Pantepui Forests and Shrublands Ecoregion (South America)

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Pantepui Forests and Shrublands Ecoregion (South America)

Fri, 03/29/2019 - 16:07
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The Pantepui forests and shrublands ecoregion in the Guiana Highlands of northern South America hosts an archipelago of more than 50 tabletop mountains with isolated sandstone plateaus and summits atop nearly vertical escarpments called tepuis.

Pantepui Forests and Shrublands

The Pantepui forests and shrublands ecoregion in the Guiana Highlands of northern South America hosts an archipelago of more than 50 tabletop mountains with isolated sandstone plateaus and summits atop nearly vertical escarpments called tepuis.

The tepuis are the remains of the ancient sandstone tableland overlying the even more ancient granitic Guiana Shield.

More than 50 of the highest tabletop mountains are the remains of the ancient sandstone tableland overlying the even more ancient granitic Guiana Shield. They range from 1,000 to 3,000 m (3,280 to 9,842 ft) in elevation. And they are called tepuis (singular: tepui), a word from the Pemón Amerindians.

Many tepuis are graced with dramatic waterfalls, the tallest of which (in fact, the tallest in the world) is Angel Falls dropping 979 m (3,212 ft).

These dramatic features in the landscape perforate an extensive matrix of highland savannas and rainforests across southern Venezuela primarily, with a few outliers in western Guyana, Suriname, and northernmost Brazil. Hundreds of smaller sandstone mountains exist in the ecoregion as well.

The Tepuis are characteristically flat-topped, steep, nearly vertical escarpments interrupted by terraced talus slopes. Some mountains present more undulating irregular summit contours. Each mountain displays its individual characteristics of shape, biodiversity, or elevation.

The highest peaks within the Pantepui forests and shrublands ecoregion are Pico da Neblina in Brazil at 3,014 m (9,888 ft), the adjacent Pico Phelps (2,992 m or 9,816 ft) in Venezuela, followed by Mount Roraima (2,810 m or 9,219 ft) and Cerro Marahuaka (2,800 m or 9,186 ft), both in Venezuela.

Cerro Ichún, close to the Brazil-Venezuela border, has the largest surface area of all the sandstone tabletop mountains with a total area of 3,260 sq km (1,258 sq mi) at an elevation of 1,400 m (4,600 ft).

On the highest summits, the temperature can drop to an extreme of 0° C (32° F). However, generally, the temperatures on the summits range from 8° to 20° C (46° to 68° F) on average over the year, depending on elevation.

The Pantepui forests and shrublands are constantly humid and receive from 2,000 to 4,000 mm (78 to 157 in) of rain yearly with a subtle dry season. As a result, soils are generally oligotrophic (low nutrient).

Flora and Fauna

The vegetation on the Tepui mountains is distinct from the surrounding Amazonian humid forest vegetation and forms a biogeographic complex. A representative tepui hosts four distinct vegetation zones starting at the base, proceeding to the talus slope, then to the escarpment (cliff) base and, finally, the mountain summit.

The vegetation on the Tepuis has a very high rate of endemism (33%). The summit vegetation is of particular interest, and it is here that the high endemism characteristic of the Tepui floristic province is found.

Five vegetation types are found on the summits:

  • forests of tall or dwarfed trees, including riverine forests
  • epiphytes in forest associations
  • shaded crevices of rocks, bluffs and ledges
  • wet or dry open savanna without rock outcrops
  • exposed rock outcrops, open sandy or rocky areas

The Pantepui forests and shrublands ecoregion hosts 186 mammal species, mainly located on the lower slopes of the mountains. This number includes nine primates that live here, including howler monkeys (Alouatta seniculus), night monkeys (Aotus trivirgatus), titi monkeys (Callicebus torquatus), black uakari (Cacajao melanocephalus), weeper capuchins (Cebus olivaceus), and white-faced sakis (Pithecia pithecia). In addition, five cats live here, including jaguars (Panthera onca) and pumas (Puma concolor).

Some mammals are restricted to this region of Amazonia; these include an endemic opossum (Marmosa tyleriana) and white-eared opossum (Didelphis albiventris), long-tailed weasels, pale-throated sloths and a great variety of bats (Diclidurus isabellus, Pteronotus personatus, Phyllostomus latifolius, Anoura geoffroyi, Glossophaga longirostris), an endemic rodent (Podoxymys roraimae), three climbing rats in the genus Rhipidomys, and two guinea pigs (Cavia).

A large number of birds are found in the Pantepui forests and shrublands ecoregion: 628 species with 41 endemics, including tepui tinamous (Crypturellus ptaritepui), fiery-shouldered parakeet (Pyrrhura egregia), tepui parrotlets (Nannopsittaca panychlora), roraiman nightjars (Caprimulgus whitelyi), tepui swifts (Cypseloides phelpsi), rufous-breasted sabrewings (Campylopterus hyperythrus), buff-breasted sabrewings (C. duidae), peacock coquettes (Lophornis pavoninus), tepui goldenthroats (Polytmus milleri), velvet-browed brilliants (Heliodoxa xanthogonys), white-throated foliage-gleaners (Automolus roraimae), tepui antpittas (Myrmothera simplex), red-banded fruiteaters (Pipreola whitelyi), three manakins (Pipra cornutai, P. pipra, and Chloropipo uniformis), among many others.

Reptiles and amphibians are abundant on the summits and slopes of the Tepuis. The more ferocious snakes that occur here include fer-de-lance (Bothrops asper), coral snakes (Micrurus spp.), boa constrictors (Boa constrictor), and bushmasters (Lachesis muta). Iguanas (Iguana iguana) are ubiquitous and tegus lizards (Tupinambis spp.) are common.

Protection Status

Due to the inaccessibility of both the steep slopes and high summits of the Tepui Mountains, much of the natural habitat is intact.

The mountains above 800 m (2,600 ft) are designated protected conservation areas as natural monuments, national parks, or biosphere reserves.

Protected areas include Monte Roraima National Park in Brazil and Canaima National Park in Venezuela.

Location map of the Pantepui forests and shrublands ecoregion (in purple)

Location map of the Pantepui forests and shrublands ecoregion (in purple)