The value of a mangrove area in Sarawak

Study Number:

4

Author:

E. L. Bennet & C. J. Reynolds

Abstract:

Many arguments have been presented to justify the conservation of tropical forests. In the case of mangrove forests, their preservation can be argued using economic and employment grounds alone. A case study of the Sarawak Mangroves Forest Reserve, Malaysia is presented. Here, the mangroves support marine fisheries worth US$21.1 million p.a. and up to 3000 jobs, timber products worth US$123,217 p.a., and a tourist industry worth US$3.7 million p.a. If the mangroves were to be damaged, all of the fisheries and timber and many of the tourism benefits would be lost. In addition, highly expensive civil engineering works would be incurred to prevent coastal erosion, flooding and other damage. The area is also one of the only remaining refuges for mangrove flora and fauna in Sarawak. If the area were to be converted to aquaculture ponds or oil palm plantations, levels of revenue would be greatly reduced, and the multiple other benefits of mangroves would be lost. Coastal land pressure is not a limiting factor in the State. Considering their economic, employment, coastal protection and species conservation values, mangroves should be conserved and their importance taken into account at all levels in coastal development planning.

Main Results and Conclusions:

• The specific species focused on in this paper include “…Avicennia spp., Rhizophora spp., Sonneratia spp. and Brugiera spp.”(361).
• The value of the study area is extensive and is broken up into the following categories: forestry, fisheries, tourism, conservation, and protection.

• Forestry: Residents of local villages use the mangrove forest for a variety of resources including: Nipa fronds for thatching, cigarette papers, and traditional cooking from Nypa fruticans, Nibong poles for prawn traps and house flooring from Onchosperma, and Bakau and Rhu for firewood from Rhizophora, and Casuarina equisetifolia (Chai, 1982; Bennett, 1987b).  In terms of commercial products extracted from the area, mangrove poles, charcoal, semi-charcoal, and cordwood all create a market value of US$ 123,217 (Sarawak Forest Department, unpublished data) (362). (Deforestation).
• Fisheries:  “The Sarawak Mangroves Forest Reserve is the last remaining large area of relatively intact mangrove in the Kuching Division… In terms of area, more than 95% of such mangrove in the Kuching Division occurs in this forest reserve. Thus, it supports almost the entire fisheries industry for the Division. The Divisional income from fisheries in 1989 was US$19.3 million, and it provided direct employment for nearly 3000 people (Marine Fisheries Department, 1989)… 363).

• Tourism: “The most important coastal tourism spots in Sarawak are all immediately adjacent to the Sarawak Mangroves Forest Reserve (363) (Coastal Development)… Complex stilt roots of mangrove trees trap silt and pollutants carried down by rivers from far inland. If the trees are cut (deforestation), silt is no longer trapped while the mangrove mud itself also destabilizes. The result is that water clarity is severely reduced, and a thick layer of anoxic mud is deposited on beaches over much of the coastline (de la Cruz, 1979; Anon., 1985). If this happened in the Sarawak Mangroves area, it would destroy the beaches and smother the coral reef immediately offshore… At a very minimum, half of the current income level would be lost, and the future potential tourist revenue would never be realized” (364).
• Conservation: the area of Sarawak “is a highly specialized habitat, and many of its species do not occur anywhere else”(364). Mangrove forests in the area are important for sustaining life of various monkey species as well as coral reefs in nearby and offshore marine parks.
• Protection: “Mangroves are vital in stabilizing shorelines, preventing erosion, tidal flooding and salt intrusion into neighbouring areas, and protecting beaches and corals from siltation (Table 5; IUCN, 1983; de la Cruz, 1979; WWF Malaysia, 1985; Working Group on Mangroves, 1986; Bennett, 1987a). All of these could become problems if the Sarawak Mangroves Forest Reserve were to be cleared” (366).
• The current threats to the park are prawn ponds, land for industry and housing, and possible threats from palm oil plantations. However, as discussed in the article, none of these options for mangrove forest replacement have greater benefits than the forest itself.

• Prawn Ponds: “…the natural fisheries productivity of mangroves is so high that it is seldom matched by that of artificial ponds”(370).
• Palm Oil Plantations: “…the revenue after deducing costs for fisheries is of the order of US$20 million year-1. For oil palm is it about US$1.67 million year-1” (370).
• Industry and Housing: “There are many other sites”-beside the mangrove forest reserve- “for industrial coastal development, including large areas of land heavily degraded due to intensive shifting agriculture. Thus, there are many alternatives to using the mangroves, which would not involve losses of their multiple benefits (Table 7). The same applies to use of the area for housing” (370).
• Recommendations: “Certain projects are highly productive and fully compatible with the functions of intact mangrove. One of these is floating cage aquaculture. This involves floating cages in which to cultivate fish within the rivers of a mangrove system. Unlike pond aquaculture, this does not involve any clearance of trees or disturbance of soils, so it does not damage existing fisheries or the environment” (371).

Works Cited:

Bennett, E. L. 1987a. The value of mangroves in Sarawak. Sarawak Gaz., 63: 12-21.

Bennett, E.L. 1987b. Use of the Sarawak Mangroves Forest Reserve by local residents: results of a survey of the kampungs in the area and recommendations to protect the area as a National Park. Kuching, Sarawak: National Parks and Wildlife Office, Forest Department.

Chai, P.P.K. 1982. Ecological studies of mangrove forest in Sarawak. PhD thesis, Universiti Malaya.

de la Cruz, A.A. 1979. The functions of mangroves. Proceedings of the Symposium on Mangrove and Estuarine Vegetation in Southeast Asia, pp. 125-38.

International Union for the Conservation of Nature (IUCN). 1983. Global Status of Mangrove Ecosystems (P. Saenger, E.J. Hegerl and J.D.S. Davie, eds). Commission on Ecology Paper No. 3. Gland, Switzerland: IUCN.

Marine Fisheries Department. 1989. Annual Report 1989. Sarawak: Marine Fisheries Department.

Working Group on Mangroves. 1986. Guidelines on the Use of the Mangrove Ecosystem for Brackishwater Aquaculture in Malaysia. The Working Group on Mangroves of the Malaysian National Mangrove Committee. Kuala Lumpur: Ministry of Science, Technology and Environment.

World Wildlife Fund (WWF) Malaysia. 1985. Proposals for a Conservation Strategy for Sarawak (complied by L. Chan, M. Kavanagh, Earl of Cranbrook, J. Langub, and D.R. Wells,). Kuala Lumpur: WWF Malaysia, Kuala Lumpur/Kuching, Sarawak: State Planning Unit of Sarawak.