Guianan mangroves
| Guianan mangroves (NT1411) | |
|---|---|
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| Ecology | |
| Realm | Neotropical |
| Biome | Mangrove |
| Geography | |
| Area | 14,500 km2 (5,600 sq mi) |
| Countries | French Guiana, Suriname, Guyana, Venezuela |
| Coordinates | 5°58′55″N 55°38′13″W / 5.982°N 55.637°WCoordinates: 5°58′55″N 55°38′13″W / 5.982°N 55.637°W |
| Climate type | Af: equatorial, fully humid |
The Guianan mangroves (NT1411) is a coastal ecoregion of southeastern Venezuela, Guyana, Suriname and French Guiana. The mangroves provide an important habitat for migrating birds that winter in the area. Large areas are intact, although they are threatened by destruction of the trees for timber and to make way for agriculture, and from upstream agricultural and industrial pollution.
The Guianan mangroves ecoregion extends along the Atlantic coasts of southeastern Venezuela, Guyana, Suriname and French Guiana. It covers an area of about 14,500 square kilometres (5,600 sq mi) between the deltas of the Orinoco and Oyapock rivers. It includes the Gulf of Paria and the delta of the San Juan River. The largest part is in Venezuela in and around the Orinoco delta.
The mangroves lie between the sea and areas of Orinoco Delta swamp forests, Guianan moist forests and Guianan Freshwater swamp forests. The Guianan mangroves ecoregion is part of the 31,855 square kilometres (12,299 sq mi) Guianan-Amazon Mangroves global ecoregion, which also contains the Amapa mangroves, Pará mangroves and Maranhão mangroves ecoregions.
Elevations in the flat, narrow strip of coastal land covered by the mangroves range from sea level to about 4 metres (13 ft) above sea level. Sand and shell ridges and elevated mud flats are formed by accumulated sediments, carried steadily westward from the mouth of the Amazon by strong ocean currents. The mud flats evolve into clay flats occupied by some species of mangrove. The coastlines suffer periodically from extensive erosion after large number of mangroves die at the same time. Other habitats are brackish or salt lagoons, brackish herbaceous swamps, swamp woods and swamp forests. The swamps are a source of fresh water to the mangroves.
The alluvial plains in the northwest have different characteristics. The San Juan delta has swamps with marine-fluvial sediment deposits, the Gulf of Paria has marine sediments and the Orinoco delta has mainly fluvial sediments. The tides are no more than 1.3 metres (4 ft 3 in) in the Orinoco delta. The Oronoco river has an average flow of 36,000 cubic metres (1,300,000 cu ft) per second, and deposits 200,000 tons of sediment each year, resulting in a very unstable landscape.
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Wikipedia