Samunsam Wildlife Sanctuary and proposed extensions
Location:
147'-2°00'N, 109°33'-l09°41'E; 85 km WNW of Kuching, bordered on the north and west by Indonesian Kalimantan, and to the east by the South China Sea, First Division,
Sarawak.
Area:
20,902 ha; present Wildlife Sanctuary 6,092 ha, proposed extensions 210 ha and 14,600 ha.
Altitude:
Sea level to 1,292m (Gunong Pueh).
Biogeographical Province:
4.25.12.
Wetland type:
01, 02, 03, 04, 05, 06, 07, 11, 12 & 21.
Description of site:
The entire water catchment area of the Samunsam River from the mangrove and nipa swamps of the lower reaches, through kerangas and mixed dipterocarp forest in the low-lying flat inland areas to the peaks of Gunong Malaka in the north, Gunong Puting in the east and Gunong Pueh in the south. The proposed Extension 1(210 ha) includes a number of offshore rocks and islands with breeding sea-birds. The mangrove areas are tidal, as are the lower reaches of the river for at least 13 km upstream from the rivermouth. Brackish water extends for about eight km upstream at spring tides. The mean tidal range is 3.0m.
Climatic conditions:
Humid tropical climate with an annual rainfall of 3,500-4,000 mm. The coastal zone is exposed to the northeast monsoon, and about 50-60% of the rainfall occurs during the monsoon, from November to February. The dry period extends from April to September, with June and July as the driest months. In the interior, the rainfall is more evenly distributed throughout the year. The average humidity at midday is 80%. Temperatures range from a minimum of about 21°C to a maximum of 34°C.
Principal vegetation:
Mangrove forest occurs along 6.5 km of Sungei Samunsam upstream from the rivermouth. Six types of mangrove forest have been recognized:
1. Rhizophora mucronata forest on sheltered, soft mud, with some R. apiculata. Ceriops tagal, Bruguiera parviflora and Aegiceras corniculatum.
2. Rhizophora apiculata forest on higher ground, associated with Bruguiera parviflora and B. gymnorhiza.
3. Bruguiera parviflora forest along river margins, associated with Ceriops tagal, Rhizophora apiculata and Xylocarpus granatum.
4. Sonneratia alba forest.
5. Nypa fruticans forest.
6. Oncosperma tigillaria forest, a transitional forest between true mangrove forest and freshwater swamp forest or Kerangas, dominated by the palm 0. tigiltaria. The associated species are mainly characteristic of freshwater swamp forest and include Bruguiera sexangula, Planohonella obovaza and species of Eugenia, Adinandra, Dillenia, Vatica, Diosuvios, Artocarpus, Mesua, Pongamia and Amnora.
Further inland, empran forest occurs in low-lying areas subject to seasonal flooding. This forest is characterized by its dense undergrowth; the common large trees are species of Shorea, Hopea, Knema, Sterculia, Aglaia, Kibessia, Eugenia and Garcinia. Mixed dipterocarp lowland rainforest and kerangas forest occur in the drier areas.
Land tenure:
State owned (Sarawak State Government); some areas are under Native Customary Rights.
Conservation measures taken:
The lower half of the Samunsam River is protected within the Samunsam Wildlife Sanctuary (6,092 ha), gazetted in 1979. Gunong Pueh Forest Reserve covers the southern part of site. The Wildlife Sanctuary was established primarily to protect its large population of the Proboscis Monkey Nasalis larvatus.
Conservation measures proposed:
Two additional areas, totalling 14,810 ha, have been proposed as extensions to the Samunsam Wildlife Sanctuary. Extension I (210 ha) includes a number of offshore rocks and islands; Extension II (14,600 ha) includes the Gunong Pueh Forest Reserve. Extension of the existing sanctuary would bring the whole river system under the control of the sanctuary and should bring about an improvement in water quality in the Sungei Samunsam, as the area gradually recovers from logging operations upstream. The proposed extensions would protect the rich forest to the north of the Samunsam River, control the main access to the sanctuary and increase the number of Sarawak's protected animal species occurring in the sanctuary from 12 to 19.
Land use:
Gunong Pueh Forest Reserve is currently being logged. The exploitation of nipa palms is permitted in a small prescribed zone within the existing Wildlife Sanctuary. Surrounding mangrove forests are under licence for extraction of poles and firewood, and nipa is also cut. Agriculture and fishing are the main activities in adjacent areas.
Possible Changes in Land use:
No information.
Disturbances and threats:
A major threat is clearance of kerangas forest for agricultural land. The use of mangrove wood for poles, charcoal and building materials is a further disturbance. The water quality of the Sungei Samunsam has been adversely affected by logging operations further upstream. Logging continues in Gunong Pueh Forest Reserve outside the present boundaries of the Wildlife Sanctuary. Two related projects pose a direct threat to the Samunsam Wildlife Sanctuary: a transmission line from the proposed Bakun Hydro to Peninsular Malaysia, and a road providing access to the transmission line and associated settlements. Routing of the transmission line and road as currently proposed would split the Proboscis Monkey population into two units, thereby threatening its long-term survival, and would provide access for illegal hunters. Many other wildlife species would be similarly threatened. The problems would be minimized if the transmission line and road were positioned within 500m of, and parallel to, the coast.
Economic and social values:
The mangrove swamps support an important fishing industry, and provide a source of timber and charcoal.
Fauna:
MacKenzie (1981) has listed twenty-four species of freshwater fishes for the area. At least 240 species of birds have been recorded in the Wildlife Sanctuary, including approximately 50 species of waterbirds. The latter include Anhinga melanogaster, Ixobrychus eurhythmus, Egretta eulophotes, Ardea sumatrana, Ciconia stormi, Charadrius peronii (breeding), many other shorebirds and several species of terns. In 1986, a breeding colony of terns on the rocks off Kuala Samunsam included at least 37 pairs of Sterna sumatrana and four pairs of S. anaethetus. About 90 adult S. sumatrana and 12 adult S. anaethetus were associated with the colony.
Seventy species of mammals have been recorded in the Wildlife Sanctuary, including four rare primates: the Proboscis Monkey Nasalis larvaltus, the langurs Presbytis cristata and P. melalophos chrysomelas (both endangered in Sarawak), and the Bornean Gibbon Hylobates muelleri (vulnerable in Sarawak and protected under the Wild Life Protection Ordinance). The population of N. larvatus was estimated at about 160 individuals in 1986, making this the largest known population of the species in Sarawak. Other mammals include the dolphins Sotalia plumbea, S. borneensis; the otters Lutra sumairana, Ambi onyx cinerea; and the Dugong Dugong dugon.
Thirty-five species of reptiles and 20 species of amphibians have been recorded. The Sanctuary supports breeding populations of Orbitia borneensis (Testudinae) and the marine turtles Chelonia mydas and Caretta caretta. The Estuarine Crocodile Crocodylus porosus and the Painted Terrapin Callagur borneensis have been reported in the Samunsam River. Complete lists of the fishes, amphibians, reptiles, birds and mammals known to occur in the Wildlife Sanctuary are given by MacKenzie (1981) and Basiuk (1985).
Special floral values:
The area contains an unusually wide variety of mangrove forest types. Several rare and vulnerable plant species have been recorded, including Licuala bintuluensis, Rhododendron variolosum. Areca borneensis and Salacca sarawakensis.
Research and facilities:
The fauna and flora of the Wildlife Sanctuary have been well documented. Research was carried out on the Proboscis Monkeys in 1979-1981 (Salter et al., 1985) and 1984-1986 (Bennett, 1986), and a crocodile survey was conducted in July 1985.
References:
Basiuk (1985); Bennett (1986 & undated); Cox & Gombek (1985); Department of Agriculture (1982a); DID Sarawak (1979/80); DUN Special Select Committee on Flora and Fauna (1986); MacKenzie (1981); National Parks and Wildlife Office (1985); Salter & MacKenzie (1981); Salter et al. (1985).
Criteria for Inclusion:
1b, 2a, 2b, 2c, 3b.
Source:
National Parks and Wildlife Office (Sarawak Forest Department) and E.L. Bennett.