Species Details

Details of Oriental Mangrove will be displayed below

Oriental Mangrove   

Common Name: Large Leafed Orange Mangrove
Scientific Name: Bruguiera gymnorhiza
Local Name: Boda Vaki, Bodu Kandoo
Dhivehi Name: ބޮޑަވަކި، ބޮޑު ކަނޑޫ
Plantae  (Kingdom)
Tracheophyta  (Plylum)
Magnoliopsida  (Class)
Malpighiales  (Order)
Rhizophoraceae  (Family)
Bruguiera   (Genus)

Oriental Mangrove's description

A small to moderately sized, evergreen tree that is capable of growing to 35 m tall but most of the trees found in the Maldives are 6 to 10 m in height. It is a single-stemmed tree with short buttresses and characteristic knee-shaped above-ground breathing roots. Bark is pale grey or brown, thick, hard and rough. Leaves are simple, opposite in arrangement, leathery, dark green in colour, 8 to 22 cm long and 5 to 8 cm wide with 2 to 5 cm long leaf stalk. Flowers are single and axillary in position. Calyx is reddish to scarlet in colour with ten to 14 pointed lobes, which are smooth or with grooves above lobe junctures. Petals are orange-brown in matured flowers, bilobed and each lobe has three to four long bristles. Viviparous propagules are cigar shaped, 15 to 25 cm in length, 1.5 to 2 cm in diameter, stocky with blunt narrowed apex. Propagules detach with calyx, buoyant and dispersed by currents.

Occurrence in Maldives:  It is found growing as a dominant or co-dominant species in many of the mangrove ecosystem of the Maldives. This species often occurs with the Tall-stilted Mangrove (Rhizophora apiculata, Thakafathi) in areas that receive some freshwater. In the Maldives it is found in Hoededhoo (Gaaf Dhaal), Filladhoo (Haa Alif), Gan (Laamu), Huraa (Kaafu).

Oriental Mangrove's facts

The name gymnorhiza comes from two Greek words "gymno" naked and "rhiza" root, naked root which refers to the exposed knee roots of Bruguiera gymnorhiza emerging from the ground.

 

The main difference from other Bruguiera species is that Bruguiera gymnorhiza has the largest leaves, flowers, propagules and lenticels of all Bruguiera species.

 

The name Large-Leafed Orange Mangrove comes from the orange flowers and the large leaves that can reach up to 25cm in length.

 

Bruguiera gymnorhiza was described for the first time in 1798 by avigny ex Lam. & Poiret.

Oriental Mangrove's Behavior & Ecology

It is capable of growing well in somewhat dry and well-aerated soil in the mid- and high- tidal areas of the intertidal zone. It tolerates up to 50 ppt of soil salinity but optimal salinity range is reported to be between 8 and 26 ppt. It is one of the most shade tolerant mangrove species and seedlings may grow under a full forest canopy. It is propagated by propagules. Matured propagules are reddish-brown or greenish-red in colour. Fresh and healthy propagules can be collected from the mother trees or freshly fallen propagules without any damage can be used for planting. Propagules can be stored for about a week by keeping the lower portion in brackish water or by wrapping them with wet jute bags. Propagules can be directly planted in selected fields by inserting them up to one–third of their length. Nursery-raised seedlings about 35 cm in height can be used for outplanting. Direct planting is most successful and economical.

Oriental Mangrove's Conservation

Mangroves in general are under threat from coastal development, and this species, which grows on the landward edge of the mangrove area, may be more threatened by rising sea levels than are other species because it may be unable to move further inland. There may be a decline in populations of this species due to habitat loss or harvesting, but it is a common species of mangrove with a very wide range, and is not declining at a sufficient rate to be included in any threatened category, so it is listed by the International Union for Conservation of Nature as being of "least concern".

Oriental Mangrove's Relationship with Humans

The wood of Bruguiera gymnorhiza has very high density and therefore very heavy wood which made it very attractive as timber for the use of saltwater and foundation pilings, house posts, flooring, cabinetwork and furniture.

Bruguiera gymnorhiza was also used as source of dyes for fishnets, ropes, sails and clothing.

Powdered bark was used for the preparation of tuba, a very popular, alcoholic drink in the Philippines made from coconut sap.

Nowadays charcoal and firewood is made of Bruguiera gymnorhiza in the Philippines while the knee roots are utilized in planting rituals so cultivated tubers will grow big.

Tiwi people use the timber of Bruguiera gymnorhiza to make throwing sticks for hunting magpie gees.

Macassar, the biggest port in the south of Indonesia was the main trade center for sea cucumbers in the 18th century. The sea cucumbers have been catched on surrounding small islands and been shipped to China, in that time the most important export product of Macassar to China. People produced a red dye of Bruguiera gymnorhiza which was used to treat trepang.

In the Maldives, propagules are consumed regularly during the fruiting season. They are peeled, soaked and boiled three or four times in water and eaten. Sometimes they are cooked with salt, dried and then consumed. Though the timber is hard and tough it is not widely used because it easily decays. Bark is used for tanning fishing nets.

Oriental Mangrove habitat

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).

Oriental Mangrove threats

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.

Oriental Mangrove's status