Mangliye Rouz, Asiatic Mangrove, Rhizophora mucronata

Mangliye Rouz, Asiatic Mangrove, Rhizophora mucronata

Family: Rhizophoraceae

Scientific Name: Rhizophora Mucronata

English Name: Asiatic mangrove/Red mangrove/Loop-root mangrove

Creole Name: Mangliye Rouz

French Name: Manglier Rouge

IUCN Red List Status: Least Concern (LC)

Found throughout East Africa to the Indo-Pacific region.

Rarity in Seychelles: Least Concern (LC)

Mangroves make up at least 2,500 hectares of the Seychelles Archipelago. (Palacios et al. 2021). With regards to frequency, density and this is considered the most dominant species of mangrove in Seychelles. The highest density is found at Port Launay – the first Ramsar site declared in Seychelles located and also throughout the North-west coast of Mahé. On Praslin, a few isolated patches are still found at the mouth of rivers and inland in areas with brackish water such as Pasquiѐre. On the Outer islands, the mangrove forest Aldabra Atoll, which is also listed as a Wetland Site of International Importance under the Ramsar Convention is of the most significant along with the forests on Cosmoledo and Astove.

Origin: Indigenous (one of seven species of mangroves found in Seychelles).

Description:

Plants:

An evergreen tree with straight and sturdy bark that can grow up to 20 -25 metres tall. Distinct from other mangroves as it has long aerial roots or pneumatophores of at least two metres in length that bow and arch away from the tree. These roots help to absorb oxygen from the air, especially at low tide and keep the tree grounded despite the dynamic conditions of the intertidal currents that exist along coastal, estuaries and tidal flats.

Leaves:

Similar to other mangroves, the leaves of Rhizophora mucronata are adapted to the saline conditions with their large, dark and leathery texture as well as a layer of waxy hairs helping to reduce the loss of water. The leaves are branched opposite and are about 15 centimetres long with a distinct tiny white spike at the tip.

Seeds:

The fruits of the Rhizophora mucronata are round and brownish with a root-like or spear-shared hypocotyl that hangs upside down. The fruits are attached to the branch through its calyx. The early development of the seed whilst still attached to the parent tree makes it more buoyant, facilitating dispersal in water and viability. The shape of the seed, slightly swollen in the middle, is easily anchored in the muddy areas around the main tree where before long the leaves would grow from where the fruit has fallen off.

Flowers:

The flowers are quite fragrant with 4 whitish and hairy petals as well as 8 stamens. The Calyx are leathery and in pale green or creamy colour.

Propagation techniques:

This is considered a pioneer tree due to its efficient seed dispersal and thus colonizing new intertidal areas. However, in areas where rehabilitation is required, the mature seeds with brownish-green hypocotyl should be collected whilst still hanging from the tree. These can be planted immediately on the desired site or maybe immersed upright in brackish water until the pericarp falls off and the cotyledon starts appearing after 9 to 10 days. The seed should be immersed at least one-quarter to one-half in an area that has an influx and mixture of fresh, brackish or seawater throughout the year. Propagules of Rhizophora mucronata immersed in freshwater grew leaves faster whilst no apparent differences were noticed in root length for propagules immersed in either seawater and freshwater (Etongo et al., 2022). Young seedlings also provide food for crabs and other freshwater species and therefore successful re-introduction of propagules in an area demands regular maintenance. TRASS has introduced polystyrene tubes that help the seedlings to grow at a certain length so that they can withstand constant predation of their leaves and bark. Sites where this plant has been used by TRASS, is at Kot Dauban, on the way to L’Archipelle Hotel at Anse Gouvernment, Baie Ste Anne.

Uses:

The leaves and bark were used to turn into a red dye for the wooden floors of traditional houses in Seychelles. The ashes of burnt leaves were used to make soap whilst the sturdy and upright bark were used as posts.

Bibliographical references:

Beaver, K. (2008). Common Wild Plants of the Seychelles Coastal Lowlands. Ministry of Education and Culture, Seychelles. (08/09/2023).

Constance, A. (2017). Aldabra’s mangroves at the forefront of MSc thesis, Kapisen, Plant Conservation Action group. http://www.pcaseychelles.org/uploads/1/2/3/6/12369400/issue20.pdf (08/09/2023).

Etongo, D., D’Offay, K., Vel, T., Murugaiyan, P. and Henriette, E. (2022). Growth rate and survivorship of R. mucronata, A. marina, and C. tagal seedlings with freshwater and seawater treatment for mangrove propagation in nurseries. https://www.aloki.hu/pdf/2006_54095431.pdf (08/09/2023).

Government of Seychelles. (2019). Seychelles Wetlands Policy and Action Plan 2019-2022. https://faolex.fao.org/docs/pdf/sey202231.pdf (08/09/2023).

Hansen, G. Steen and Laboudallon, F. V. (2013). Flora of the Seychelles, A Field Guide to Selected Plants. Trykkeriet Friheden Aps. Denmark. (08/09/2023). 

Henriette, E. (2015). Biodiversity Assessment of the Port Launay mangrove, Mahé, Seychelles. http://www.s4seychelles.com/uploads/6/1/6/7/6167574/biodiversity_assessment_of_port_launay_mangrove_henriette_may__2015.pdf (08/09/2023).

Wikipedia. (2022). https://en.wikipedia.org/wiki/Rhizophora_mucronata (08/09/2023).

Ministry of Agriculture, climate change and environment. (2023). Wetlands ecosystem. https://macce.gov.sc/wetlands-ecosystem/ (08/09/2023).

Palacios, MM., Waryszak, P., Costa, MDP., Wartman, M., Ebrahim, A., Macreadie, P.I. (2021). Literature Review: Blue Carbon Research in the Tropical Western Indian Ocean WIO. A report submitted to the Seychelles Conservation & Climate Adaptation Trust (SeyCCAT). https://seyccat.org/wp-content/uploads/2020/01/BlueCarbonLab_LitReport_Seychelles_20210301_final.pdf (08/09/2023).

Ramsar Sites Information Service. (2004). Information Sheet on Ramsar Wetlands (RIS) Port Launay Coastal Wetland – Seychelles. https://rsis.ramsar.org/RISapp/files/RISrep/SC1432RISformer2005.pdf (08/09/2023).

Citation: Meriton-Jean, S. (2023). Mangliye Rouz, Asiatic Mangrove, Rhizophora mucronata. TRASS. www.trass.sc. https: // (08/09/2023).

TAGS: Praslin, mangroves, Seychelles, Aldabra, Rhizophora mucronata, Mangliye, Mangliye Rouz, propagation,