|Scientific Name:||Bruguiera gymnorhiza|
|Species Authority:||(L.) Lam.|
|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 and very common within its range. 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 20% 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:||In South Asia, this species is found in Brunei Darussalam, Cambodia, China, Hong Kong, India, Indonesia, Japan, Malaysia, Myanmar, Philippines, Singapore, Sri Lanka, Thailand, Viet Nam, and Bangladesh. In Australasia it is found in American Samoa, Northwest Australia, Northeast Australia, Southeast Australia, Federated States of Micronesia, Fiji, Guam, New Caledonia, Palau, Papua New Guinea, Solomon Islands, Tonga, Vanuatu, and Western Samoa. In East Africa and the Middle East, it is found in Kenya, Madagascar, Maldives, Mauritius, Mozambique, Seychelles, Reunion, Somalia, South Africa, Tanzania. This species is extinct in Yemen.|
Native:American Samoa (American Samoa); Australia; Bangladesh; Brunei Darussalam; Cambodia; China; Christmas Island; Comoros; Fiji; Guam; India; Indonesia; Japan; Kenya; Kiribati; Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius; Mayotte; Micronesia, Federated States of; Mozambique; Myanmar; Nauru; New Caledonia; Northern Mariana Islands; Pakistan; Palau; Papua New Guinea; Philippines; Réunion; Samoa; Seychelles; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Tonga; Vanuatu; Viet Nam; Wallis and Futuna
|FAO Marine Fishing Areas:||
Atlantic – southeast; Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species is the one of the most widely distributed mangrove species, and is considered common throughout its range. For example, in India, this species was found in 50% of 100 sampling sites (Kathiresan 2008). Its numbers are increasing in Japan where it competes with R. stylosa. However, this species has been considered locally extinct in Taiwan for at least the past 10 years.There are two color forms: red calyces (which is the predominant form), and white and green calyces.|
|Habitat and Ecology:||
This species is found in downstream to intermediate estuarine zones in the mid to high intertidal region. It is shade tolerant with a maximum porewater salinity of 50 ppt and a salinity of optimal growth of 8-34ppt (Robertson and Alongi 1992). This species has minor coppicing, and is relatively slow-growing with low regeneration rates. It cannot tolerate high salinity, and requires the shade and protection of surrounding trees to survive.
It is a small to large buttressed tree that can grow to 25 m but more commonly is found up to 10 m. The trunk is characterised by lenticels. It is found on deep muddy shore, in association wth Kandelia candel in a the parts of its range where K. candel is found. It is often scattered along the shore inland of the river mouth (Peng and Xin-men 1983).
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 20% decline in mangrove areas in countries within this species range since 1980 (FAO 2007).
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. Continued monitoring and research is recommended, as well as the inclusion of mangrove areas in marine and coastal protected areas. This species is grown in plantations in India, and perhaps in other parts of its range.|
|Citation:||Duke, N., Kathiresan, K., Salmo III, S.G., Fernando, E.S., Peras, J.R., Sukardjo, S. & Miyagi, T. 2010. Bruguiera gymnorhiza. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 23 May 2013.|
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