Llanos: Grassland Plains

The Llanos (Los Llanos) is a vast tropical grassland plain situated east of the Andes Mountains in northwestern South America, within Colombia and Venezuela. It is an ecoregion of the flooded grasslands and savannas terrestrial 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 area of extensive plains, covered mainly by savanna vegetation, is 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.

The Andes delimits this area 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.

The ecoregion is located in a great depression. The Andes limit it in the west, the Venezuelan coastal range isolating it from the Caribbean Sea north and the Guiana Shield 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 temperatures all year round.

During the rainy season, parts of the Llanos can flood from May to October. 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.

_{Map depicting the location of the Llanos ecoregion (in purple)}