Orinoco River & Flooded Forests

About the Area

The Orinoco's varzea freshwater ecosystems form one of the world's most extensive areas of seasonally inundated forests.
Migrations of fish and terrestrial animal populations into the flooded forests are timed to coincide with the rising waters that flood large areas of the forest floor.

More than 1000 fish species are estimated to occur in the entire Orinoco basin, the majority of which may be endemic.

Local endemism is high, resulting from the diversity of aquatic habitats that include llanos (grassy plains), high-gradient mountain streams, white-sand flooded forests, and large river environments.

Local Species
Among the numerous fish found here are a number of well-known game and aquarium species such as Peacock bass or Speckled pavon (Cichla temensis), Blackspot pirahna (Pygocentrus cariba), Cachama (Piaractus brachyponum), and Red oscar (Astronotus ocellatus).

These waters are also home to the critically endangered Orinoco crocodile (Crocodylus intermedius) and Giant river otter (Pteronura brasiliensis), both of which suffer largely from hunting.

Threats
Threats include pollution, siltation from mining and deforestation, conversion for agriculture, livestock grazing, intensive logging, and hunting of sensitive larger vertebrates. Large dams and water diversions are planned for several major tributaries, and these would destroy the hydrologic processes that support this ecoregion's aquatic fauna.

Resources

Size:
983,000 sq. km (400,000 sq. miles)

Habitat type:
Large Rivers

Geographic Location:
Northern South America: Brazil, Columbia, and Venezuela

Conservation Status:
Relatively Stable/Intact

Quiz Time!

Which animal is South America's largest predator?

Answer:
The Orinoco Crocodile! The males at one time reached lengths of 7 m, now due to overhunting of the larger specimens the average size 5 m. Females are generally smaller, reaching lengths of 3.2 m. Orinoco crocodiles are extremely rare; there are only between 250-700 left in the wild.

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