Mangrove



Mangroves are a group of shrub and tree species that live along shores, rivers and estuaries in the tropics and subtropics.1 Mangroves are resilient. They are able to withstand the brunt of flooding, ocean-borne storms and hurricanes. They also have the ability to survive in conditions ranging from muddy soil to coral rock, as well as in water up to 100 times saltier than what most other plants can tolerate.

Background
The term mangrove is said to have been derived from manggi-manggi and el gurm, which are Malay and Arabic words respectively for a type of mangrove tree known as Avicennia, which when combined become “mang-gurm ”. While the term mangrove may be used interchangeably to refer to a species, plant or forest, it is often used to collectively describe the unique ecosystem.3

In the 1820s, mangroves made up 13 percent of Singapore’s total land area. Today, only 0.5 percent remains, and much of these are in military or state land.4 On mainland Singapore, mangroves can be found in the north, in areas like Lim Chu Kang, Kranji and Mandai, as well as nature reserves and parks such as the Sungei Buloh Wetlands Reserve and Pasir Ris Park. There are also mangroves on some offshore islands such as Pulau Semakau, Pulau Tekong and Pulau Ubin.5


Biology

Mangrove species are broadly classified into two major categories. Species that are found exclusively in tropical intertidal habitats are “true mangrove” species, while “mangrove associates” are species that are not exclusive to this habitat. Of the 70 true mangrove species recognised in the world, 35 may still be found in Singapore, with only one confirmed extinct species, the Brownlowia argentata.6 The two most common mangrove species in the local ecosystem are the bakau minyak (Rhizophora apiculata) with their characteristic prop or stilt roots attached to the trunk, and the bakau putih (Bruguiera cylindrica) with their lateral roots sticking out of the mud surface resembling a person’s bent knees.7

Mangroves are known for their morphological adaptation to their wetland environment. One example is vivipary, a condition where the fruit germinates while still attached to the plant; once matured, the seedlings fall and are dispersed by the tide to grow at some distance from the parent tree. Another example is pneumatophores, or specialised aerial breathing roots, which anchor the trees to the unstable anaerobic soil and provide air to the underground root system.8

Another key attribute of mangroves is their ability to withstand fluctuating saline conditions and thrive in the inter-tidal seawater.9 As high salt levels will lead to death, mangrove plant species such as the Rhizophora have a physiological mechanism for salt exclusion by filtering the solutions they come into contact with. Others, such as the Aegiceras corniculata, secrete the absorbed salt through their leaves using special glands, which are then removed by wind or rain.10

The mangrove ecosystem
Mangroves are rich ecological habitats for many animals, and serve as important nursery grounds and breeding sites for birds, insects, spiders, fishes, crustaceans, shellfish, reptiles and mammals.11 The intertidal zone flourishes with hardy tiger seagrass (Halophila beccarii), bivalves like mangrove tree oysters (Isognomon ephippium), edible “coffin nail” telescope snails (Telescopium telescopium), as well as casts of fiddler crabs and air-breathing fishes such as mudskippers.12 The shy and nocturnal mud lobsters (Thalassina anomala) make their home in mangroves by building mud mound systems with their huge mandibles. The mud mounds also serve as microhabitats for other life forms such as the moss-like mangrove liverwort (Lepidozia mamillosa) and the intertidal ant (Odontomachus malignus).13 In addition, avian visitors such as the Pacific golden plover (Pluvialis fulva) and endangered Chinese egret (Egretta eulophotes) use Singapore’s mangroves as mid-journey stops for rest and recovery during their migration journeys.14

The food chain in mangroves is complex and diverse. Humans sit at the very top of this food chain, harvesting wood, charcoal, medicine and seafood.15 Other notable top predators include the Malayan water monitor (Varanus salvator), the venomous banded krait (Bungarus fasciatus), as well as the critically-endangered man-eater, the estuarine crocodile (Crocodylus porosus).16

Otters, a mangrove resident that was once rare in Singapore, have also been increasingly sighted in places such as Bishan, East Coast Park and Marina Bay.17

Species found in Singapore mangroves include the highly venomous shore pit viper (Trimeresurus Purpureomaculatus), discovered in 1832, which gives birth to live young instead of laying eggs; and the now-endangered rose fiddler crab (Uca rosea), which was discovered in 1937.18 Local researchers continue to make discoveries in Singapore’s mangroves, such as the tiger-striped tigger shrimp (Potamalpheops tigger) in 1997, and the 1998 new classification of the “tree-hugging crab” Moguai aloutos.19

Economic value
Mangroves play a vital role in coastal protection by preventing shoreline erosion, reducing sedimentation in coastal waters, absorbing pollutants and improving soil chemistry.20 In addition, there is growing evidence that mangroves also provide some protection against the destructive forces of natural disasters such as hurricanes and tsunamis. In the Indian Ocean tsunami of December 2004, communities living near large mangrove forests suffered significantly less damage compared to areas where mangroves had been cleared or degraded.21

With the growing awareness of climate change, there is rising interest in exploring mangroves as a source of “carbon sinks” for reducing carbon dioxide emissions, which is a root cause of climate change.22 It has been estimated that Singapore’s remaining mangrove patches may store 450,570.7 megagrams of carbon, which may be equivalent to the average annual carbon emissions of 621,000 residents.23

Mangroves were once widely exploited for fuelwood as mangrove wood has high calorific value. It is still a preferred choice of timber for construction due to its strength and high resistance to insects, rot and salt water.24 The nipah palm (Nypa fruticans) – the only true mangrove palm in Singapore – has numerous uses. The attap chee used in local deserts are its seeds preserved in heavy syrup, while its sap can be used for making toddy, vinegar or palm sugar (gula melaka). In addition, its leaves have been used to make thatched huts, baskets, mats and brooms.25 Many of the mangrove plants have also been featured in local medicine folklore. For example, the sap of the sea derris (Derris trifoliata) has been used as fish poison, while the leaves of the mata ayam (Ardisia elliptica) are boiled and consumed for heart pain.26

The mangrove is a major source of food, especially seafood such as fishes, prawns, crabs and shellfish. Some of the well-known seafood found in mangroves include the blood cockle (Anadara granosa), mangrove mud crab (key ingredient for Singapore’s national dish chilli crab), tiger prawn (Penaeus monodon) and sea bass or barramundi (Lates calcarifer). Mangroves used to be a food source for local villagers. Today, with large-scale farming practices, most of these food supplies are imported from neighbouring countries into Singapore.27

Conservation efforts
From the founding of modern Singapore in 1819 till present day, mangroves have been cleared for various reasons – realignment and concreting of rivers, industrial estate developments, aquaculture farming of fish and prawns, reservoir construction, housing developments, and land reclamation schemes.28 A classic example is the reclamation of large tracts of mangrove in Jurong into the Jurong industrial area.29

The National Parks Board (NParks) is responsible for the conservation of Singapore’s biodiversity. Working with various conservation communities under the 2015 Nature Conservation Masterplan, NParks oversees the physical conservation of nature reserves, biodiversity research, as well as conservation activities such as species recovery of the berus mata buaya (Bruguiera hainesii) – one of the most endangered mangrove tree species in the world.30


Conservation efforts require ongoing support and sponsorship from the community. Recent examples include a fundraising campaign by Tokio Marine Life Insurance Singapore to support the planting of mangrove saplings at the Sungei Buloh Wetland Reserve, as well as a donation of S$500,000 by Kikkoman Singapore for the establishment of a mangrove arboretum at the reserve’s Coastal Trail for mangrove conservation, education and public outreach.31 In addition, regular events such as the annual International Coastal Cleanup help to raise local awareness on nature conservation, especially among students.32 Commercial interest towards nature conservation has also risen, with specialist eco-tours offering nature appreciation tours and mangrove kayaking.33



Author

Nureza Ahmad



References
1. American Museum of Natural History. (2004, May). Mangroves: The roots of the sea. Science Bulletins. Retrieved 1 Jun 2017 from American Museum of Natural History website: http://www.amnh.org/explore/science-bulletins/bio/documentaries/mangroves-the-roots-of-the-sea/what-s-a-mangrove-and-how-does-it-work/
2. American Museum of Natural History. (2004, May). Mangroves: The roots of the sea. Science Bulletins. Retrieved 1 Jun 2017 from American Museum of Natural History website: http://www.amnh.org/explore/science-bulletins/bio/documentaries/mangroves-the-roots-of-the-sea/what-s-a-mangrove-and-how-does-it-work/; Chua, E. K. (2010). Wetlands in a city: The Sungei Buloh Wetland Reserve. Singapore: Simply Green, p. 83. (Call no.: RSING 333.918095957 CHU)
3. Ng, P. K. L., & Sivasothi, N. (Eds.). (1999). A guide to the mangroves of Singapore 1: The ecosystem and plant diversity. Singapore: Singapore Science Centre, p. 5. (Call no.: RSING 577.698095957 GUI)
4. Chua, E. K. (2010). Wetlands in a city: The Sungei Buloh Wetland Reserve. Singapore: Simply Green, p. 83. (Call no.: RSING 333.918095957 CHU); Thiagarajah, J., et al. (2015, November). Historical and contemporary cultural ecosystem service values in the rapidly urbanizing city state of Singapore. Ambio, 44(7), 666–677, p. 668. Retrieved from ProQuest via NLB’s eResources website: http://eresources.nlb.gov.sg/
5. Chua, E. K. (2002). Chek Jawa: Discovering Singapore’s biodiversity. Singapore: Simply Green, p. 41. (Call no.: RSING 333.91716 CHU); Ng, P. K. L., & Sivasothi, N. (Eds.). (1999). A guide to the mangroves of Singapore 1: The ecosystem and plant diversity. Singapore: Singapore Science Centre, pp. 10, 30. (Call no.: RSING 577.698095957 GUI)
6. Polidoro, B. A., et al. (2010). The loss of species: Mangrove extinction risk and geographic areas of global concern. PLOS ONE, 5(4), 1–10, p. 2. Retrieved from EBSCOhost via NLB’s eResources website: http://eresources.nlb.gov.sg/; Yang, S., et al. (2011, October 16). The current status of mangrove forests in Singapore. Proceedings of Nature Society, Singapore’s Conference on ‘Nature Conservation for a Sustainable Singapore’, 99–120, p. 101. Retrieved 1 Jun 2017 from Nature Society (Singapore) website: https://www.nss.org.sg/documents/Pages%2099-120.%20Yang%20et%20al.,%202013.%20Singapore%20Mangroves.pdf
7. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, pp. 30–36. (Call no.: RSING 578.7698095957 PRI)
8. Ng, P. K. L., & Sivasothi, N. (Eds.). (1999). A guide to the mangroves of Singapore 1: The ecosystem and plant diversity. Singapore: Singapore Science Centre, pp. 26, 82–86. (Call no.: RSING 577.698095957 GUI)
9. Ng, P. K. L., & Sivasothi, N. (Eds.). (1999). A guide to the mangroves of Singapore 1: The ecosystem and plant diversity. Singapore: Singapore Science Centre, p. 26. (Call no.: RSING 577.698095957 GUI)
10. Ng, P. K. L., & Sivasothi, N. (Eds.). (1999). A guide to the mangroves of Singapore 1: The ecosystem and plant diversity. Singapore: Singapore Science Centre, pp. 81–82. (Call no.: RSING 577.698095957 GUI); Chua, E. K. (2002). Chek Jawa: Discovering Singapore’s biodiversity. Singapore: Simply Green, p. 36. (Call no.: RSING 333.91716 CHU)
11. Nature Society (Singapore). (2003). Singapore waters: Unveiling our seas. Singapore: Nature Society Singapore, Marine Conservation Group, pp. 45–56. (Call no.: RSING q578.77095957 SIN); Chua, E. K. (2010). Wetlands in a city: The Sungei Buloh Wetland Reserve. Singapore: Simply Green, pp. 82–83. (Call no.: RSING 333.918095957 CHU)
12. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, pp. 92–130. (Call no.: RSING 578.7698095957 PRI)
13. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, pp. 46–62. (Call no.: RSING 578.7698095957 PRI)
14. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, pp. 143–158. (Call no.: RSING 578.7698095957 PRI)
15. Ng, P. K. L., & Sivasothi, N. (Eds.). (1999). A guide to the mangroves of Singapore 1: The ecosystem and plant diversity. Singapore: Singapore Science Centre, pp. 41–50. (Call no.: RSING 577.698095957 GUI)
16. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, pp. 168–170. (Call no.: RSING 578.7698095957 PRI)
17. Lee, M. K. (2016, August 11). ‘Otterly’ cute National Day gift on YouTube: Video opens with Bishan’s famous otter family and gives a glimpse into wild otter population. The Straits Times; Wee, L. (2016, July 24). Mad about otters: Enthusiasts look out for charming animals: A community of enthusiasts look out for, and watch over, the charming animals. The Straits Times. Retrieved from ProQuest via NLB’s eResources website: http://eresources.nlb.gov.sg/
18. Chua, E. K. (2010). Wetlands in a city: The Sungei Buloh Wetland Reserve. Singapore: Simply Green, p. 136. (Call no.: RSING 333.918095957 CHU); Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, p. 211. (Call no.: RSING 578.7698095957 PRI)
19. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, pp. 210–212. (Call no.: RSING 578.7698095957 PRI)
20. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, p. 225. (Call no.: RSING 578.7698095957 PRI)
21. Barbier, E. B. (2006, April). Natural barriers to natural disasters: Replanting mangroves after the tsunami. Frontiers in Ecology and the Environment, 4(3), 124–131, p. 124. Retrieved from JSTOR via NLB’s eResources website: http://eresources.nlb.gov.sg/
22. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, p. 226. (Call no.: RSING 578.7698095957 PRI)
23. Friess, D. A., et al. (2016, June). Mangrove forests store high densities of carbon across the tropical urban landscape of Singapore. Urban Ecosystems, 19(2), 795–810, p. 795. Retrieved from ProQuest via NLB’s eResources website: http://eresources.nlb.gov.sg/
24. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, p. 31. (Call no.: RSING 578.7698095957 PRI); Chua, E. K. (2010). Wetlands in a city: The Sungei Buloh Wetland Reserve. Singapore: Simply Green, p. 83. (Call no.: RSING 333.918095957 CHU); Nature Society (Singapore). (2003). Singapore waters: Unveiling our seas. Singapore: Nature Society Singapore, Marine Conservation Group, p. 45. (Call no.: RSING q578.77095957 SIN)
25. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, p. 219. (Call no.: RSING 578.7698095957 PRI); Nature Society (Singapore). (2003). Singapore waters: Unveiling our seas. Singapore: Nature Society Singapore, Marine Conservation Group, p. 45. (Call no.: RSING q578.77095957 SIN)
26. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, pp. 5, 20. (Call no.: RSING 578.7698095957 PRI)
27. Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, pp. 192–200. (Call no.: RSING 578.7698095957 PRI)
28. Tan, H. T. W., et al. (2007). The natural heritage of Singapore. Singapore: Pearson/Prentice Hall, p. 72. (Call no.: RSING 508.5957 NAT)
29. Barnard, T. P. (Ed.). (2014). Nature contained: Environmental histories of Singapore. Singapore: NUS Press, p. 44. (Call no.: RSING 304.2095957 NAT); Nature Society (Singapore). (2003). Singapore waters: Unveiling our seas. Singapore: Nature Society Singapore, Marine Conservation Group, p. 46. (Call no.: RSING q578.77095957 SIN)
30. National Parks Board (2015, June 27). Nature Conservation Masterplan (NCMP). Retrieved 2016, October 30 from National Parks website: https://www.nparks.gov.sg/news/2015/6/nature-conservation-masterplan; Ng, P. K. L., Wang, L. K., & Lim, K. K. P. (Eds.). (2008). Private lives: An exposé of Singapore’s mangroves. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, p. 203. (Call no.: RSING 578.7698095957 PRI)
31. National Parks Board. (2016). Green matters: Annual report 2015/16. Singapore: Author, pp. 32–42. Retrieved 1 Jun 2017 from National Parks website: https://www.nparks.gov.sg/~/media/nparks-real-content/about-us/annual-report/2015-2016-annual-report-high-res.pdf
32. About the International Coastal Cleanup. (n.d.). Retrieved 2016, November 1 from International Coastal Cleanup, Singapore website: http://coastalcleanup.nus.edu.sg/aboutcleanup.html
33. Wee, L. (2016, October 30). Go on an eco-tour in Singapore. The Straits Times. Retrieved from ProQuest via NLB’s eResources website: http://eresources.nlb.gov.sg/



The
information in this article is valid as at 2017 and correct as far as we are able to ascertain from our sources. It is not intended to be an exhaustive or complete history of the subject. Please contact the Library for further reading materials on the topic.

Subject
Mangrove swamps--Singapore
Mangrove plants--Singapore
Science and technology>>Botany>>Plant ecology
Plants
Nature>>Plants