Location and General Description
Located along the Atlantic Ocean coastline beginning just inside Nicaragua then extending to the border of Coata Rica and Panama (Olson et al. 1996). The sparseness of mangroves in this ecoregion is a result of the high inflow of freshwaters to the coastline ocean zone of this ecoregion. Among the highest rates of rainfall in the world, this ecoregion recieves over 6 m a year at the Nicaragua and Costa Rica Border. Peak rainfall occurs in the warmest months between May and September. A relatively dry season occurs from January to April, which coincides with stronger trade winds. Tides are semi-diurnal and have a range of less than 1/2 meter. The sparseness of mangrove patches is also why little information is available for Atlantic coast mangroves in these two countries, and little has been published that directly references mangroves in this ecoregion.
The area is disturbed at least once in a century by hurricanes, which may result in a die-off of all mangroves, as occurred in 1988 as a result of Hurricane Joan, though they do regenerate. This keeps the mangroves relatively young and small in stature, and that is also why they tend to be found in even-age stands (Roth 1997).
The offshore sea grass beds, which are among the most extensive in the world, are a source of food and refuge for endangered green sea turtles (Chelonia mydas). Mangroves play an important role in trapping sediments from land that are detrimental to the development of both coral reefs and sea grasses that are associated with them. Mangrove species including Rhizopora mangle, Avicennia germinans, Laguncularia racemosa, Conocarpus erecta and R. harrisonii grow alone the salinity gradient in appropriate areas. Rare occurrences of Pelliciera rhizophorae and other plant species associated with mangroves include the leather fern Acrostichum sp, which also invades cutover mangrove stands and provides some protection against erosion. In this particular ecoregion, the mangroves are associated with the freshwater palm species Raphia taedigera. Other mangrove associated species are Pachira acuatica and Pterocarpus officinalis.
The area of Costa Rica near the Nicaraguan border is considered to be the most species rich in Costa Rica. Although not restricted to mangroves, incomplete census studies of wildlife conducted at a local biological station report 120 species of mammals, over 300 bird species and more than 100 species of reptiles and amphibians have been documented. Of the sixteen species of endangered mammals known in Costa Rica, thirteen were found in this survey. Six of the seven nationally endangered reptiles occur in the ecoregion.
Threatened species found in the region such as crocodile (Crocodylus acutus), tapir (Tapirus bairdii), marine turtles (Chelonia mydas), Dermochelys coriacea, and the manatee (Trichecus manatus). Mammal species found in this highly diverse ecoregion include pacas (Agouti paca), primates such as black mantled howler monkey (Alouatta palliata), Geoffrey's spider monkey (Ateles geoffroyi), white-faced capuchin (Cebus capucinus), brown-throated three-toed sloths (Bradypus variegatus), silky anteaters (Cyclopes didactylus) and nine-banded armadillos (Dasypus novemcintus). Also in this ecoregions are carnivores such as ocelot (Leopardus pardalis), central american otter (Lutra annectens), jaguar (Panthera onca), northern racooon (Procyoon lotor) and crab-eating racoon (P. cancrivorus). Reptiles include the basilisk lizard (Basiliscus basiliscus), caiman (Caiman crocodilus), green turtle (Chelonia mydas), leatherback turtle (Dermochelys coriacea) and green iguana (Iguana Iguana). The beaches along the coast within this ecoregion near Tortuguero are some of the most important for nesting green turtles. Several species of frogs (Dendrobatidae) and salamanders that are also endemic.
The ecoregion is of great importance as a stopover for migratory birds and is a breeding area for a number of fish that are important to the subsistence economy of the ecoregion. Birds that visit mangroves during migration include spotted sandpiper (Actitis macularia), red-lored Amazon (Amazona autumnalis), snowy cotinga (Carpodectes nitidus), Wilson’s plover (Charadrius wilsonia), green kingfisher (Chloroceryle americana), lesser nighthawk (Chordeiles acutipennis), common nighthawk (Chordeiles minor), keel-billed motmot (Electron carintum) and osprey (Pandion haliaetus) just to name a few.
There also appears to be an increased incidence of tropical storms and hurricanes. According to data for the Corn Islands which are just outside the boundaries of this ecoregion, suggest that tropical storms occur on an average of once a year and that hurricanes are expected once every fifty years. However, in 1996, three tropical storms and one hurricane occurred, and three hurricanes have struck the Corn Islands in the past 8 years (Ryan et al. 1998). Although it is not possible to unequivocably link these particular extreme events with climate change, an increase in their frequency is consistent with the predicted effects of climate change, in that they have a tendency to occur in warmer waters (Kjerfve and Macintosh 1997).
The protected areas in this region, include the Indio Maíz biological reserve in Nicaragua and the Tortuguero National Park and the Humedal Caribe Noreste in Costa Rica, are part of a network of Caribbean sites linked by a Meso-American Biological Corridor intended to insure continuity of biogeographical links between north and south America. The Humedal Caribe Noreste is also considered a wetland of international importance under the RAMSAR convention.
Types and Severity of Threats
Deforestation in the upper watershed has resulted in drainage and sedimentation problems. Also associated with these problems are the acceptable management practices used on banana plantations. The redirection of surface water flow as a result of dam construction is changing the mangrove habitat by either adding or removing the natural amount of freshwater inflow to the ecoregion. A list of other threats includes land use changes as a result of unplanned settlements, illegal hunting, development of an international port, plans for another canal between the Caribbean Sea and the Pacific Ocean, gold mining on the Nicaraguan side of the border, sewage contamination from towns, runoff of agricultural chemicals, and erosion. For lack of a unified management plan, these threats appear to vary depending on the side of the border and are more acute in Costa Rica (Frazier 1999; OAS USDE doc).
Justification of Ecoregion Delineation
Classification and linework for all mangrove ecoregions in Latin America and the Caribbean follow the results of a mangrove ecoregion workshop (1994) and subsequent report (Olson et al. 1996).
Kjerfve, B., and D.J. Macintosh. 1997. The impact of climatic change on mangrove ecosystems. B. Kjerfve, L.D. Lacerda, and E.H.S. Diop E.H.S., editors. Mangrove ecosystem studies in Latin America and Africa. UNESCO, Paris France.
Ecoregional Workshop: A Conservation Assessment of Mangrove Ecoregions of Latin America and the Caribbean. 1994. Washington D.C., World Wildlife Fund.
Olson, David M., Eric Dinerstein, Gilberto Cintrón and Pia Iolster. 1996. A Conservation Assessment of Latin America and the Caribbean: Report from WWF's Conservation Assessment of Mangrove Ecorsystems of Latin America and the Caribbean Workshop. WWF, Washington D.C.
Roth, L.C. 1997. Implications of periodic hurricane disturbance for the sustainable management of caribbean mangroves. B. Kjerfve, L.D. Lacerda, and E.H.S. Diop, editors. Mangrove ecosystem studies in Latin America and Africa. UNESCO, Paris France.
Ryan, J.D., L.J. Miller, Y. Zapata, O. Downs, and R. Chan. 1998. Great Corn Island, Nicaragua. B.Kjerfve, editor, Caribbean coral reef, seagrass and mangrove sites. UNESCO, Paris France.
Tomlinson, P.B. 1994. The Botany of Mangroves. Cambridge University Press. Pages 166-168.
Prepared by: Sylvia Tognetti and Christine Burdette
Reviewed by: In process