Species Details

Details of Red Mangrove will be displayed below

Red Mangrove   

Common Name: Asiatic Mangrove, Loop-root Mangrove
Scientific Name: Rhizophora mucronata
Local Name: Randoo
Dhivehi Name: ރަނޑޫ
Plantae  (Kingdom)
Tracheophyta  (Plylum)
Magnoliopsida  (Class)
Malpighiales  (Order)
Rhizophoraceae  (Family)
Rhizophora   (Genus)

Red Mangrove's description

A small, erect, evergreen tree 6 to 10 m tall with knee-like above-ground breathing roots. These knee roots comprise a sponge like system of air chambers, which act as an air reservoir when the roots are submerged. These roots are also covered with numerous pores, which allow air but not water to enter the root. Bark is light to dark grey or pale pink in colour and scaly at the bottom. Leaves are simple, opposite in arrangement, lanceolate in shape, about 7 to 12 cm long, shiny, dark green in colour with pointed apex. Inflorescence is a three-flowered cyme with about 1 cm long peduncle and axillary in position. Flowers are small, white in colour with 8-lobed greenish-yellow calyx, which is persistent, forming a cap-like structure above the propagules. Propagules are spindle shaped, 10 to 15 cm long, 0.5 to 1 cm in diameter, smooth, slightly curved, cylindrical and green to purplish-green in colour, which are buoyant and dispersed by currents.

 

Distribution: Red Mangrove is a species of mangrove found on coasts and riverbanks in East Africa and the Indo-Pacific region.

Red mangrove is found either as a dominant or co-dominant species in many of the mangrove ecosystem of the Maldives. It also found in the form of pure stands. A large number of young seedlings are found growing in the areas wherever this species is dominant.

Red Mangrove's Behavior & Ecology

It grows on light, medium and heavy soil but prefers silty clay soil and high- and mid- tidal zone for better performance. Its optimum soil salinity ranges from 8 to 34 ppt. It is propagated by propagules. Unlike in Avicennia spp., propagules of Bruguiera spp. are spindle shaped because hypocotyl penetrates the seed coat and elongates (called as viviparous propagules). Matured propagules are purplish-green in colour which can be collected from water or plucked from trees. They can be directly planted in the selected locations by inserting them up to one-third of their length into the soil. Nursery-raised seedlings 20 to 30 cm height can be also used for outplanting. Direct planting of propagules are economical and less time consuming

Red 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".

Red Mangrove's Relationship with Humans

Rhizophora mucronata has multiple uses. It is used to help prevent coastal erosion and in restoration of mangrove habitats. The timber is used for firewood and in the construction of buildings, as poles and pilings, and in making fish traps. The fruits can be cooked and eaten or the juice extracted to make wine, and the young shoots can be consumed as a vegetable. The bark is used in tanning and a dye can be extracted from both bark and leaves. Various parts of the plant are used in folk medicine.

 In the Maldives, propagules are consumed after removing the skin and boiling them three to four times, first with ash to remove the bitterness and then with salt for taste. It is considered as a famine food and it was once planted in large areas in some islands, primarily for use during famine. It is also considered as a timber tree. Timber is hard and strong and used for boat building. Timber is normally buried in sand at the edges of the sea for about six months to prevent easy decay. Poles are used for house construction.

Red Mangrove habitat

This species is found in the intermediate to upstream estuarine zone in the lower to mid-intertidal region, and more to the seaward side. This species tolerates a maximum salinity of 40 ppt and a salinity of optimal growth of 8-33 ppt. (Robertson and Alongi 1992). This is a hardy species that is easily propagated and is fast-growing. It can grow up to 35 m, and can grow to 6 m high within seven years on plantations (Sukardjo and Yamada 1992).

In the eastern portion of its range, this species tends to grow closer to freshwater influences while in the western portion of its range it tends to grow closer to the seaward side. More genetic work is needed to determine if this may represent different species.

Red Mangrove threats

In South Andaman, 30-80% of Rhizophora spp. died due to continuous inundation after the 2004 Indian Ocean Tsunami in December 2004 (Roy and Krishnan 2005). 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.

Red Mangrove's status