|Scientific Name:||Laguncularia racemosa|
|Species Authority:||(L.) C.F.Gaertn|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Ellison, A., Farnsworth, E. & Moore, G.|
|Reviewer/s:||Polidoro, B.A., Livingstone, S.R. & Carpenter, K.E. (Global Marine Species Assessment Coordinating Team)|
This species is widespread and tolerant of a variety of habitats. Relative to the other mangrove species within the wider Caribbean, the conservation status of this species appears to be more stable. However, this species is threatened by the loss of mangrove habitat throughout its range, primarily due to extraction and coastal development. There has been an estimated 17% decline in mangrove area within this species range since 1980. Mangrove species are more at risk from coastal development and extraction at the extremes of their distribution, and are likely to be contracting in these areas more than in other areas. It is also likely that changes in climate due to global warming will further affect these parts of the range. Therefore there are overall range declines in many areas, but not enough to reach any of the threatened category thresholds. This species is listed as Least Concern.
|Range Description:||The distribution of this species is restricted to the neotropics and West Africa (Tomlinson, 1986). It has been reported from the eastern tropical coasts of North and South America (ranging from Florida, U.S., 28°50', to Laguna, Brazil, 28°30') and all Caribbean Islands except Bermuda, Dominca and Netherlands Antilles; status on Anguilla is unknown (Wilkie and Fortuna 2003). It has been noted on the Pacific coast of South America from Estera Sargento, Mexico (29°17') south to Piura River, Peru (5°32') (de Lacerda, 2002). It is also noted from West Africa (Angola, Benin and Togo, Cameroon, Côte d'Ivoire, Democratic Republic of the Congo, Gabon, Gambia, Ghana, Guniea, Guinea-Bisau, Nigeria, Senegal, and Sierra Leone (Spalding et al. 1997). It is absent in the Galapagos Islands, Cocos, and Malpelo, and Canary Islands.
The south mid-Atlantic Island distributions should be confirmed.
Native:Angola (Angola); Anguilla; Antigua and Barbuda; Bahamas; Barbados; Belize; Benin; Brazil; Cameroon; Cayman Islands; Colombia; Congo; Congo, The Democratic Republic of the; Costa Rica; Côte d'Ivoire; Cuba; Dominica; Dominican Republic; Ecuador; El Salvador; Equatorial Guinea; France; French Guiana; Gabon; Gambia; Ghana; Grenada; Guadeloupe; Guinea; Guinea-Bissau; Guyana; Haiti; Honduras; Jamaica; Liberia; Mexico; Montserrat; Netherlands Antilles; Nicaragua; Nigeria; Panama; Peru; Saint Kitts and Nevis; Saint Lucia; Saint Vincent and the Grenadines; Senegal; Sierra Leone; Suriname; Togo; Trinidad and Tobago; Turks and Caicos Islands; United States; United States Minor Outlying Islands; Venezuela; Virgin Islands, British
|FAO Marine Fishing Areas:||
Atlantic – eastern central; Atlantic – southeast; Atlantic – southwest; Atlantic – western central; Pacific – eastern central; Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
Although there is no species specific population information, it can be assumed that there are areas of population decline throughout its range due to coastal development.
Individual population sizes are highly variable through time, as mortality of seedlings can be quite high due to competition with other mangroves (Sherman et al. 2001, Ross et al. 2006). Seedlings recruit in thousands following a disturbance (Sherman et al. 2001). Saplings and trees can number in thousands in a few areas, but Laguncularia tends to be less populous in a given mangal than the other Afrotropical species, with low importance values and basal area (Murray et al. 2003).
Eastern and western Atlantic provenances of Laguncularia show significant genetic differentiation, as indicated by leaf chemistry (Dodd et al. 1998). There have been no other genetic studies to date.
|Habitat and Ecology:||
This species tends to be found at the upper margins of the mangrove-upland interface, or high intertidal region, and not at the seaward margin (Tomlinson 1994, Sherman et al. 2001). Seedlings are less tolerant of salinity and changing hydroperiod than R. mangle (Cardona-Alarte et al. 2006). Although it is a pioneer and can establish in relatively open sites with low salinity and abundant nutrients, mortality of seedlings is nearly 100% (Tomlinson 1995).
However, more important is the role of mangroves as nurseries for juvenile phases of economically-important fish and crustaceans. Laguncularia, being a landward mangrove, contributes to this indirectly by buffering upland pollutants.
Laguncularia is likely to be susceptible to increasing tidal height or salt intrusion, especially under conditions of sea-level rise (Ross et al. 2000). The invasive alien species, Schinus terebrinthifolius, is directly impacting populations in Florida (Schmalzer 1995, Herwitz et al. 1996, Gordon 1998, Ewe and Sternberg 2005). The species tends to be outcompeted by Rhizophora mangle; the native fern, Acrostichum aureum, may also affect seedling establishment. In addition, altough marine aquaculture is not documented specifically from the Caribbean, on the Pacific coast it is negatively impacting Laguncularia (Kovacs 1999). Although local estimates are uncertain due to differing legislative definitions of what is a 'mangrove' and to the imprecision in determining mangrove area, current consensus estimates of mangrove loss in the last quarter-century report an approximately 17% decline in mangrove areas in countries within this species range since 1980 (FAO 2007).
Laguncularia has a higher requirement for freshwater inputs than other mangrove species, so may be vulnerable to drought. Storms/floods/hurricanes have extensively damaged Laguncularia stands (Roth 1992, McCoy et al. 1996, Sherman et al. 2001, Piou et al. 2006, Ross et al. 2006). Laguncularia experiences high mortality and leaf loss during freeze events at the northern edge of its range in Florida (Ellis et al. 2006).
Selective logging is also a possible threat as this species is regarded as suitable for polewood construction on Pacific coast of Mexico (Kovacs 1999). Clear-cutting is occurring in certain areas (Suman 1994); loss rates are estimated at 1.4%/year for Laguncularia/Avicennia-dominated mangal in western Mexico (Ramirez-Garcia et al. 1998). Clearing of mangal for settlement and agriculture cited as major cause of decline in Latin America (Lacerda 1993) without a compensating economic return from agriculture or fast mangrove recovery (Tovilla-Hernandez et al. 2001). Subsistence use of Laguncularia for fuelwood occurs (Kovacs 1999).
All mangrove ecosystems occur within mean sea level and high tidal elevations, and have distinct species zonations that are controlled by the elevation of the substrate relative to mean sea level. This is because of associated variation in frequency of elevation, salinity and wave action (Duke et al. 1998). With rise in sea-level, the habitat requirements of each species will be disrupted, and species zones will suffer mortality at their present locations and re-establish at higher elevations in areas that were previously landward zones (Ellison 2005). If sea-level rise is a continued trend over this century, then there will be continued mortality and re-establishment of species zones. However, species that are easily dispersed and fast growing/fast producing will cope better than those which are slower growing and slower to reproduce.
In addition, mangrove area is declining globally due to a number of localized threats. The main threat is habitat destruction and removal of mangrove areas. Reasons for removal include cleared for shrimp farms, agriculture, fish ponds, rice production and salt pans, and for the development of urban and industrial areas, road construction, coconut plantations, ports, airports, and tourist resorts. Other threats include pollution from sewage effluents, solid wastes, siltation, oil, and agricultural and urban runoff. Climate change is also thought to be a threat, particularly at the edges of a species range. Natural threats include cyclones, hurricane and tsunamis.
There are no conservation measures specific to this species, but its range may include some marine and coastal protected areas. More research is needed on the effects of ongoing sea level rise on Laguncularia, given its low salinity tolerance. Likewise, the impacts of invasive species (and consequences of their removal) on Laguncularia need to be quantified.
The effectiveness of habitat restoration and success of replantings with Laguncularia needs to be assessed. New Landsat and IKONOS technology should be used to do species-based, landscape-level monitoring of deforestation (Kovacs et al. 2005). More research needed is on Laguncularia influences on water quality, erosion control, and pollution buffering.
Restoration of Laguncularia is being pursued in Florida (Milano 1999, McKee and Faulkner 2000), Costa Rica (Lewis and Marshall 1998) and Colombia (Elster and Perdomo 1999, Elster 2000). See valuable general review by Lewis (2005). More information and forestry trials are needed to optimize silvicultural techniques and management.
|Citation:||Ellison, A., Farnsworth, E. & Moore, G. 2010. Laguncularia racemosa. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 25 May 2013.|
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