Guianan Freshwater - A Global Ecoregion
The tallest waterfall in the world
Snapshot: Ecoregion 178
Size:
510,000 sq. km (200,000 sq. miles)
Habitat type:
Small Rivers
Geographic Location:
Northeastern South America: Brazil, French Guiana (France), Suriname, and Venezuela
Conservation Status:
Relatively Stable/Intact
Did You Know!
So much water from the Guianan Freshwater ecoregion flows into the Atlantic that it changes the temperature of the ocean. The presence of all this freshwater creates the Guiana Current, a flow of surface water that's much warmer than the surrounding ocean water usually is.
About the Area
The coastal rivers of this ecoregion drain an area called the Guyana Shield and contain a wide range of flowing water habitats that include cataracts, rapids, and riparian flooded forests among others.
Though poorly investigated, these rivers are known to support a very diverse, highly intact, and notably endemic freshwater fauna.The tallest waterfall in the world - the 3,200 feet (980 m) Angel Falls - is in this ecoregion along with some of the Earth's oldest land formations. In many rivers, waterfalls have created isolated bodies of water, where many endemic species have evolved.
Local Species
Among the numerous species found in this important freshwater system are the imperiled Arapaima (Arapaima gigas), giant South American river turtle (Podocnemis expansa), Black caiman (Melanosuchus niger), and Arowana (Osteoglossum bicirrhosum).
This ecoregion provides some of the best remaining habitat for Giant river otter (Pteronura brasiliensis).
Threats
The freshwater habitats of this ecoregion are relatively intact and support generally stable freshwater populations. However, valuable game species such as the enormous arapaima and some reptiles are imperiled as a result of over-exploitation and illegal border trade.
Further human activities such as deforestation, mining, agriculture, industrial and domestic waste discharge, and water extraction have led to serious problems such as erosion, sedimentation, cyanide spills, altered hydrologic regimes, pollution, and wildfires.
Resources
• NationalGeographic.com
