Orinoco Delta and Eastern Guyana Highlands

Map of the Month: Orinoco Delta and Eastern Guyana Highlands

Map boundaries: 0 to 10 degrees North; 56 to 64 degrees West

Countries (States, Regions, or Districts): Brazil (Amazonas, Para, and Roraima), Guyana, Suriname (Coronie, Nickerie, and Sipaliwini), and Venezuela (Amazonas, Anzoategui, Bolivar, Delta Amacuro, and Monagas).

Overview

This map area extends from the Venezuelan coast range in the northwest to the Amazon rainforest in the south. Although the region is mostly tropical moist forest, there are areas of xeric vegetation in the northwest. Grasslands and savannas are found in the lower Orinoco and southwestern Suriname, and in La Gran Sabana where Brazil, Guyana, and Venezuela come together. In the Orinoco Delta and along the coast of Suriname are swamp forests that mark the transition from coastal mangroves to higher elevation tropical forests. The Guyana Highlands are notable for the tepuys, which are about 100 dramatic flat-topped sandstone mountains scattered across Venezuela, northern Brazil, central Guyana, and central Suriname. The most well-known tepuy is Auyan in southeastern Venezuela, from which Angel Falls plunges.

This map area includes Guri Reservoir, an artificial lake in Bolivar state, Venezuela. An archipelago of hilltop islands was created by the filling of the lake. Since 1993, ecologists have studied the islands in the Connecticut-sized reservoir. From an ecological standpoint, the islands were not big enough to support large predators like jaguars, army ants, and armadillos. With the predators gone, other animals and plants took over, causing major ecological changes. For example, freed from army ants and armadillos, fungus-eating ants of the genus Atta took over, deforesting trees and allowing thorny vines to grow. The end point was a treeless island with a tangle of liana (vine) stems. Howler monkeys initially experienced a population explosion, but then ended up starving as defoliated trees began growing increasingly poisonous vegetation in defense. Based on these results, conservation scientists should focus on replacing top predators, or at least devise management interventions to substitute for the loss of the key species (Stolzenburg, 2008).

Ecoregions and Provinces/Political Subdivisions

Tropical and Subtropical Moist Broadleaf Forests

NT 117, Cordillera La Costa montane forests. Found in Monagas State, Venezuela. Evergreen moist forests on mountain tops. Gyranthera, Trophis, and Ficus at lower elevations, then evergreen montane cloud forests, then elfin forest and scrub at the mountain tops.

NT 124, Guyanan Highlands moist forests. Found in Brazil—Amazonas and Roraima; and Venezuela—Amazonas and Bolivar. Tall primary rainforest and savannas. Emergent rainforest trees are Calophyllum, Anacardium, and Manilkara.

NT 125, Guyanan moist forests. Found in Brazil—Roraima; Guyana—Barima-Waini, Cuyuni-Mazaruni, Demerara-Mahaica, East Berbice-Corentyne, Essequibo Islands-West Demerara, Mahaica-Berbile, Pomeroon-Supenaam, Potari-Siparuni, Upper Demerara-Upper Berbice, Upper Takutu-Upper Essequibo; Suriname—Coronie, Nickerie, and Sipaliwini; and Venezuela—Bolivar and Delta Amacuro. Tropical lowland forest and savannas. Bignoniaceae, Bobacaceae, Euphorbaceae trees and Calophyllum, Carapa, and Ceiba.

NT 143, Negro-Branco moist forests. Found in Brazil—Amazonas. Forested lowland plains and low sandstone table mountains. Notable plants are Virolia, Duckeanthus, Heteropetalum, and Leopoldina.

NT 147, Orinoco Delta swamp forests. Found in Guyana--Barima-Waini and Venezuela—Delta Amacuro and Monagas. Moist forests and wetlands with typical genera Carapa, Ceiba, and Dimorphandra.

NT 149, Paramaribo swamp forests. Found in Suriname—Coronie and Nickerie. A thin strip of flooded forests between mangroves and coastal mountains containing a mosaic of freshwater swamp habitats. Typical genera are Viriola, Symphonia, Euterpe, Crudia, and Macrolobium.

NT 158, Rio Negro capinarana. Found in Brazil—Amazonas and Roraima. Heath forests at the transition between the Guyana shield and Amazon basin. Savanna and thorn forests of cycads, Vochisia, Virola, Compsoneura, and Macrolobium grow on low nutrient soils.

NT 169, Tepuys. Found in Brazil—Roraima; Guyana—Cuyuni-Mazaruni, Potari-Siparuni, and Upper Takutu-Upper Essequibo; Suriname—Sipaliwini; and Venezuela—Amazonas and Bolivar. Isolated mountains with dramatic cliffs rising out of the rainforests. Various vegetation zones of montane shrublands, meadows, rock communities, and forests of Clusia, Monorobea, Miconia, and Graffenrieda.

NT 173, Uatuma-Trombetas moist forests. Found in Brazil—Amazonas, Para, and Roraima. A region of blackwater rivers north of the Amazon River in eastern Brazil. Typical plant famililies are Sapotaceae, Lecythidaceae, Bursuraceae, and Fabaceae.

Tropical and Subtropical Grasslands, Savannas and Shrublands

NT 707, Guyanan savanna. Found in Brazil—Para and Roraima; Guyana—Cuyuni-Mazaruni, Upper Takutu-Upper Essequibo; Suriname—Sipaliwini; and Venezuela—Bolivar. Located between the Amazon and Orinoco basins. Grass, shrubs, trees and forest islands, including the Gran Sabana of Venezuela. Impermeable subsoil and sandy soils are typical. Typical plant genera are Euphorbia, Humiria, and Clusia.

NT 709, Llanos. Found in Venezuela—Anzoategui, Bolivar, and Monagas. This is a transition area between the coastal xeric habitats of the Caribbean coast and the Amazon moist forests. Savannas are found in both seasonally flooded and non-flooded areas.

Flooded Grasslands and Savannas

NT 906, Orinoco wetlands. Found in Venezuela—Delta Amacuro and Monagas. Flooded grasslands and forests, buffered by mangroves.

Deserts and Xeric Shrublands

NT 1309, La Costa xeric shrublands. Found in Venezuela—Anzoategui and Monagas. Sparse dry desert shrubs, including Cactaceae, Leguminosae, and Capparidaceae.

Mangrove

NT 1411, Guyanan mangroves. Found in Guyana—Barima-Waini and Pomeroon-Supenaam; Suriname—Coronie and Nickerie; and Venezuela—Delta Amacuro and Monagas.

Freshwater Ecoregions of the World

South America Region

Tropical and Subtropical Upland Rivers

308. Orinoco Guiana Shield.

310. Essequibo

311. Guianas

315. Amazonas Guiana Shield

Tropical and Subtropical Floodplain Rivers and Wetland Complexes

307. Orinoco Llanos.

314. Rio Negro

Large River Deltas

309. Orinoco Delta and Coastal Drainages. As the Orinoco reaches the coast, the main river channel divides into a network of smaller channels.

Marine Ecoregions of the World

Tropical Atlantic Realm, North Brazil Shelf

71. Guianan

UNESCO World Heritage Sites

Central Suriname Nature Reserve. A pristine montane and lowland rain forest with 5000 vascular plants. Significant vertical relief and soil diversity in the watershed of the Coppename River. Contains Tafelberg Tepui. Found in Sipaliwini District of Suriname. Ecoregion 125, Guyanan moist forest.

Canaima National Park. An area of 100 tepuis, savannas, and waterfalls. The top of Auyan Tepui is an intricate maze of jagged sandstone with holes and caves. Includes 3211-foot-high Angel Falls, reached from Canaima, Venezuela, and Gran Sabana, reached by highway from Guayana City in Venezuela. Found in Bolivar State, Venezuela. Ecoregions 124 (Guyanan Highlands moist forests), 169 (Tepuis), and 707 (Guyanan savannas).

Other points of interest

Amazonas National Forest. Found in Brazil--Roraima. Ecoregion 124.

Anaua National Forest. Found in Brazil—Roraima. Ecoregion 158.

Bakhuys Mountains. An important bird area with crested eagle, harpy eagle,a nd blue-cheeked parrot. Found in Sipaliwini District, Suriname. Ecoregion 125.

Bigi Pan. Mudflat and swamp area with Guyanian Piculet, Blood-Colored Woodpecker, and Rufous Crabhawk. Found in Nickerie District, Suriname. Ecoregion 1411 (mangroves)

Blanche Marie Falls. Located in Sipalawini District, Suriname. Ecoregion 125.

Caracarai Ecological Station. Found in Roraima, Brazil. Ecoregion 707.

Caruachi. An important bird area on the Guri Resevoir. Found in Bolivar State, Venezuela. Ecoregion 709, Llanos.

Coppename Estuary National Park. Noted for bird colonies. Located in Coronie District, Suriname. Ecoregion 1411 (mangroves).

Delta del Orinoco National Park. Swamps and marshes of mangroves, palms, grasslands. Found in Delta Amacuro, Venezuela. Ecoregion 147 and 1411.

Gran Morichal Wildlife Refuge. Savanna with scattered trees and palms. Found in Delta Amacuro and Monagas, Venezuela. Ecoregion 906.

Guayana (city). Noted for waterfalls upstream on Caroni River. Found in Bolivar state, Venezuela. Ecoregions 125 (Guyanan moist forest) and 709 (Llanos).

Guaiquinima tepui. Tepui topped by evergreen rainforest. Found in Bolivar State, Venezuela. Ecoregion 124 (Guyana highlands moist forest) and 169 (tepuis).

Imateca Reserve. Hills of Guyana Shield; preserves evergreen rainforest. Found in Bolivar and Delta Amacura, Venezuela. Ecoregion 125 and 147.

Iwokrama Rainforest Programme. A research area with canopy walkway and hikes to mountains and petroglyphs. Located in Potari-Siparuni Region of Guyana. Ecoregion 125.

Jonestown (site). In 1978, the American cult known as the Peoples Temple committed mass suicide. The site was located southwest of Kaituma in Barima-Waini Region of Cooperative Republic of Guyana. Ecoregion 125.

Kabalebo/Arepahu. An important bird area by the Kabalebo River, noted for green ibis. Found in Sipaliwini District, Suriname. Ecoregion 125.

Kaieteur National Park. Unspoiled forest and a 100-meter waterfall five times the height of Niagara. Located in Potari-Siparuni Region of Guyana.

Maraca Ecological Station. Found in Brazil—Roraima. Ecoregion 124.

Niquia Ecological Station. Found in Roraima, Brazil. Ecoregion 158.

Nort Coronie. Important bird area and mudflats. Found in Coronie District, Suriname. Ecoregion 1411 (Mangroves).

Northwest Suriname (NWS on map). An area of grass swamps and swamp forests harboring the giant river otter and manatees. Found in Nickerie District, Suriname. Ecoregion 149, Paramaribo swamp forests.

Orinduik Falls. Located in Potari-Siparuni Region of Guyana and Roraima State, Brazil. Ecoregion 125.

Pedernales-Capure. Found in Delta Amacuro, Venezuela. Ecoregion 1411.

Raleigh vallen/Voltzberg Nature Reserve. A subunit of the Central Suriname Nature Reserve on the Coppename River. Found in Sipaliwini District, Suriname. Ecoregion 125.

Roraima National Forest. Found in Roraima, Brazil. Ecoregion 124.

Monte Roraima National Park. Encompasses the Brazilian portions of Roraima Tepui. Found in Roraima, Brazil. Ecoregion 125 and 169.

Roraima Tepui. The highest of the tepuis, this mountain is at the meeting point of Brazil, Guyana, and Venezuela. It has a 400 m cliff of quartzite with a cloud forest of ferns and an open, rocky summit. It is reached by a 5-day trek. Ecoregion 169 (tepuis)

Rupununi Savanna. Dry grassland in southern Guyana. Located in Upper Takutu-Upper Essequibo Region of Guyana.

Serra da Mocidade National Park. Found in Roraima, Brazil. Ecoregion 124 and 158.

Shell Beach. A 145-km reach of coastline from Pomeroon River to Venezuelan border in Guyana. The nesting ground of sea turtles: leatherback, green, hawksbill, and olive ridley. Found in Pomeroon-Supenaam and Barima-Waini regions, Guyana. Ecoregion 1411.

Sipaliwini Nature Reserve. Contains the Sipaliwini savanna. Found in Sipaliwini District, Suriname. Ecoregion 707.

Tucupita. Base for excursions to Orinoco Delta and Warao villages at Guyana border. Found in Delta Amacuro State, Venezuela. Ecoregion 147.

Urutani tepui. Topped by an evergreen rainforest. Located in Bolivar State, Venezuela and Roraima State, Brazil. Ecoregion 169 (Tepuis).

Virua National Park. Found in Roraima, Brazil. Ecoregion 707.

References

Abell, Robin and 27 others. 2008. Freshwater Ecoregions of the World: A New Map of Biogeographic Units for Freshwater Biodiversity Conservation. Bioscience 58:403-414.

Emma Beare, ed. 2006. 501 Must-Visit Natural Wonders. Bounty Books.

Box, Ben. 2008. Footprint South American Handbook, 84^th edition.

BirdLife International. 2008. BirdLife’s Online World Bird Database. Accessed 29/12/2008 at http://www.birdlife.org/

Ildos, Angela S. and Bardelli, Giorgio G. 2001. Great National Parks of the World. AAA Publishing.

Olson, David M., et al., 2001. Terrestrial Ecoregions of the World: A New Map of Life on Earth. BioScience 51:933-938.

Schultz, Patricia. 2003. 1,000 Places to See Before You Die. Workman Publishing.

Riley, Laura and William. 2005. Nature’s Strongholds. Princeton University Press.

Spalding, Mark D. and 14 others. 2007. Marine Ecoregions of the World: A Bioregionalization of Coastal and Shelf Areas. Bioscience 57:573-583.

Stolzenburg, William. 2008. Ecosystems Unraveling. Conservation Magazine 9(1):21-25.

World Heritage List. Accessed 5/24/09 at whc.unesco.org/en/list

Madeira River Map of the Month

Map boundaries: 0 to 10 degrees South; 56 to 64 degrees West

Country: Brazil (Amazonas, Mato Grosso, Para, Rondonia, Roraima)

Overview

This map area encompasses the drainage area of the largest, fourth largest, and fifth largest river systems in the world. The coverage is of the central Amazon basin (largest), lower Madeira drainage (fourth largest), and the lower Negro drainage (fifth largest). The Amazon River is as much as six miles wide as far as 1,000 miles upriver from its mouth. The Negro and Urubu, both north of the Amazon, are considered blackwater rivers, and the Tapajos (southeast area of the map) and Trombetas (northeast area of the map) are considered clear water rivers. The Madeira and Purus (central and southwest parts of the map) are considered whitewater rivers.

The map area is entirely covered by tropical moist forest, although forest formations vary in the northwest and southeast of the map. The campinarana of the northwest are heath forests believed to be short and shrubby due to low nutrient soils rather than seasonal dryness. The Mato Grosso forests of the southeast are tropical dry forests transitional between the Amazon rainforests and cerrado of central Brazil.

Ecoregions and Provinces/Political Subdivisions

Tropical and Subtropical Moist Broadleaf Forests

NT 132, Japura-Solimoes-Negro moist forests. Found in Brazil—Amazonas. These non-flooded, “terra firme” forests are found on a lowland plateau south of Rio Negro and north of the Amazon. Common plant families are Leguminosae, Sapotaceae, Rubiaceae, Chrysobalanceae, Lauraceae, and Annonaceae.

NT 133, Jurua-Purus moist forests. Found in Brazil—Amazonas. Evergreen moist forests found between the Amazon and Purus rivers contain a high level of tree diversity and a center of diversity for the Sapotaceae plant family. The area is a uniform, flat plain.

NT 135, Madeira-Tapajos moist forests. Found in Brazil—Amazonas, Mato Grosso, Para, and Rondonia. This ecoregion covers a large area extending from the Amazon into southern Brazil (see Chiquitano and Pantanal map), and a range of elevations from near sea level to 4000 feet. Major rivers through the ecoregion include the Aripuana, Marmelos, Maues, and Canuma. Vegetation types include dense lowland rainforest, woodland savanna, grasslands and semi-deciduous forests. Hills along the Marmelos and Tapajos rivers contain rare tree species such as Huberodendron and dwarf rubber trees.

NT 140, Mato Grosso tropical dry forests. Found in Brazil—Amazonas, Mato Grosso, and Para. Savannas, gallery forests,a nd thickets mark the transition between the Amazon rainforests and the cerrado of central Brazil.

NT 141, Monte Alegre varzea. Found in Brazil—Amazonas, Para, Rondonia, and Roraima. Seasonally flooded forests are common along the floodplains of the central Amazon, Madeira, Uatuma, Manirora, Jiparana, Purus, Piorini, and Branco rivers. Virola, Calycophyllum and Euterpe are common genera of trees.

NT 143, Negro-Branco moist forests. Found in Brazil—Amazonas. Forested lowland plains and low sandstone table mountains north of Rio Negro. Notable plants are Virolia, Duckeanthus, Heteropetalum, and Leopoldina. Plant families not found in Amazonian forests are Humiriaceae, Rapateaceae, and Tepuianthaceae.

NT 156, Purus varzea. Found in Brazil—Amazonas. The floodplain forests found in the upper Amazon basin are richer in species diversity than the monte alegre varzea. Common tree genera are Carapa, Iryanthera, and Ceiba.

NT 157, Purus-Madeira moist forests. Found in Brazil—Amazonas and Rondonia. Moist forests between the Purus and Madeira rivers and south of the Amazon spread across a vast, nearly flat plain in the central region of the map. Many of the forests are seasonally inundated. This is an area of high diversity and endemism for the following plant families: Leguminosae, Sapotaceae, Lecythidaceae, Moraceae, Chrysobalanceae, Lauraceae, and Myristicaceae.

NT 158, Rio Negro capinarana. Found in Brazil—Amazonas and Roraima. Heath forests at the transition between the Guyana shield and Amazon basin, found on low nutrient soils. Indicator plants are Gaylussacia, Glycoxylon, and Mauritia. Savanna and thorn forests of cycads, Vochisia, Virola, Compsoneura, and Macrolobium grow on low nutrient soils.

NT 168, Tapajos-Xingu moist forests. Found in Brazil—Para. Evergreen tropical rain forests found on non-flooded land between the Tapajos and Xingu rivers in the eastern Amazon. Southern areas contain liana forests of Bignoniaceae species. Elsewhere, Brazil nut and mahogany trees are common. Zollernia, Theobroma, and Cordia trees reach their western limit at the Tapajos River.

NT 173, Uatuma-Trombetas moist forests. Found in Brazil—Amazonas, Para, and Roraima. A region of blackwater rivers north of the Amazon River in eastern Brazil. Typical plant famililies are Sapotaceae, Lecythidaceae, Bursuraceae, and Fabaceae.

Freshwater Ecoregions of the World

South America Region

Tropical and Subtropical Upland Rivers

315. Amazonas Guiana Shield. Found in Amazonas, Para, and Roraima

320. Tapajos-Juruena. Found in Amazonas, Mato Grosso, and Para

321. Madeira Brazilian Shield. Found in Amazonas, Mato Grosso, and Rondonia.

Tropical and Subtropical Floodplain Rivers and Wetland Complexes

314. Rio Negro. Found in Amazonas and Roraima

316. Amazonas Lowlands. Found in Amazonas and Para.

World Heritage Sites

Central Amazon Conservation Complex. Found in Amazonas, these four preserves, totaling 6 million ha contain samples of varzea, upland forests, lakes and river channels and are home to river dolphins, Amazonian manatee, and the largest array of electric fish in the world. Shown on the map are Jau National Park and Anavilhanas Ecological Station. Not shown on the map are the Mamairaua Sustainable Development Reserve and Amana Sustainable Development Reserve, both located to the west of Jau National Park. Ecoregions 132 and 156.

Other points of interest:

Abufari Biological Reserve. Found in Amazonas. Ecoregion 156.

Alta Floresta. Site for spotting rare birds, located in Mato Grosso, Ecoregion 135.

Amana National Forest. Found in Para. Ecoregion 135.

Amazonia National Park. Found in Para. Ecoregion 135.

Anavilhanas Ecological Station. Largest group of freshwater islands in the world, 60 miles northwest of Manaus. Found in Amazonas. Ecoregion 132.

Balata-Tufari National Forest. Found in Amazonas. Ecoregion 157.

Bom-Futuro National Forest. Found in Rondonia. Ecoregion 135.

Crepori National Forest. Found in Para. Ecoregion 168.

Humaita National Forest. Found in Amazonas. Ecoregion 135.

Itaituba National Forest. Found in Para. Ecoregion 168.

Jacunda National Forest. Found in Rondonia. Ecoregions 135 and 141.

Jamari National Forest. Found in Rondonia. Ecoregion 135.

Jaru Biological Reserve. Found in Mato Grosso and Rondonia. Ecoregion 135.

Jatuarana National Forest. Found in Amazonas. Ecoregion 135.

Jau National Park. Part of Central Amazon Conservation Complex. Found in Amazonas. Ecoregion 132.

Pau-Rosa National Forest. Found in Amazonas. Ecoregion 135.

Mamori. A lake east of Manaus known for pink and gray river dolphins. Found in Amazonas. Ecoregion 141.

Manaquiri. A lake southwest of Manaus, known for great egret and fish eagles. Found in Amazonas. Ecoregion 141.

Meeting of the waters. The light brown water of the Amazon meets the dark, acid water of the Negro near Manaus

Porto Velho. A municipal park preserves rainforest flora. Just upstream of town are the rapids of the Madeira River. Found in Rondonia. Ecoregion 141.

Presidente Figueiredo—More than 100 waterfalls on tributaries to Urubu River; caves west of Lake Balbina. Found in Amazonas. Ecoregion 173.

Rio Trombetas Biological Reserve. Found in Para. Ecoregion 173.

Serra do Cachimbo. In the southeast portion of the map area is a 700-m escarpment with endemic species that grow in droughty white sandy soils. Found in Para. Ecoregions 140 and 168.

Uaimiri Atroari Indigenous Area. Found in Amazonas and Roraima. The Indian reserve straddles the road for 120 km north of Manaus.

Uatuma Biological Reserve. Found in Amazonas. Ecoregion 173.

References

Abell, Robin and 27 others. 2008. Freshwater Ecoregions of the World: A New Map of Biogeographic Units for Freshwater Biodiversity Conservation. Bioscience 58:403-414.

Emma Beare, ed. 2006. 501 Must-Visit Natural Wonders. Bounty Books.

Box, Ben. 2008. Footprint South American Handbook, 84^th edition.

Eyewitness Travel Brazil. Dorling Kindersley Ltd., London, 2007.

Kricher, John. A Neotropical Companion, 2^nd edition. Princeton University Press, 1997.

Olson, David M., et al., 2001. Terrestrial Ecoregions of the World: A New Map of Life on Earth. BioScience 51:933-938.

Schultz, Patricia. 2003. 1,000 Places to See Before You Die. Workman Publishing.

World Heritage List. Accessed 5/24/09 at whc.unesco.org/en/list