Rio Piranhas mangroves
West Indian manatee (Source: Ramos Keith, U.S. Fish and Wildlife Service Domain, via Wikimedia Commons)
Introduction These mangroves are found in the semi-arid northeastern region of Brazil (Rio Piranhas mangroves) where they are confined to estuaries and river mouths, interspersed with large sand dunes. Their concentration of nutrients supports a great diversity of species associated also with adjacent sea grasses and coral reefs. This mangrove ecoregion extends discontinuously, along a long line of the Atlantic Ocean coast, as vegetation patches. These mangrove patches are all composed of the same genera; Avicennia, Lagunculasis, and Rhizophora only in different combinations or even occurring as the only dominant species, depending on the patch location. Much of the ecoregion is protected but for areas that are not, urban expansion poses a great threat.
Location and General Description
This ecoregion encompasses a long yet discontinuous patch of mangroves that extends from around the Rio Tinto (Paraíba) southward to around Maceió (Alagoas), just south of Rio Largo. There is a patch around the estuary of the River Mamanguape; one around João Pessoa; one large patch occupying the entire coast of Pernambuco, from the River Goiana to Rio Formoso; and one around Maceió. Small patches of mangroves are found, of course, among these main patches. Because of the ocean's high energy along this coast, in some areas mangroves are restricted to estuaries and coastal lagoons. The climate is tropical humid with 1 to 2 dry months. Annual rainfall] ranges from 1,800 to 2,100 millimeters (mm).
The vegetation is 9 to 20 meters (m) tall and basically composed of three species: red mangrove (Rhizophora mangle), black mangrove (Avicennia shaueriana), and white mangrove (Laguncularia racemosa). Other species that were recorded in the mangroves are Conocarpus erectus, Dalbergia ecastophyllum, and Psittacanthus dichrous. Associated with mangroves are large areas of seagrasses that are critical to the maintenance of biological flows in the mangrove ecosystems. These seagrasses are found on calm waters, in a intermediary position between the sea and estuaries. Along the Rio Piranhas mangroves, four plant species are found on these seagrasses (Holodule wrightii, Halophila baillonii, Halophila decipiens, and Ruppia maritima), but Holodule wrightii is by far the dominant species along the Pernambuco Coast.
Biodiversity Features
The most outstanding feature of the biodiversity of the Rio Piranhas is the presence of the only known population of the highly threatened West Indian manatee (Trichechus manatus) along the eastern Brazilian Coast. Mangroves of this ecoregion are also very important for several migrant birds including ruddy turnstone (Arenaria interpres), spotted sandpiper (Actitis macularia), green-backed heron (Butorides striatus), and bi-colored conebill (Conirostrum bicolor) and whimbrel (Numenius phaeopus) that use them as feeding and resting places from August through April during their extraordinary intercontinental journey. According to Stattersfield et al. and Birdlife International, an Endemic Bird Area falls in the northern most mangrove areas of this ecoregion. Although no species are listed as mangrove habitat restricted many utilize the surrounding tropical evergreen forests or are listed as specific to flat lowland forest. The Mitu mitu is one of these species but it is considered extinct in the wild due to habitat conversion.
A number of snail species (Anomalocardia brasiliana, Mytella falcata, and Crassostrea rhyzophorae) found in this ecoregion have a high socio-economic importance, as they are pivotal resources for a large human population that lives near mangroves.
Current Status
There is a wide variation in status and threats regarding Rio Piranhas mangroves. At one extreme are the mangroves of the River Mamanguape and around Ilha de Itamaracá (Pernambuco) which are within protected areas and therefore harbor most of their original biodiversity. At another extreme are those mangroves located near the major cities as Recife, João Pessoa, and Maceió which are under high risk caused by urban expansion, wood extraction, and pollution caused by agriculture and industries.
Types and Severity of Threats
Although most of the mangroves of these [[ecoregion]s] have previously been disturbed, and are currently threatened by urban expansion there are still opportunities to build a efficient conservation system to protect them. Other threats come from oil exploration and cutting of mangrove habitat. Good conservation planning associated with sustainable use of the mangroves' biodiversity makes up the main strategy for ensuring the maintenance of the unique biodiversity of the River Piranhas mangroves.
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 and subsequent report.
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
- Azevedo Júnior, S. M., and M. E. Larrazabal. 2000. Aves: Biologia, Ecologia e Movimentação. Pages 155-162 in H. M. Barros, E. Eskinazi-Leça, S. J. Macedo and T . Lima, editors, Gerenciamento participativo de estuários e manguezais. Recife: Editora Universitária da UFPE.
- Ecoregional Workshop: A Conservation Assessment of Mangrove Ecoregions of Latin America and the Caribbean. 1994. Washington D.C., World Wildlife Fund.
- Magalhães, K. M., and E. Eskinazi-Leça. 2000. Os prados de fanérogamas marinhas. Pages 39-47 in H. M. Barros, E. Eskinazi-Leça, S. J. Macedo and T . Lima, editors, Gerenciamento participativo de estuários e manguezais. Recife: Editora Universitária da UFPE.
- Mello, R. L. S., and D. O. Tenório. 2000. A Malacofauna. Pages 103-118 in H. M. Barros, E. Eskinazi-Leça, S. J. Macedo and T . Lima, editors, Gerenciamento participativo de estuários e manguezais. Recife: Editora Universitária da UFPE.
- 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.
- Schuler, C. A. B., V. C. Andrade, and D. S. Santos. 2000. O Manguezal: composição e estrutura. Pages 27-38 in H. M. Barros, E. Eskinazi-Leça, S. J. Macedo and T . Lima (editors), Gerenciamento participativo de estuários e manguezais. Recife: Editora Universitária da UFPE.
- Spalding, Mark, Francois Nlasco and Colin Field.1997. World Mangrove Atlas. Smith Settle, Otley, West Yrokshire, UK.
- Stattersfield, Alison J., Michael J. Crosby, Adrian J. Long, and David C. Wege. 1998. Endemic Bird Areas of the World: Priorities for Biodiversity Conservation. BirdLife International. The Burlington Press, Cambridge, UK. ISBN: 1560985747
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