Guayanan Highlands moist forests

The Guayanan Highlands moist forests (NT0124) is an ecoregion in the south of Venezuela and the north of Brazil and in Guyana, Suriname, French Guiana. It is in the Amazon biome.
It encompasses an upland region with diverse fauna and flora, which contains dramatic tepuis, or sandstone table mountains.
The region has been inaccessible in the past and is generally fairly intact, apart from the north and northeast where large scale agriculture, ranching and mining operations are steadily encroaching on the ecosystem. New roads are opening the interior to logging, and planned dams will have a drastic impact on the riparian zones.

Location

The ecoregion includes parts of southern Venezuela, western and southern Guyana and northern Brazil, with scattered portions in Suriname and French Guiana.
It extends into eastern Colombia.
It has a total area of .
The ecoregion lies on the Guiana Shield, an ancient upland area between the Amazon and Orinoco basins.
It is surrounded by lowland grassy savannas and lowland forest.
All areas of the ecoregion contains enclaves of the Pantepuis ecoregion on the tops of table mountains.

Most areas of the ecoregion in the east are surrounded by the Guianan moist forests ecoregion, and most areas in the west are surrounded by the Guianan piedmont and lowland moist forests ecoregion.
Sections of the ecoregion in the east border the Uatuma-Trombetas moist forests to the south.
The central part of the ecoregion surrounds the northern part of the largest section of the Guianan savanna ecoregion
The southwestern part of the ecoregion rises above the Negro-Branco moist forests ecoregion.
The Guayanan Highlands moist forests and the Tepuis together make up the Guayanan Highlands Forests Global 200 ecoregion.

Physical

The terrain is rugged, with elevations in the ecoregion from above sea level.
Taller table mountains in the region rise to elevations of and host the Tepui ecoregion.
The Guayanan Highlands ecoregion is an "island" of higher land surrounded by lower grasslands and forests collectively known as the Guiana Shield.
Most of the land drains into the Orinoco through the Ventuari, Caroní, Paragua and Caura rivers in Venezuela.
In the south, it is drained by the Uraricoera and Branco rivers in Brazil into the Amazon.

The upland terraces and mountains consist mainly of quartzitic or sandstone rocks, with granitic rock in some areas.
The lowland plains are recent, formerly flooded by lakes or by the sea.
Most of the landscape is forest-covered rolling peneplains and floodplains.
The undulating peneplains between the Caura and Paragua rivers hold low hills up to high.
There are scattered upland areas of undulating plains, rounded hills, low mountains and Tepuis up to high, and the lower slopes of the higher tepuis.
Soils are mostly sandy and low in nutrients.

Ecology

The Guianan Highlands moist forests ecoregion is in the Neotropical realm and the tropical and subtropical moist broadleaf forests biome.

Climate

The Köppen climate classification is "Am": equatorial, monsoonal.
Temperatures vary little throughout the year.
Yearly average temperatures range from a minimum of to a maximum of , with a mean of .
Annual rainfall varies considerably, but in some areas averages .
Monthly rainfall is lowest in January at and highest in July at .

Flora

There are various habitats including large areas of tall primary rainforest, open savannas and gallery forests.
The peneplains hold evergreen forests with dense canopies of with emergent trees in the Calophyllum, Anacardium, Manilkara, Protium, Inga, Parkia, Copaifera, Erythrina and Dipteryx genera.
Common trees on the plains include ''Micropholis melinoniana'', Dacryodes species, ''Euterpe precatoria'' and '' Quassia cedron''.
There are fewer emergent trees in the hilly areas, where tree species include '' Newtonia suaveolens'', '' Couratari guanensis'', Alexa species, ''Euterpe precatoria'' and ''Micrandra minor''.

The seasonally flooded forests along the rivers have similar formations of flora to the Amazon region.
Common tree species on the upper Orinoco include '' Combretum frangulifolium'', '' Gustavia augusta'', Pterocarpus species, '' Etaballia dubia'', '' Albizia corymbosa'', '' Spondias mombin'', '' Mabea nitida'', '' Eschweilera tenuifolia'', '' Astrocaryum aculeatum'' and Inga species.
Floodplain trees include '' Caryocar microcarpum'', '' Caraipa densifolia'', '' Macrolobium acaciaefolium'', '' Abuta grandfolia'' and ''Panopsis rubescens''.

Fauna

209 species of mammals have been recorded, including jaguar (''Panthera onca''), cougar (''Puma concolor''), South American tapir (''Tapirus terrestris''), white-lipped peccary (''Tayassu pecari''), collared peccary (''Pecari tajacu''), brocket deer (Mazama genus), white-eared opossum (''Didelphis albiventris''), big lutrine opossum (''Lutreolina crassicaudata''), Robinson's mouse opossum (''Marmosa robinsoni''), Davy's naked-backed bat (''Pteronotus davyi''), Fernandez's sword-nosed bat (''Lonchorhina fernandezi''), highland yellow-shouldered bat (''Sturnira ludovici''), eastern lowland olingo

HOME


Content is Copyleft
Website design, code, and AI is Copyrighted (c) 2014-2017 by Stephen Payne


Consider donating to Wikimedia



As an Amazon Associate I earn from qualifying purchases