Guajira-Barranquilla xeric scrub
The Guajira/Barranquilla ecoregion along the Caribbean Sea in Venezuela and Colombia is a unique xerophytic area in the neotropics. Proposed as a bird center of endemism, this arid habitat is dominated by thorn scrub. Herpetofauna is particularly rich with sixty-six species including the endangered species Geochelone carbonaria, and Phrynops dahli. Two national parks protect what little intact habitat is left from agricultural development.
Location and General Description
The Guajira/Barranquilla xeric scrub is located in three enclaves along the Caribbean Sea. The largest enclave is located in the Guajira Peninsula, which is the northernmost point of South America, in both northwestern Venezuela and northeastern Colombia. The enclave extends south between the Sierra Nevada de Santa Marta and the Serrania de Perijá. The second and smallest of the three enclaves is located east of the Santa Marta Bay, in the north of the Magdalena department of Colombia. The third enclave is found in the north of the Cordoba, Sucre, Bolivar and Atlantico departments, along the Caribbean Sea. The largest city in the ecoregion is Barranquilla.
The altitude in this ecoregion ranges from 0 in the coastal area to 865 masl in the Serranía de Macuira. Precipitation ranges from 125 to 1000 millimeters (mm). In the Guajira Peninsula precipitation occurs from August to November, while in the rest of the ecoregion, precipitation occurs from May to November. The highest average temperature in the area is 32.7 degrees Celsius (oC), the median is 26 oC and the lowest is 19.6 oC. Landscape elements in this ecoregion consist of hills (Serranía de Macuira), lowlands (llanuras), and some rivers. The largest river is the Magdalena. There are also smaller rivers that originate in the Sierra Nevada de Santa Marta and make their way to the Caribbean Sea through this ecoregion, including the Guachaca, Buritaca, Don Diego, Palomino, Ancho, Dibulla and Corual.
Dominant vegetation in this ecoregion includes thorn trees and succulents. Among some of the plant communities, there are forests dominated by Lonchocarpus punctatus, along with other species such as Bunchosia odorata and Ayenia magna. There are also forests of Prosopis juliflora, Erythrina velutina and Clerodendron ternifolium. Other plant communities in the area show several associations of two dominant species. Some examples are associations of Stronium graveolens with Tabebuia billbergii, Haematoxylon brasiletto with Melochia tomentosa, Libidibia coriaria with Cordia curassavica, Bursera glabra with Castela erecta, Vitex cymosa with Libidibia coraria, Mimosa cabrera with Cordia curassavica, Bursera tomentosa with Bursera graveolens, and Castela erecta with Cercidium praecox.
The most common vegetation in the ecoregion includes Acacia glomerosa, Bourreria cumanensis, Bulnesia arborea, Caesalpinia coriniana, Copaifera venezolana, Croton sp., Gyrocarpus americanus, Hyptis sp., Jacquinia pungens, Malpighia glabra, Myrospermum frutescens, Opuntia caribaea, Pereskia guamacho, Piptadenia flava, Proposes juliflora, Ritterocereus griseus, and R. deficiens.
According to Rangel, et al., the area of the Guajira peninsula has a total of 468 species of plants, 255 genera and 109 families. The most diverse families are the Leguminosae (51), Asteraceae (36), Poaceae (24) and Euphorbiacea (18).
Reptiles in the Guajira include 34 species, representing 21 genera and 10 families. The most diverse families are the Colubridae, Iguanidae and Gymnophthalmidae. Iguana iguana is the most endangered species in the area. Amphibians include 32 species, representing 17 genera and 7 families. Leptodactylidae is the most diverse family. Endangered species include Geochelone carbonaria, and Phrynops dahli. The only endemic reptile in the area is Phrynops dahli.
Birds in Guajira include 180 species, representing 140 genera and 50 families. The most diverse families are the Tyrannidae and Fringillidae. The ecoregion has various endemic birds restricted to arid lowlands in the Guajira peninsula and northeastern Colombia. The endemic birds listed below have "least concern"; status; they include the pygmy swift (Tachornis furcata), buffy hummingbird (Leucippus fallax), chesnut piculet (Picumnus cinnamomeus), white-whiskered spinetail (Synallaxis candei), black-backed antshrike (Sakesphorus melanonotus), slender-billed tyrannulet (Inezia tenuirostris), tocuyo sparrow (Arremonops tocuyensis), and vermilion cardinal (Cardinalis phoeniceus).
The ecoregion has various subspecies of birds that Rangel et al. mentions as endemic to Guajirá. These subspecies are bare-eyed pigeon (Columba corensis jacquin), crested bobwhite (Colinus cristatus continentis), green-rumped parrotlet (Forpus passerinus viridissimus), red-billed parrot (Pionus sordidus ponsi), brown-throated parakeet (Aratinga pertinax aeruginosa), puffbird (Bucco ruficollis decolor), straight-billed woodcreeper (Xiphorhynchus picus paraguanae), straight-billed woodcreeper (Xiphorynchus picus picirostris), pale-breasted spinetail (Synallaxis albescens perpallida), red-crowned woodpecker (Melanerpes rublicapillus paraguanae), troupial (Icterus icterus ridgwayi), Orinocan saltator (Saltator orenocensis rufescens), buff-breasted wren (Thryothorus leucotis collinus),and russet-throated puffbird (Hypnelus rificollis decolor).
Endemic mammalian terrestrial species characteristic to this ecoregion, and to others in dry forests in Colombia and Venezuela, are opossum (Marmosa xerophila) and vesper mouse (Calomys hummelincki). Marmosa is very well adapted to dry habitats, and is found in deciduous forest, while the vesper mouse is mainly found in sandy grasslands. Other endemic mammals in the area include subspecies of cottontail rabbit (Sylvylagus floridanus nigronuchalis), white-tailed deer (Odocoileus virginiaus curassavicus), and opposum (Marmosa xerohylica).
Even though the dry climate in this region does not favor crops, the whole ecoregion has been effected by humans, principally through agriculture and grazing. The southernmost part of the Guajira peninsula has been severely altered by such activities.
There are two important protected areas in the region, Macuira National Park (IUCN Category II) and Tayrona National Park (IUCN Category II). Macuira Park is located in the northeastern side of the Guajira Peninsula. The park has an area of 25,000 hectares (ha.), and is part of the Serranía de Macuira, which is an "island" of dense vegetation different from the surrounding desert. The elevation of the Serranía is 500 masl. The most common species are Acacia farnesiana, Anacardium excelsum, Cardiospermum carindum, Cassia tora, Cephalocereus colombianus, Dodonea viscosa, Fagara sp., Genipa americana, Lemaireocereus griseus, Pristimera vernicosa, Ruperchtia ramiflora The Park has isolated populations of caiman (Caiman crocodylus), ocelot (Leopardus pardalis), margay (Leopardus wiedii), and primates of the genus Alouatta. There are 7 endemic subspecies of birds in the Park.
Tayrona National Park has an area of 150 square kilometers (km2). The Park consists of mangroves and xeric scrubs. The most common species are Capparis odoratissima and Pltymiscium plystachum. The Park has recorded appriximately 100 species of mammals, 200 birds, and 31 species of amphibians. Some of the mammals are jaguar (Felis onca), paca (Cuniculus paca), collared peccary (Tayassu tajacu), red howler monkey (Alouatta seniculus seniculus), and various species of Chiropterans.
Types and Severity of Threats
The entire area is heavily populated due to the extensive network of roads in the Atlantico department.
- The Guajira region has the largest coal mine and salt deposits in Venezuela. Exploitation of these resources may lead to more pollution in the area.
- Water pollution, caused by oil and coal industrial waste, has greatly affected the coastal area.
- The land is used primarily for agriculture and livestock. Sheep and goats are the main types of livestock on the Caribbean Sea side.
- Tayrona National Park is affected by two activities: grazing and shipping coal from ports inside the Park's borders.
Justification of Ecoregion Delineation
This xeric scrub ecoregion covers most of the Guajira Peninsula of Colombia, extending eastwards into the Maracaibo Basin of Venezuela, and occurs to the west in coastal patches of various size near Barranquilla. A strip also extends southwards between the Santa Marta Mountains and the northern-most extension of the Andes (Serrania de Perijá). Northern limits are bound by the Caribbean Sea and western limits by the Gulf of Maracaibo. Linework for portions in Venezuela follow Huber and Alarcon, who classify this vegetation type as "spiny xeric shrublands". In Colombia, linework "for the Guajira Peninsula follows the United Nations Educational, Scientific, and Cultural Organization (UNESCO) classifications of "subdesert deciduous shrubland with succulents" and "subdesert deciduoud shrubland without succulents".
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