Guianan Moist Forests Ecoregion (South America)

Guianan Moist Forests Ecoregion (South America)

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Located on the northeast coast of South America, the Guianan moist forests are one of the world's most extensive continuous tracts of relatively pristine lowland tropical rainforest. As a result, it holds a wide variety of regional biodiversity with high species endemism and richness levels.

Guianan Moist Forests

The Guianan moist forests, also known as the Guianan lowland moist forests, are one of the world's most extensive tracts of relatively pristine lowland tropical rainforests. This ecoregion is located on the northeast coast of South America. The Amazon Basin lies to the south, and the Orinoco borders on the west.

The Guianan moist forests ecoregion covers most of the Guianas: Guyana, Suriname and French Guiana. In addition, it covers parts of eastern Venezuela and the north of the Brazilian states of Pará and Amapá. It has a total area of 51,281,764 ha (126,720,000 acres).

These forests' local and regional climate types are generally hot and wet and are strongly influenced by the northeastern trade winds and the Intertropical Convergence Zone. The result is that moisture-rich air is constantly blown inland from the Atlantic, regulated by annual oscillations of the ITCZ.

There is some variation in precipitation through the region, ranging between 2000 - 4000 mm (79 - 157 in) annually. Yearly average temperatures are a minimum of 21.5 °C (70.7 °F) and a maximum of 30.5 °C (86.9 °F) with a mean of 26 °C (79 °F).

Flora and Fauna

The Guianan moist forests encompass a large block of lowland and submontane forests, with a wide variety of regional and local floral and faunal biodiversity and high levels of species endemism and richness.

Since the first explorers and biologists arrived here, this area has been recognized as an essential center and dispersal route for many species.

An estimated 8,000 vascular plant species are in the Guianan moist forests, of which half may be endemic. The forest plant species change from east to west, with species dominant in one area completely missing from another. There are also patches of savanna, and the coastal lowlands have patches of herbaceous swamp.

The flora is diverse. The upper tiers of the forest may reach a height of 40 m (130 ft). The trees are mainly evergreen but may shed leaves in the dry season. The trees hold many epiphytes and parasites, and shrubs and herbaceous plants cover the forest floor.

More than 220 species of mammals have been identified in Guyana alone, of which more than 100 are bats. Endangered mammals include the black-bearded saki (Chiropotes satanas) and giant otter (Pteronura brasiliensis).

Endemic species include rufous mouse opossum (Marmosa lepida), six-banded armadillo (Euphractus sexcinctus), red-handed tamarin (Saguinus midas) white-faced saki(Pithecia pithecia), red-faced spider monkey (Ateles paniscus), Neotropical pygmy squirrel (Sciurillus pusillus), delicate pygmy rice rat(Oligoryzomys delicatus), Guiana bristly mouse (Neacomys guianae), Bahia porcupine (Coendou insidiosus), white-faced spiny tree-rat (Echimys chrysurus), Schultz's round-eared bat (Lophostoma schulzi), and rufous dog-faced bat (Molossops neglectus).

Bird diversity is high, with over 668 species recorded in Suriname and 786 in Guyana. These include the Guianan cock-of-the-rock (Rupicola rupicola), hoatzin (Opisthocomus hoazin), harpy eagle (Harpia harpyja), and crested eagle(Morphnus guianensis).

Endangered birds include the sun parakeet (Aratinga solstitialis) and yellow-bellied seedeater (Sporophila nigricollis).

The herpetofauna of the Guianan moist forests region includes three caimans, four amphibians, 43 lizards, 88 snakes, and ten non-marine turtles. Threatened reptiles include the black caiman and the yellow-headed side-neck turtle.

Reptiles include the threatened black caiman (Melanosuchus niger) and yellow-spotted river turtle (Podocnemis unifilis). In addition, there are diverse amphibians in the Hylidae, Poison dart frog (Dendrobatidae), and Leptodactylidae families.

Protection Status

Human colonization of the interior has only just begun in this ecoregion, as have conservation efforts. One obstacle to conservation initiatives is that this ecoregion encompasses five countries with five separate cultures, languages, and government agendas.

However, management and conservation occur nationally, with French Guiana, Guyana, and Suriname estimated at 80% of natural habitats intact.

Central Suriname Nature Reserve is the largest protected area in the Guianan Shield, accounting for almost 10% of Suriname, and is a UNESCO World Heritage Natural Site.

Map depicting the location of the Guianan moist forests ecoregion (in purple)

Map depicting the location of the Guianan moist forests ecoregion (in purple)