Location and General Description
This ecoregion, located in northern Colombia, is a unique ecosystem, comparable to the Amazonian. The main river is the Magdalena, but others of importance are the Cauca, Nechí, San Jorge, Sinú and Atrato. For some authors it is an extension of the Chocó but it has its own identity and endemic species. The Ecoregion is bordered by the Eastern and Central cordilleras in the Middle Magdalena, or Magdalena Medio, and extends itself westwards to the Urabá – Chocó, bordering the northern extremes of the Central and Western cordilleras and includes the watersheds of the Lower Cauca, the Nechí, the San Jorge, the Sinú and the lower Atrato rivers. Its location is between 5° 30’ N and 9° N, and between 73° 30’ W and 77° W, westwards after 7° 30’ N.
The climate of the region is seasonal, being wetter towards the centralarea, around the Serranía de San Lucas and in the upper reaches and canyons of the Sinú, San Jorge and Nechí. The dry times are between January and March, and July-August. During the longest dry spell, at the beginning of the year, the strong winds from the Caribbean Sea sweeps all the clouds towards the northern extreme of the Andean Central and Western Cordilleras, which form a series of Serranías called Abibe, San Jerónimo, Ayapel and de San Lucas. But during the rainy season, the rains are heavy; more than 4,000 mm per year in the canyons and up-rivers. The mean rainfall in the low jungles is around 3,000 mm per year. All this wetness is drained back through these large rivers and towards the Caribbean Sea, but before, forming a huge system of wetlands, lagoons, marshes and ponds of tremendous importance for wildlife, both native and migratory, because is in this wetlands and jungles where most of the population of many species of ducks, raptors, flycatchers and other song-birds spend the northern winter months.
The landscape is highly variable, with a topography mainly flat or undulating, it also has several serranías and isolated mountains of considerable size. The most noteworthy is the Serranía de San Lucas, very little known in terms of its biological richness, reaches heights of more than 2.600 masl. But of equal importance are the other serranías, especially Abibe, which form a natural boundary and at the same time, the link between the Chocó and Darién with central and North America, and also with South America, the Andes and the Amazon. At the center of the region there are the flat lands, where most of the water is stored in the ciénagas or wetlands.
The general vegetation is of dense and high jungles on drier soils, and palmettos and wetland vegetation on flooded soils. The diversity of the trees and plant life in general, is enormous, being dominant large trees such as Caryniana pyriformis, Caryocar glabrum, Caryocar amygdaliferum, Miroxylon balsamum, Ochroma lagopus, Anacardium excelsum ,Hymenea courbaril, Schyzolobium parahybum, Ceiba pentandra, Cedrela odorata, Tabebuia rosea, Cordia gerascanthus and many more. Many palm species, and a rich and diverse under story is a characteristic of these jungles. Beautiful orchids such as the endemic giant Cattleya, Cattleya warscewiczii, or the Butterfly orchid Psychopsis papilio, or the Swan orchid Cycnoches chlorochilon or the Holly Spirit orchid Peristeria elata are native to this ecosystem.
Vines of the largest size, creepers, aroids and bromeliads and more than 150 orchid species are part of the epiphytic realm that grows over the giant trees. Endemic to the region are Heliconia rigida, H. lentiginosa, H. laxa and H. sanctae-theresae.
The Magdalena-Urabá moist forests are unique in terms of biodiversity and endemism; due to its location, these jungles are the link or bridge between the northern ecoregions of Mesoamerica and the Chocó with the Andean and Amazonian ecoregions. Not only it gets the influence of these regions but also has its distinctive features, as a high degree of endemism and very high species diversity; it is also the place of arrival of many migratory bird species from the north and the wetlands are the nursery for many important fish species, both fresh and salt-water.
Several large mammals inhabit this region, both the jungles or the wetlands; among them are the Colombian tapir (Tapirus terrestris colombianus), the manatee (Trichechus manatus), the capybara (Hydrochaeris hydrochaeris), the jaguar (Panthera onca), the spider monkey (Ateles geoffroyi), the cotton-top tamarin (Saguinus oedipus), the silvery-brown bare-face tamarin (Saguinus leucopus), the cougar (Puma concolor), the brocket deers (Mazama americana), and M. gouazoubira, the ocelot (Leopardus pardalis), the jaguaroundi (Herpailurus yagouaroundi), the crab-eating raccoon (Procyon cancrivorus) and the giant anteater (Myrmecophaga tridactyla) as the most endangered.
Very rich in bird species, and the most important winter habitat for waterfowl and birds of prey such as Anas discors, A. cyanoptera, A. acuta, A. clypeata and A. americana, and the osprey Pandion haliaethus. Several bird species native to the region are the screamer Chauna chavarria, the wild muscovy duck Cairina moschata, the comb duck Sarkidiornis melanotos, the tree or whistling ducks Dendrocygna autumnalis, D. viduata and D. bicolor. The powerful eagles Spizaetus tyrannus, Morphnus guianensis and Harpia harpyja, the critically endangered blue knobbed curassow Crax alberti, six species of macaws Ara ambigua, A. militaris, A. ararauna, A. macao, A. chloroptera and A. severa, among others.
Among the reptiles, the crocodile Crocodylus acutus and the giant river turtle Podocnemis lewyana are critically endangered; more common are the bushmaster snake Lachesis muta, the caiman Caiman sclerops, the iguana Iguana iguana, the boa Boa constrictor, the tortoise Geochelone carbonaria and the lizard Tupinambis nigropunctatus.
Several areas of considerable size still intact and with little human intervention; around the Serranía de San Lucas is the largest patch. But the conditions and fragmentation of the ecoregion are diverse, depending of the location.
There are many official figures of conservation in this important region; there is not a National Park or alike; several project with international funds are aimed to rescue some important wetlands, and the establishment of private nature reserves is starting with strong forces in some areas.
Types and Severity of Threats
The region is surrounded by most of the Colombian population and the pressure for the natural resources are tremendous; large scale colonization, cattle ranching, gold mining, oil drilling, valuable timber, narcotic crops and warfare, together with the extreme pollution of the two most important rivers, the Magdalena and the Cauca, are putting tremendous pressure on these fragile and unique ecosystems.
Justification of Ecoregion Delineation
These moist forest are bound by the northern Andes and by xeric formations. The southern linework follows the Cordillera Occidental and Cordillera Central where it abuts to montane forest on an elevational delineation, and this ecoregion extends up both the Cauca and Magdalena Valleys, where it abut to dry forest habitats. The eastern linework follows the elevational delineation of the montane forest of the Cordillera Oriental, from the Magdalena Valley northwards to the dry forests of the Sinú Valley, where there is a marked distinction in climate and species assemblages. Eastern delineation’s similarly follow the Cordillera Occidental northwards, at which point we distinguish this from the Chocó forests of the Pacific catchment, and finally follows the coast of the Caribbean. Northern limits of this ecoregion are the xeric habitats of the Guajira area and dry forests of the Sinú Valley. Montane and xeric barriers have isolated this ecoregion, and its proximity to the isthmus of Central America has created distinct species assemblages and many endemic species. Final linework was completed by regional experts and a workshop on ecoregion of the Northern Andes (Bogota, Colombia, 24-26, July, 2000).
Complejo Ecoregional de los Andes del Norte (CEAN). Experts and ecoregional priority setting workshop. Bogota, Colombia, 24-26, July, 2000.
Hernandez -Camacho, J. et al. 1992; Unidades Biogeográficas de Colombia; Gonzalo Halffter, editor, Acta Zoológica Mexicana, CYTED-D, México
Hernández – Camacho, J. et al. 1992; in La Diversidad Biológica de Iberoamérica; Gonzalo Halffter, editor, Acta Zoológica Mexicana, CYTED-D, México.
Prepared by: Emilio Constantino
Reviewed by: In process