Llanos: Grassland Ecoregion (South America)

Llanos: Grassland Ecoregion (South America)

Mon, 10/08/2018 - 20:17
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The Llanos (Los Llanos) is a vast tropical grassland plain situated to the east of the Andes Mountains in northwestern South America, within Colombia and Venezuela. It is an ecoregion of the flooded grasslands and savannas biome.

Llanos: Grassland Ecoregion

The Llanos (Los Llanos) is a vast tropical grassland plain situated to the east of the Andes Mountains in northwestern South America, within Colombia and Venezuela. It is an ecoregion of the flooded grasslands and savannas biome.

The grassland region occupies an area of approximately 570,000 sq km (220,000 sq mi), a large elongated area 1200-1300 km (750-800 mi) long, located in western Venezuela and northeastern Colombia. This is an area of extensive plains, covered mainly by savanna vegetation, of great economic importance for both Venezuela and Colombia.

This ecoregion is relatively young, perhaps less than 10,000 years old, and developed in a great geosyncline between the Guiana Plateau and the Andes Range.

This extensive basin was, over time, filled with sediments from the Guiana Plateau and the cordilleras during the tertiary. The ecoregion then experienced a series of subsidences resulting in a landscape made up mainly of alluvial plains and highlands

The main river in the region is the Orinoco, which forms part of the border between Colombia and Venezuela and is the major river system of Venezuela.

This area is delimited by the Andes to the north and west, the Guaviare River and the Amazon River Basin to the south and the lower Orinoco River and the Guiana Highlands to the east.

The Llanos ecoregion extends in a gentle curve in a northeast direction, beginning at the foothills of the Oriental Andes of Colombia and extending along the course of the Orinoco River, almost to its delta at the sea.

Llanos ecoregion location map

Llanos ecoregion location map

The ecoregion is located in a great depression, limited by the Andes in the west, the Venezuelan coastal range that isolates it from the Caribbean Sea in the north, and the Guiana Shield in the south.

The elevations of the Llanos, rising from the Llanos Bajos (“Low Plains”) west of the Orinoco River to the Llanos Altos (“High Plains”) below the Andes, rarely exceed 300 m (1,000 ft).

This ecoregion has a typical savanna climate, with a well-defined wet and dry season and high temperature all year round.

During the rainy season from May to October, parts of the Llanos can flood. This turns the woodlands and grassland into a temporary wetland, comparable to the Pantanal of central South America. This flooding also makes the area unique for its wildlife.

The area supports around 70 species of water birds, including the scarlet ibis. A large portion of the distribution of the white-bearded flycatcher is in the Llanos.