Oecomys bicolor . The gallery forests are home to more diverse large and medium-sized mammals, including collared peccary ( Tayassu tajacu ), white-lipped peccary ( T. pecari ), South American tapir ( Tapirus terrestris ), white-tailed deer, red brocket ( Mazama americana ), wedge-capped capuchin ( Cebus olivaceus ), Venezuelan red howler ( Alouatta seniculus ), large rodents like
220-480: The cowhands that took care of the herds, and had some cultural similarities with the gauchos of the Pampas or the vaqueros of Spanish and Mexican Texas . Decades of extensive cattle raising has altered the ecology of the Llanos. Grasslands and savannas are frequently burned to make them more suitable for grazing and eliminate trees and shrubs. Non-native grasses have been introduced for cattle fodder, including
SECTION 10
#1732779897081240-1030: The east joining with the Culaga and the Bochaga. Its name then changes to the Margua. The Negro, the Colorado, and the San Lorenzo then flow into it. From the right bank come the Cubugón and the Cobar from the Sierra Nevada de Chita. The Tunebo Indians call this stretch the Sarare. Now flowing across a flat zone, it divides to form the Charo Island. Serving as the demarcation line between Colombia and Venezuela for 296 kilometres (184 mi) of border, on
260-694: The ecoregion's wetlands. Indigenous peoples of the Llanos include the Guahibo in the western Llanos of Colombia and Venezuela, and the Yaruro in the eastern Llanos in Venezuela. The primary economic activity in the Llanos since the Spanish colonial era is the herding of millions of cattle. An 1856 watercolor by Manuel María Paz depicts sparsely populated open grazing lands with cattle and palm trees. The term llanero ("plainsman") became synonymous with
280-514: The genera Rhynchospora and Bulbostylis . Shrubs and herbs are most commonly legumes in the genera Mimosa , Cassia , Desmodium , Eriosema , Galactia , Indigofera , Phaseolus , Stylosanthes , Tephrosia , and Zornia . The trees manteco ( Byrsonima crassifolia ), chaparro ( Curatella americana ), and alcornoque ( Bowdichia virgilioides ) are the most common, growing either as scattered trees or in woodland patches known as matas which range in area from 12 meters in diameter up to
300-425: The grass Paspalum fasciculatum . Trees include the palm Copernicia tectorum and gallery forest species. Gallery forests include evergreen seasonally flooded forests, and semi-deciduous forests on higher ground. Morichales are seasonally flooded forests characterized by the moriche palm ( Mauritia flexuosa ). Vegas are seasonally flooded evergreen forests found along the Orinoco and its tributaries. Trees form
320-1047: The largest, behind that of the Athabasca Oil Sands in Alberta , Canada. Venezuela's non-conventional oil deposits of about 1,200 billion barrels (1.9 × 10 m ), found primarily in the Orinoco oil sands, are estimated to approximately equal the world's reserves of conventional oil. A 2017 assessment found that 105,323 km², or 28%, of the ecoregion, is in protected areas. Protected areas include Aguaro-Guariquito National Park (5,857.5 km²), Cinaruco-Capanaparo National Park (5,843.68 km²), Tortuga Arrau Reserve (98.56 km²), and Caño Guaritico Wildlife Refuge (93.0 km²) in Venezuela, and El Tuparro National Natural Park (5,549.08 km²) in Colombia. 6°49′23.2″N 67°38′57.4″W / 6.823111°N 67.649278°W / 6.823111; -67.649278 Trachypogon Trachypogon
340-410: The one called Agua Limón. Various subsidiary channels are used extensively for transportation from the town of Arauca down to its mouth on the Orinoco . The course of the river is 80 percent navigable in small boats. Llanos The Llanos ( Spanish Los Llanos , "The Plains"; Spanish pronunciation: [los ˈʝanos] ) is a vast tropical grassland plain situated to the east of
360-644: The right side, the Royata, Bojabá and Banadía flow in, and on the left the Cutufí enters. From then on, it takes the name Arauca in tribute to the Araucana tribe, which inhabited the mountain ranges of the upper course and belonged to the great Arawak family. Now in the savannas of the Llanos Orientales, it often becomes a braided river with the main course splitting to form the subsidiary channels, such as
380-550: The short-tailed opossum Monodelphis orinoci are endemic to the Llanos. The Llanos' wetlands supports around 70 species of water birds , including the scarlet ibis . A large portion of the distribution of the sharp-tailed ibis ( Cercibis oxycerca ) and white-bearded flycatcher ( Phelpsia inornata ) is in the Llanos. Native reptiles include the Orinoco crocodile ( Crocodylus intermedius ), spectacled caiman ( Caiman crocodilus ), Green anaconda ( Eunectes murinus ), and Arrau turtle ( Podocnemis expansa ), which live in
400-685: The year ( llano alto ). The llano alto grasslands and savannas are characterized by grasses and shrubs 30–100 cm high, forming tussocks 10 to 30 cm apart. Soils are typically sandy and nutrient-poor. Llano alto covers approximately two-thirds of the Venezuelan llanos, and is also widespread in the Colombian llanos. Grasses of genus Trachypogon are predominant, and species include Trachypogon plumosus , T. vestitus , Axonopus canescens , A. anceps , Andropogon selloanus , Aristida spp., Leptocoryphium lanatum , Paspalum carinatum , Sporobolus indicus , and S. cubensis , and sedges in
#80919