|Scientific Name:||Avicennia alba|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Duke, N., Kathiresan, K., Salmo III, S.G., Fernando, E.S., Peras, J.R., Sukardjo, S. & Miyagi, T.|
|Reviewer/s:||Polidoro, B.A., Livingstone, S.R. & Carpenter, K.E. (Global Marine Species Assessment Coordinating Team)|
This species is widespread, is fast-growing and can be locally common. It is threatened by the loss of mangrove habitat throughout its range, primarily due to extraction and coastal development, and there has been an estimated 24% 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. Although there are overall range declines in many areas, they are not enough to reach any of the threatened category thresholds. This species is listed as Least Concern.
|Range Description:||This species occurs in South Asia, including Darussalam, India, Bangladesh, Indonesia, Malaysia, Brunei, Myanmar, Philippines, Singapore, Thailand, and the southcentral coast of Viet Nam. In Australasia, it is found in the Yap Islands (Federated States of Micronesia), Palau, northern Papua New Guinea, and the Solomon Islands.|
Native:Bangladesh; Cambodia; India; Indonesia; Malaysia; Micronesia, Federated States of; Myanmar; Palau; Papua New Guinea; Philippines; Singapore; Solomon Islands; Thailand; Viet Nam
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Indian Ocean – western; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
This species can be locally common throughout its range. In India, this species was present in 65 of 100 sampling sites (Kathiresan 2008).
There are several varieties of this species that may be reflected in leaf morphology and is reflected in preliminary genetic studies (Duke et al. 1998). It is known that leaf morphlogy is influenced by environmental factors, including salinity, insect damage (Kathiresan 2008), nutrients, and sun exposure. Avicennia is a pantropical genus of about 8 species occupying diverse mangrove habitats. They can occur within the normal tide range or in back mangrove areas. They have a high tolerance to hypersaline conditions (Tomlinson 1986).
|Habitat and Ecology:||This species is found along tidal riverbanks in the downstream estuarine zone, and in the lower and middle intertidal region (Robertson and Alongi 1992). It occurs as a tree or shrub that grows to 25 m, often around 10 m. It is fast-growing and sprouts easily from coppicing. Both Avicennia and Sonneratia species are the colonizing species on newly formed mudflats in SE Asia (Terrados et al. 1997).|
|Systems:||Terrestrial; Freshwater; Marine|
The major threat to this species is conversion of tidal wetlands to fish ponds and other land uses within its range.This species is locally threatened due to destruction of mangrove habitat within its range, particularly at the extremities of its range. Mangrove habitat within this species range has declined at least 24% (FAO 2007) over a twenty-five year period (1980-2005).
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.
|Conservation Actions:||There are no conservation measures specific to this species, but its range may include some marine and coastal protected areas. This species may be planted in some areas within its range. Continued monitoring and research is recommended, as well as the inclusion of mangrove areas in marine and coastal protected areas.|
|Citation:||Duke, N., Kathiresan, K., Salmo III, S.G., Fernando, E.S., Peras, J.R., Sukardjo, S. & Miyagi, T. 2010. Avicennia alba. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 25 May 2013.|
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