The Guianan mangroves (NT1411) is a coastal

ecoregion An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...

of southeastern

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

Guyana Guyana, officially the Co-operative Republic of Guyana, is a country on the northern coast of South America, part of the historic British West Indies. entry "Guyana" Georgetown, Guyana, Georgetown is the capital of Guyana and is also the co ...

Suriname Suriname, officially the Republic of Suriname, is a country in northern South America, also considered as part of the Caribbean and the West Indies. It is a developing country with a Human Development Index, high level of human development; i ...

French Guiana French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west ...

and

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. The

mangrove A mangrove is a shrub or tree that grows mainly in coastal saline water, saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen a ...

s provide an important

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

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.

Location

The Guianan mangroves ecoregion extends along the Atlantic coasts of northeastern Venezuela, Guyana, Suriname, French Guiana, and Cabo Orange in Brazil. It covers an area of about between the deltas of the

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

and Oyapock rivers. It includes the

Gulf of Paria The Gulf of Paria ( ; ) is a shallow ( at its deepest) semi-enclosed inland sea located between the island of Trinidad and the east coast of Venezuela. It separates the two countries by as little as at its narrowest and at its widest points. T ...

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 The Orinoco Delta swamp forests (NT0147) is an ecoregion of eastern Venezuela and northern Guyana covering the large and shifting Orinoco Delta. The vegetation is mostly permanently flooded rainforest. The ecoregion is relatively intact apart fro ...

, Guianan moist forests and Guianan freshwater swamp forests. The Guianan mangroves ecoregion is part of the Guianan-Amazon Mangroves global ecoregion, which also contains the Amapa mangroves, Pará mangroves and Maranhão mangroves ecoregions.

Physical

Elevations in the flat, narrow strip of coastal land covered by the mangroves range from sea level to about 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 in the Orinoco delta. The Oronoco river has an average flow of per second, and deposits 200,000 tons of sediment each year, resulting in a very unstable landscape.

Climate

There are considerable differences in climate along the length of the ecoregion. Annual rainfall varies from in Venezuela to the east of the Gulf of Paria to in parts of Suriname. Some areas have a four-month

dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The t ...

while others have none. In the Orinoco Delta the mean monthly temperature ranges from .

Flora

The composition of the mangrove forests depend on the soil and the salinity of the water. Mixed stands of Rhizophora and

Avicennia ''Avicennia'' is a genus of flowering plants currently placed in the bear's breeches family, Acanthaceae. It contains mangrove trees, which occur in the intertidal zones of estuarine areas and are characterized by its "pencil roots", which ar ...

species are found in areas of higher salinity, particularly in the extreme northwest. Rhizophora and Laguncularia species grow in channels with more fresh water, and Rhizophora, Avicennia and Laguncularia grow where the soil contains more organic matter. The higher zones hold forests dominated by Avicennia species while herbaceous vegetation grows in the more saline swamps. There are diverse habitats in the Orinoco delta. The most saline parts have formations of ''

Rhizophora mangle ''Rhizophora mangle'', also known as the red mangrove, is a salt-tolerant, small-to-medium sized evergreen tree restricted to coastal, estuarine ecosystems along the southern portions of North America, the Caribbean as well as Central America ...

'', '' Rhizophora harrisonii'' and '' Rhizophora racemosa''. In less saline areas further inland Rhizophora species and the palm ''

Mauritia flexuosa ''Mauritia flexuosa'', known as the moriche palm, ''ité'' palm, ''ita'', ''buriti'', ''muriti'', ''miriti'' (Brazil), ''canangucho'' (Colombia), ''morete or acho'' (Ecuador), ''palma real'' (Bolivia), or ''aguaje'' (Peru), is a Arecaceae, palm t ...

'' grow together in peat bogs. In other parts of the delta the Rhizophora species mingle with swamp forest species such as ''

Pterocarpus officinalis ''Pterocarpus officinalis'', the dragonsblood tree, is a species of flowering plant in the family Fabaceae, native to southern Mexico, Central America, the Caribbean, and northern South America. It is typically found in coastal freshwater or slig ...

'', '' Symphonia globulifera'',

açaí palm The açaí palm (, , from Nheengatu ''asai''), '' Euterpe oleracea'', is a species of palm tree (Arecaceae) cultivated for its fruit (açaí berries, or simply açaí), hearts of palm (a vegetable), leaves, and trunk wood. Global demand for th ...

(''Euterpe oleracea'') and

Roystonea ''Roystonea'' is a genus of eleven species of monoecious Arecaceae, palms, native to the Neotropical realm, Neotropics, in the Caribbean, the adjacent coasts of Florida in the United States, Mexico, Central America and northern South America. Co ...

species. There are wide belts of Rhizophora in the inner estuary, with

on higher ground, sometimes mixed with ''Pterocarpus officinalis'', ''Symphonia globulifera'' and

Vitex ''Vitex'' is a genus of flowering plants in the sage family Lamiaceae. It has about 250 species.Raymond M. Harley, Sandy Atkins, Andrey L. Budantsev, Philip D. Cantino, Barry J. Conn, Renée J. Grayer, Madeline M. Harley, Rogier P.J. de Kok, Tat ...

species.

Along the coast from eastern Venezuela to the Guyanas the mangroves form belts a few meters wide associated with deciduous forests, muddy meadows and muddy forests in flooded areas. Dominant species include '' Costus arabicus'', '' Cyperus giganteus'', '' Eichhornia crassipes'', '' Heliconia psittacorum'', ''

Roystonea regia ''Roystonea regia'', commonly known as the royal palm, Cuban royal palm, or Florida royal palm, is a species of Arecaceae, palm native to Mexico, the Caribbean, Florida, and parts of Central America. A large and attractive palm, it has been plan ...

'' and ''

''. Muddy forests on ground that is almost always flooded have a single dense stratum of trees with heights from such as ''Pterocarpus officinalis'', ''Symphonia globulifera'', '' Tabebuia aquatilis'', açaí palm (''Euterpe oleracea''), Manicaria species and ''

''. The mangrove belts hold ''

Laguncularia racemosa ''Laguncularia'' is a genus of plants in the family Combretaceae. The only species in the genus is ''Laguncularia racemosa'', the white mangrove. It is native to the coasts of western Africa from Senegal to Cameroon, the Atlantic Coast of the Am ...

'' on the seaward side, mixed with

Spartina ''Spartina'' is a genus of plants in the grass family, frequently found in coastal salt marshes. Species in this genus are commonly known as cordgrass or cord-grass, and are native to the coasts of the Atlantic Ocean in western and southern Eu ...

species of salt marsh grass, in front of stands of ''

Avicennia germinans ''Avicennia germinans'', the black mangrove, is a shrub or small tree growing up to 12 meters (39 feet) in the acanthus family, Acanthaceae. It grows in tropical and subtropical regions of the Americas, on both the Atlantic and Pacific Coasts ...

''.

Fauna

The ecoregion has diverse fauna. It is the largest area in South America where migrating shorebirds from the

Nearctic realm The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America t ...

spend the winter, with up to 5 million birds visiting in one year. Over 118 species of birds have been recorded in Suriname and Venezuela, of which more than 70 are waterbirds. Bird species include

scarlet ibis The scarlet ibis, sometimes called red ibis (''Eudocimus ruber''), is a species of ibis in the bird family Threskiornithidae. It inhabits tropical South America and part of the Caribbean. In form, it resembles most of the other twenty-seven ex ...

(''Eudocimus ruber''),

black skimmer The black skimmer (''Rynchops niger'') is a tern-like seabird, one of three similar bird species in the Rynchops, skimmer genus ''Rynchops'' in the gull family Laridae. It breeds in North America, North and South America. Northern populations bir ...

(''Rynchops niger''), gull-billed tern (''Gelochelidon nilotica''), short-billed dowitcher (''Limnodromus griseus''),

lesser yellowlegs The lesser yellowlegs (''Tringa flavipes'') is a medium-sized shorebird. It breeds in the boreal forest region of North America. Taxonomy The lesser yellowlegs was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in ...

(''Tringa flavipes''), greater yellowlegs (''Tringa melanoleuca''),

black-bellied whistling duck The black-bellied whistling duck (''Dendrocygna autumnalis''), formerly called the black-bellied tree duck, is a whistling duck that before 2000 bred mainly in the southernmost United States, Mexico, and tropical Central America, Central to sout ...

(''Dendrocygna autumnalis'') and tricolored heron (''Egretta tricolor''). More than 50 species of mammals have been recorded, including

opossum Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North A ...

bat Bats are flying mammals of the order Chiroptera (). With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most birds, flying with their very long spread-out ...

s, tufted capuchin (''Sapajus apella''),

common squirrel monkey Common squirrel monkey is the traditional common name for several small squirrel monkey species native to the tropical areas of South America. The term common squirrel monkey had been used as the common name for ''Saimiri sciureus'' before gene ...

(''Saimiri sciureus''), Venezuelan red howler (''Alouatta seniculus''),

white-faced saki The white-faced saki (''Pithecia pithecia''), is a species of New World saki monkey. The small bodied neotropical primate can be found in Brazil, French Guiana, Guyana, Suriname, and Venezuela. This species feeds mostly on fruits, nuts, seeds, ...

(''Pithecia pithecia''),

giant anteater The giant anteater (''Myrmecophaga tridactyla'') is an Insectivore, insectivorous mammal native to Central America, Central and South America. It is the largest of the four living species of anteaters, which are classified with sloths in the or ...

(''Myrmecophaga tridactyla''),

jaguar The jaguar (''Panthera onca'') is a large felidae, cat species and the only extant taxon, living member of the genus ''Panthera'' that is native to the Americas. With a body length of up to and a weight of up to , it is the biggest cat spe ...

(''Panthera onca''),

cougar The cougar (''Puma concolor'') (, ''Help:Pronunciation respelling key, KOO-gər''), also called puma, mountain lion, catamount and panther is a large small cat native to the Americas. It inhabits North America, North, Central America, Cent ...

(''Puma concolor''),

ocelot The ocelot (''Leopardus pardalis'') is a medium-sized spotted Felidae, wild cat that reaches at the shoulders and weighs between on average. It is native to the southwestern United States, Mexico, Central America, Central and South America, ...

(''Leopardus pardalis'') and

capybara The capybara or greater capybara (''Hydrochoerus hydrochaeris'') is the largest living rodent, native to South America. It is a member of the genus '' Hydrochoerus''. The only other extant member is the lesser capybara (''Hydrochoerus isthmi ...

(''Hydrochoerus hydrochaeris''). The paradoxal frog ('' Pseudis paradoxa'') and the common Suriname toad (''Pipa pipa'') have adapted to the saline conditions. Reptiles include

olive ridley sea turtle The olive ridley sea turtle (''Lepidochelys olivacea''), also known commonly as the Pacific ridley sea turtle, is a species of turtle in the family Cheloniidae. The species is the second-smallest and most abundant of all sea turtles found in t ...

(''Lepidochelys olivacea''), which nests on the beaches,

green iguana The green iguana (''Iguana iguana''), also known as the American iguana or the common green iguana, is a large, arboreal, mostly Herbivory, herbivorous species of lizard of the genus ''Iguana''. Usually, this animal is simply called the iguana. ...

(''Iguana iguana''), spectacled caiman (''Caiman crocodilus'') and

green anaconda The green anaconda (''Eunectes murinus''), also known as the giant anaconda, emerald anaconda, common anaconda, common water boa, or southern green anaconda, is a semi-aquatic boa species found in South America and the Caribbean island of Trin ...

(''Eunectes murinus'').

Status

The

World Wildlife Fund The World Wide Fund for Nature (WWF) is a Swiss-based international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the ...

gives the ecoregion the status of "Relatively Stable/Intact". There are many protected areas, and large sections of mangroves are intact. Suriname has at least seven protected areas, most with a degree of connectivity, including the Coppename Monding wetland and the Wia-Wia nature reserve. Venezuela has the Mariusa National Park and the Orinoco Delta Biosphere Reserve. The Guarapiche Forest Reserve in the San Juan delta holds a patch of mangroves, palms and swamp forests. Agriculture such as rice cultivation has caused some fragmentation, but most fragmentation is natural. The main threats come from logging to obtain building material, fuel, tannin and medicinal products. Upstream agriculture releases fertilizers and pesticides, and adds sediments due to erosion. Population growth and tourism are increasing use of the mangroves as a source of food such as shrimp and wildlife, or for grazing domestic animals. Unsuccessful hydraulic engineering has damaged the Orinoco delta environment, and oil prospecting is a concern.

References

Sources

* * * {{DEFAULTSORT:Guianan mangroves Ecoregions of Venezuela Mangrove ecoregions Neotropical ecoregions Amazon biome