Consisting of a series of lagoons, this ecoregion corresponds to the remains of an old marine channel that divided the island of Hispaniola (Dominican Republic and Haiti) into two paleoislands more than 5000 years ago. The largest lake in this ecoregion, Lake Enriquillo in the Dominican Republic is the largest and most hypersaline lake in all of the Antilles. It consists of a depression that is approximately 44 meters (m) below sea level, surrounded by thorny subtropical mountains and dry forests of great biological interest. This lake is home to the largest population of American crocodile (Crocodylus acutus), although currently its populations are at risk. It is also the habitat for the iguana cornuda (Cyclura cornuta), which is endemic to the island of Hispaniola and the iguana de Ricord (C. ricordi), the latter being at risk of extinction due to its limited distribution. In addition, it is a resting, feeding, and reproductive location for the flamenco (Phoenicopterus ruber) and many other species of migratory birds. There are also other smaller lakes near Enriquillo, with highly valuable biota, including the manatí in lake Saumatre and the island's endemic Hispaniolan slider (Trachemys decorata), particularly in lake Rincón .
Location and General Description
Lake Enriquillo in the southwestern section of the Dominican Republic is located at 18°30'N and 71°40'W, occupying the lowest part of the basin known as Hoya del Lago Enriquillo between the Neyba and Bahoruco ranges, and has geomorphological characteristics that are unique in the Caribbean region. It is the largest lake in the Caribbean; it is 35 meters (m) long and 12 m wide and has a maximum depth of 24 m. There are three islands on the lake: Cabritos Island, Islita, and Barbarita Island. The first is the largest island and is 12 kilometers (km) long and an average of 2 km wide. Water temperature in the lake varies from 23.9 to 29°C, salinity is twice that of the sea and its waters are sulfurous. Rocks in the zone are coral limestones and remains of mollusk shell because in past geological eras the ecoregion corresponded to the marine channel that divided the island of Hispaniola into two paleoislands. Annual precipitation in this ecoregion is between 400 and 500 millimeters (mm), representing one of the most arid areas on the island. The lake is fed by subterranean and surface influents, but its volume only increases significantly with the hurricanes, cyclones, and tropical storms that lash the island. In the Dominican Republic, other less important lakes with origins similar to those of Lake Enriquillo are Rincón Lagoon (Cristóbal or Cabral), Lake Caballero. Rincón Lagoon is 47 square kilometers (km2) and is the largest body of fresh water in the Dominican Republic. In Haiti, Saumatre Lagoon (Étang Saumatre or Lago Azuei) is the country's largest lake. It occupies another concavity 10 km west of Lake Enriquillo, separated from it by the Jimaní anticline. It covers an area of approximately 120 km2 and is located in the far east of the Cul-de-sac Valley. Another smaller lake on the Haitian coast and close to Saumatre is Trou Cayman, measuring approximately 15 km2.
The shores of Lake Enriquillo, as well as the three islands on the lake and the smaller lagoons, have dry subtropical forest and subtropical thorny mountain that is very valuable because it has some species with very restricted distributions. Vegetation consists primarily of bayahonda (Prosopis juliflora), cambrón (Acacia macracantha), guayacán (Guaiacum officinale), almácigo (Bursera simarouba), baitoa (Phyllostylon brasiliensis), and spiny shrubs (cactáceas) such as the guazábara (Cylindropuntia caribaea), cayucos (Pilosocereus polygonus), melón espinoso (Melocactus lemairei), alpargata (Opuntia moniliformes) and bombillito (Neomammillaria prolifera) . Common palm trees are the yarey (Copernicia berteroana) and the palma cacheo (Pseudophoenix vinifera). In the wetter areas the baría (Callophylum calaba), copey (Clusia rosea), mangle rojo (Rhizophora mangle), and mangle botón (Conocarpus erecta) predominate.
An inventory of the flora on Cabritos Island shows that there are 105 species of plants, primarily herbaceous (57 species), followed by trees, cactus, shrubs, and creepers. To be noted is the limited numbers of palm and epiphyte species. More than 10% of the species on Cabritos Island are endemic to Hispaniola or the ecoregion. This habitat of subtropical dry forest and subtropical thorny montane vegetation is of great interest due to the abundance of xerophytic vegetation on the island of Hispaniola.
Both land and aquatic fauna in this ecoregion are also of great biological value. In the wetter areas, we find amphibians like the "maco pempém" (Bufo marinus) and endemic "bufónido" (Pelthophryne guntheri). In drier areas, we find various reptiles, with two species of iguana (Cyclura spp.), 25 species of lizards (Anolis spp., Ameiva spp., Aristelliger cochranae, and others) and 13 species of snakes (Epicrates spp., Uromacer catesbyi, and others). Of the two iguana species, Cyclura ricordi is critically at risk of extinction and lives only in this lake, in the Jaragua National Park. Also to be noted is the largest snake on Hispaniola Island is the Alsophis anomalus, which is only found in two other areas with insular geography. Aquatic herpetofauna is represented by the American crocodile (Crocodylus acutus) and a turtle the Hispaniolan slider or "jicotea" (Trachemys decorata) endemic to the island; with its largest population in Lake Rincón. Current populations of American crocodile on the island of Hispaniola are only found on Lake Enriquillo, Manzanillo Bay, and Lake Saumatre (Haiti) and Lake Enriquillo has the largest natural population in the world (estimated population of 400). Aquatic fauna is also represented by tilapia and other fish.
Of the 35 species of land birds reported, the most representative are the broad-billed tody (Tordus subulatos), burrowing owl, "cucú" (Athene cunicularia), palm crow, "cao" (Corvus palmarum), and vervain hummingbird (Mellisuga minima). Of the 62 species of aquatic birds, many of them migratory, we mention the pink flamingoes (Phoenicopterus ruber), roseate spoonbill (Ajaia ajaja), green-backed heron (Butorides striatus), little blue heron (Egretta caerulea), tricoloured heron (Hydranassa tricolor) and Bahama pintail (Anas bahamensis). Land mammals are represented by the greater bulldog bat (Noctilio leporinus) and Mexican free-tailed bat (Tadarida brasiliensis). It is important to emphasize the presence of sea cows or manatees (Trichechus manatus) in Lake Saumatre.
This ecoregion is outstanding in regional terms, with a vulnerable conservation status and maximum conservation priority (I). There is sufficient taxonomic and geographic data on the ecoregion to implement an appropriate conservation strategy. The succulent vegetation endemic to this area is very vulnerable to human activities and is thus a plant community at risk.
There are three National Parks in the ecoregion with IUCN management category II, all of them on the Dominican Coast. In 1974, the Cabritos Island National Park was created with an area of 26 km2. In 1995, the Enriquillo Lake National Park was created with 320 km2, and in 1997 Rincón Lagoon's category was changed from Wildlife Refuge to National Park, increasing the protected area of the park to 240 km2.
Types and Severity of Threats
One of the most significant threats to Lake Enriquillo is its high salinity at certain times of year as a result of the diverting of freshwater by pipes emptying into the lake for use in the area's agriculture. Another threat, particularly to crocodiles, is indiscriminate hunting as well as altered habitat due to reduced vegetation. Also detrimental is the drilling of tubular wells in communities close to the lake, grazing of livestock, and gathering of firewood. The most pressing causes of the degradation of Lake Saumatre and its surroundings involve the inflow of human and animal waste, sediments coming from mountain rains, contamination from detergents and other chemicals and the burning of trees. Insular ecosystems are very fragile and once altered it is difficult for them to revert to their original state.
Additional Information on this Ecoregion
- For a shorter summary of this entry, see the WWF WildWorld profile of this ecoregion.
- Amezqueta, J., J.P. Pujas, L.E. Pérez, J. Alarcón, L. Valdez, and E. Bautista, 1987. Aspectos generales sobre el cocodrilo americano. Santo Domingo, República Dominicana.
- Caribbean Environmental Programme (CEP) 1996. Status of Protected Area Systems in the Wider Caribbean Region. CEP Technical Report No. 36
- Dinerstein, E., D.M. Olson, D.L. Graham., A.L. Webster, S.A. Primm, M.P. Bookbinder, and G. Ledec. 1995. A Conservation Assessment of the Terrestrial Ecoregions of Latin America and the Caribbean. The World Bank. ISBN: 0821332961
- DNP 1989. Los parques nacionales de la República Dominicana. Dirección Nacional de Parques, Santo Domingo, RD.
- Hartshorn, G., G. Antonini, and R. DuBois. 1981. La República Dominicana. Pefil ambiental del país. Un estudio de Campo. JRB Associates, Virginia, USA.
- Hernández, C. y J. Czerwenka, 1986. Contribuciones para un nuevo concepto de conservación en el área del Lago Enriquillo. Secretaría de Estado de Agricultura, Departamento de Vida Silvestre. Santo Domingo, R.D.
- IUCN, 1982. IUCN directory of Neotropical Protected Areas. ISBN: 0907567630
- Marcano, E. J., 1987. Flórula de la Isla Cabritos.
- Marcano, J. (n.d). Suroeste Dominicano.
- Moreta, A. n.d. El lago Enriquillo aumenta su caudal con el agua de los ciclones y tormentas tropicales que azotan el país. El Siglo.
- Narpier, R. n.d.. Flora, fauna y belleza del Lago Enriquillo. El Siglo.
- OAS. 1984. Écologie, Republique d'Haiti. Map 1:500,000. Organization of American States, Washington, D.C., USA
- Octave, F. 1999. Lake Azuei: An important resource in Haiti being wasted. Island beat: News from the Environmental Frontline of the Caribbean. The Panos Institute of the Caribbean.
- Oldfield, S. (comp.), 1997. Cactus and Suculent Plants. IUCN/SCC Cacuts and Succulent Specialist Group. Gland, Switzerland.
- Olson, D., E. Dinerstein, G. Castro, and E. Maravi. 1996. Identifying gaps in botanical infromation for biodiversity conservation in Latin America and the Caribbean. World Wildlife Fund, Washington, D.C., USA.
- SEA/DVS 1990. La diversidad biológica en la República Dominicana. Reporte preparado por el Departamento de Vida Silvestre para el Servicio de Cooperación Social-Técnica y WWF-US. Secretaría de Estado de Agricultura, SURENA/DVS, Santo Domingo, RD.
- SEA/DVS 1995. Mejoramiento de la Situación Ambiental en la Propuesta Reserva de Biosfera "Enriquillo", Tomo 2. Santo Domingo, R.D.
- Tasaico, H. 1967. Mapa ecologico de la Republica Dominicana. Unidad de Recursos Naturales de la Union Panamericana.
- UNEP-WCMC. Protected Areas Programme. Parks, Protected Areas, and World Heritage.
- Valdez, G. y M. Mateo. 1992. Sistema de áreas protegidas de la República Dominicana. Dirección Nacional de Parques, Santo Domingo, RD.
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