Nichare, Caura River, Venezuela Photograph by David Olson   South America: Southern Venezuela, northern Brazil, western Guyana, and eastern Colombia Tropical and Subtropical Moist Broadleaf Forests   130,300 square miles (337,600 square kilometers) -- slightly larger than New Mexico Relatively Stable/Intact

· An Island in the Highlands
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
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An Island in the Highlands

This ecoregion sits on the Guayana Shield, which underlies the northern region of South America. The Guayana Shield is an ancient and weathered granitic dome that protrudes from an otherwise flat, lowland basin and separates the Amazon and Orinoco watersheds. It contains a diversity of habitats, including vast expanses of tall primary rain forest, open savannas with few or no trees, and rich gallery forests. This ecoregion is essentially a habitat "island" in the highlands, surrounded by lowland llanos (grassy plains) and lowland forest.

Special Features

This ecoregion is located in the highlands of southern Venezuela and northern Brazil and extends into western Guyana and eastern Colombia. Elevations range from 1,640 to 4,920 feet (500 to 1,500 m) above sea level. The climate is seasonal and humid, with 78 to 94 inches (2,000 to 2,400 mm) of rainfall annually. The landscape is a mixture of forested valleys and floodplains, steep hills and mountains, and a patchwork of undulating high plains and tepuis, which are high sandstone plateaus. Gallery forests in steep river valleys include tall evergreen forests, which contain species characteristic of both montane and lowland Amazonian habitats. This area is also characterized by its high biodiversity. Endemic and restricted-range species include a variety of rodents, bats, opossums, birds, and reptiles, as well as numerous plants.

	The fer-de-lance, a large viper found in this ecoregion, can reach 6 to 10 feet (2 to 3 m) in length. Young individuals tend to be arboreal, while adults prefer the ground, where they feed primarily on small mammals, especially opossums.

Wild Side

With small ears, large eyes, and an extremely long ringed tail, the olingo can be seen moving through the canopy at night, hunting for insects, small mammals, and fruits. Also under the cover of night, an arboreal spiny rat drinks water from a bromeliad high atop a mahogany tree. A vermiculated screech owl flies low through the branches in search of its elusive prey, a small pocket mouse. Daybreak reveals a large bushmaster, an extremely venomous snake, although it is well camouflaged between the buttresses of a giant kapok tree. A tangle of blooming vines attracts abundant hummingbirds, including five species of emeralds. Iguanas sun themselves in the upper branches of an Inga tree, while an aplomado falcon flies past overhead. A chestnut-tipped toucan hops from branch to branch grabbing fruit and then raises the tip of its bill to let the fruit drop down its throat.

Cause for Concern

Much of the interior forests of the Guayana highlands region are still intact. Habitat destruction from large-scale agriculture, mining, and cattle-raising occurs along the periphery and near urban centers. Other threats include logging, hunting, fire, colonization, and unregulated tourism. Several proposed hydroelectric dams potentially threaten vast areas of the ecoregion.

For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.