Amapa mangroves
Introduction
The mangroves of the Amapa ecoregion (Amapa mangroves) are found in an ecotone or zone of transition between several different ecosystems that include flooded forests and grasslands, savannas and tropical rainforest. Like other mangrove ecoregions on the north coast of Brazil, they are exceptionally well developed because of high inputs of freshwater from rainfall and from the most extensive river system in the world,focused around the Amazon Basin. They can also be found far inland because of flat topography and a high tidal range.
Location and General Description
The coast of Amapa ecoregion is north of the Mouths of the Amazon River area. This ecoregion is fragmented by natural processes including patches of mangrove growth that occurs where conditions are favorable. The Canal de Norte flows into the Atlantic Ocean just south of the southern most mangrove block within this ecoregion. The ocean currents in this part of South America flow north, up the coast carrying the sediments and fresh water, released by the Amazon River and its tributaries, along with them to deposit large quantities of fine grained clay and sediment. These form hundreds of islands and mudflats that are continuously colonized by mangroves, and an intricate network of canals.
The northern most patch of mangrove habitat that is part of this ecoregion occurs where the Cassipore River flows into the Atlantic Ocean creating a small bay like area. High tidal ranges of over 5 meters (m), combined with flat topography, allow the mangroves to cover extensive inland areas; up to 40 km from the coast. The climate is humid tropical with a mean temperature between 25 and 26 °C, high rainfall of up to 4,000 millimeters (mm) a year, and a very short dry season of two months. The combination of high rainfall with high freshwater input from an extensive river system results in mangrove vegetation is found in association with palms and freshwater macrophytes.
Biodiversity Features
Rhizopora mangle is the most conspicuous mangrove species as it is found closest to the coast and in estuarine areas where there is direct marine influence while attaining heights of up to 25 meters. Also particularly well developed along the north coast of Brazil is Avicennia germinans and A. schaueriana, which may be over 1 meter in diameter and reach heights of up to 45 meters. Other true mangrove species found in this ecoregion are Rhizopora racemosa, R. harrisonii, Laguncularia racemosa and Conocarpus erectus, which are found landward of R. mangle. Non-tree species associated with these mangroves are Spartina alterniflora that grows on the seaward fringe, and Hibiscus tiliaceus and the fern Acrostichum aureum, that are both found in the landward margins and dry saline areas within mangroves. Species found associated with these mangroves because of their location adjacent to tropical forests and because of high freshwater input include the tropical forest species, leguminosae vine (Dalbergia brownei), and Apocynaceae liana (Rhabdadenia biflora) as well as freshwater macrophytes, Araceae Montrichardia arborescens, and Leguminosae Mora oleifera; and palm species, Euterpe oleracea and Orbygnia martiana. Although little information is available, because of the location of the Amapa mangroves adjacent to flooded forests, savanna and tropical rain forest ecosystems, it is likely that plant species associated with them may also be found, and that many animal species from these ecosystems may be found as visitors.
Many species with a more generalized distribution can also be found in mangroves, particularly in the mangrove ecoregions on the north coast of Brazil, where the mangrove vegetation is mixed with that associated with freshwater. The following species are among those more specialized in the use of mangrove habitats or more likely to be found there. Birds include species such as orange winged parrot (Amazona amazonica), white-necked heron (Ardea cocoi), rufous crab-hawk (Buteogallus aequinoctialis), striated heron (Butorides striatus), semi-palmated sandpiper (Calidris pusilla), great egret (Casmerodius albus), green kingfisher (Chloroceryle americana), bicolored conebill (Conirostrum bicolor), greater ani (Crotophaga major), little blue heron (Egretta caerulea) and many others. Rare and endangered species found in this region include the birds scarlet ibis (Eudocimus ruber), and wattled jacana (Jacana jacana), the mammals, manatee (Trichechus manatus), and two marine turtles, the green turtle (Chelonia mydas) and the leatherback (Dermochelys coriacea).
Mammals including agouti (Agouti paca), bearded saki monkey (Chiropotes satanas), brown capuchin monkey (Cebus apella), crab-eating fox (Cerdocyon thous), tayra (Eira barbara), jaguarundi (Herpailurus yaguarondi), capybara (Hydrochaeris hydrochaeris), ocelot (Leopardus pardalis), little spotted cat (Leopardus wiedii), otter (Lontra longicaudis), coati (Nasua nasua), jaguar (Panthera onca), crab-eating raccoon (Procyon cancrivorous), giant river otter (Pteronura brasiliensis), puma (Puma concolor), tucuxi (Sotalia fluviatilis), tapir (Tapirus terrestris), and howler monkey (Alouatta sp.) as well as others enter the mangrove habitat to find resource such as food, refuge and water.
Current Status
This ecoregion contains approximately 13% of the total Brazilian mangrove vegetation type area, which is largely intact because of low population density and relative inaccessibility. Protected areas in the coastal zone include the Cabo Orange National Park as well as other kinds of protected areas that include an environmental protection area, two biological reserves, an extractive reserve, an ecological station, and a national forest. It is not clear what percentage of these consist of mangroves.
Types and Severity of Threats
The greatest threat to this ecoregion is the over exploitation of its resources leaving it in a nonrenewable state. These mangroves are important to the subsistence economy of numerous artisanal fishermen, particularly for their abundance of crabs. In addition to fishing, mangroves are used as a timber resource for construction of boats and houses, and their barks as a source of tannin used to dye ship sails. They are also used for firewood and charcoal. The main commercial economic activities of the ecoregion that raise environmental concerns are extraction and export of timber, minerals, fish, crabs and shrimp, products made from palm trees, chestnuts, rubber and oil, as well as grazing of livestock. The most direct impact on mangroves is the harvesting of crabs, which is a keystone species in mangrove ecosystems.
Justification of Ecoregion Delineation
Classification and linework for all mangrove [[ecoregion]s] in Latin America and the Caribbean follow the results of a mangrove ecoregion workshop (1994) and subsequent report of Olson et al.
Additional information on this ecoregion
- For a shorter summary of this entry, see the WWF WildWorld profile of this ecoregion.
- To see the species that live in this ecoregion, including images and threat levels, see the WWF Wildfinder description of this ecoregion.
- World Wildlife Fund Homepage
Further Reading
- BDT, Baso de Dados Tropical, 2001. Prioridades de conservação para a avifauna da Amazônia: Aves do Amapá.
- Dunning, J.S. 1987. South American birds: a photographic aid to identification. Harrowood Books, Newton Square PA.
- Ecoregional Workshop: A Conservation Assessment of Mangrove Ecoregions of Latin America and the Caribbean. 1994. World Wildlife Fund, Washington D.C.
- Eisenberg, J.F. and K.H. Redford. 1999. Mammals of the neotropics: the central neotropics. Volume 3: Ecuador, Peru, Bolivia, Brazil. The University of Chicago Press, Chicago and London.
- Kjerfve, B. and L.D. Lacerda. 1993. Mangroves of Brazil. In: Lacerda L.D. ed. Conservation and sustainable utilization of mangrove forests in Latin America and Africa Regions. Part I: Latin America. International Society for Mangrove Ecosystems and the International Tropical Timber Organization.
- Olson, D.M., E. Dinerstein, G. Cintrón, and P. Iolster. 1996. A conservation assessment of mangrove ecosystems of Latin America and the Caribbean. Final report for The Ford
- Foundation. World Wildlife Fund, Washington, D.C.
- Schaeffer-Novelli, Y. 1999. (Consultora). Evaluation and priority actions for the conservation of the biodiversity of the marine and coastal zone. PRONABIO Projeto de conservação e utilização sustentável da diversidade biológica Brasileira - PROBIO. São Paulo, Brasil.
- Sick, H. 1993. Birds in Brazil: a natural history. Princeton University Press, Princeton NJ.
- Ubiratan Moreira dos Santos, J., I. de Sousa Gorayeb, M. de Nazaré do Carmo Bastos 1999. Avaliação e ações prioritarias para a conservação da biodiversidade da zona costeira e marinha. Diagnóstico da situação para a conservação da biodiversidade da zona costeira e marinha amazônica. Ministerio do Meio Ambiente and Projecto de Conservação e Utilização Sustantável da Diversidadie Biológica Brasiliera. Belém, Pará, Brasil.
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