The Lower Reaches of the Baram River System
Location:
3°42'-4°36'N, 113°59'-114°36'E; 100 km southwest of Bandar Sen Begawan on the Brunei-Sarawak border, Fourth Division, northeastern Sarawak.
Area:
c.300,000 ha.
Altitude:
0-15m.
Biogeographical Province:
4.25.12.
Wetland type:
07, 11, 13, 14, 15 & 21.
Description of site:
A major river with a large catchment area; the river is sluggish in its lower reaches and forms a series of large oxbows and five small lakes. There are large areas of peat swamp forest on the adjacent flood plain. The river course is congested with floating vegetation, and there is a small area of estuarine mangrove forest and nipa swamp near the river mouth. The Baram flood plain has extended as the sea-level has fallen, the peat swamps overlying a clay subsoil. The most highly developed peat swamps in Sarawak occur in the Baram river system, upstream from Kuala Bakong. Lubok Pasir peat swamp has been aged at about 4,270 years. It has a steeply domed surface and a maximum recorded depth of 11 .9m. The peat swamp at the confluence of the Baram and Tinjar rivers also has a highly developed domed surface. The water table is very close to the surface of the swamp, and run-off is rapid. The domed peat swamp areas have radial surface drainage. Water levels fluctuate by up to 4.5m at Marudi and 2.5m at Kuala Baram. Two key areas within the site, namely Sungei Karap and Loagan Ungar, are described separately below (sites 27a and 27b).
Climatic conditions:
Humid tropical climate with an annual rainfall of 3,000-4,000 mm. The region is markedly drier than coastal areas, and has a marked dry season from June to October, which appears to restrict extensive formation of freshwater swamps.
Principal vegetation:
There are some small patches of mangrove forest and nipa swamp along the lower Baram River. The oxbows and small lakes are thickly fringed with floating plants, Hanguana sp, Scleria sp and ferns. The middle Baram River flows through an extensive area of swamp forest, and is bordered by cane grass Saccharum robustum. Some of the tributaries, especially the Sungei Karap, are overgrown with floating vegetation. There are two main types of swamp forest forest with dense, pole-like stands of trees 15-21 m tall, dominated by Litsea sp, Cratoxylon glaucum, Calophyllum obliquinervum and Compretocarpus rotundatus, and an open savannah type of forest in which the trees are scattered and stunted.
Land tenure:
State owned.
Conservation measures taken:
The entire area is included within State Forest Reserves.
Conservation measures proposed:
It has been recommended that complete protection be given to at least one representative example of a Baram oxbow lake. The Loagan Bunut area (10,740 ha) has been proposed as a National Park, and the proposal is being given high priority. The Sarawak State Conservation Strategy has recommended that ecological surveys be undertaken to assess the resource potential and to determine the environmental requirements of Loagan Bunut and the Baram oxbows. The State Conservation Strategy has also recommended that the exploitation of the Tapah Wallago maculatus be monitored and controlled. The potential of the site for designation as an International Biosphere Reserve should be investigated. An environmental impact assessment of the proposed Batang Baram Flood Mitigation project should be carried out, and ecological considerations fully taken into account before the project is approved.
Land use:
Intensive fishing in some areas, such as Loagan Payau and Loagan Teraja, and agriculture (gardens and plantations) upstream from the brackish zone. The Bakong tributary is heavily utilized for fishing and logging, and Sungei Bunut is heavily fished during the dry season by local villagers. There is some shifting cultivation in surrounding areas.
Possible Changes in Land use:
There are plans to drain an extensive portion of the Bird Sanctuary in the Kerah Swamp area. Under the Fifth Malaysia Plan (starting in 1986/87), a pumping station is to be installed to reduce surface water, and under the Sixth Plan (1990/95), more drainage canals are to be constructed. The Aquabio Prawn Farm is to be expanded from its existing 40 ha to 4,000 ha, at the expense of open grazing land.
Disturbances and threats:
The Batang Baram Flood Mitigation project proposed by the Department of Drainage and Irrigation would involve the clearance of riverine swamp forest, and would significantly alter water flow in the middle and lower Baram. The project still requires funding before it can proceed. The middle Baram is the only area in the system where crocodile hunting (i.e. gathering of young) is acknowledged to continue. The lower Baram is heavily used by boat traffic, which causes a considerable amount of disturbance to crocodiles. Sungei Tinjar and Sungei Teru are reported to be much disturbed by shifting cultivation and fishing. The Tapah Wallago maculatus is very vulnerable to wanton slaughter when it enters small tributaries along the Baram for spawning. Loagan Bunut is at risk from logging in its catchment area, and from proposed agricultural developments upstream. The Baram oxbows are vulnerable to pollution from proposed development projects nearby.
Economic and social values:
The oxbow lakes are important breeding grounds and nursery areas for commercially valuable fish species. The domed surfaces of the peat swamps reduce the extent of local flooding; the steep doming of the swamp surface near the confluence of the Baram and Tinjar rivers probably reduces flooding to less than 400m except along streams. The site is of considerable interest for scientific research as it incorporates a vast expanse of peat swamp forest, including the most highly developed peat formations in Sarawak, along with good examples of mangrove forest, oxbow lakes and temporarily flooded forest.
Fauna:
A total of 43 species of fishes have been recorded (DUN Special Select Committee on Flora and Fauna, 1985). The Biawan Helostoma temmincki has invaded many of the lakes of the lower Baram. This species forms a major part of the fish catch, but is not favoured by fishermen. The area is particularly important for the Estuarine Crocodile Crocodylus porosus, which is widely distributed in very low numbers throughout the middle and lower Baram system. Twenty-four C. porosus were located during a survey of 335 km of river in 1985. Most of the crocodiles were concentrated in the middle reaches of the main river, and were thought to breed at Loagan Tebaboi and Loagan Baru. There are also unconfirmed reports of the endangered False Gharial Tomistoma schlegelii at Loagan Bunut on the Tinjar River. A tree monitor Varanus heteropholis is known only from the middle Baram, and presumably still occurs there. Other rare reptiles which may occur in the area include the Burmese Brown Tortoise Geochelone emys and Painted Terrapin Callagur borneoensis.
Special floral values:
The most highly developed peat swamp formations in Sarawak occur upstream from Kuala Bakong. Nepenthes bicalcarata occurs in the peat swamp forest and is considered to be a vulnerable species in need of special protection. The rare N. rafflesiana occurs in peat swamp forest and mossy forest, and also merits special protection.
Research and facilities:
Several forest inventories and a soil survey have been carried out (Department of Agriculture, 1982c), and the Forest Department has established a research plot at the site. A preliminary survey of the crocodile population was conducted in July-September 1985 (Cox & Gombek, 1985).
References:
Anderson (1964); Brunig (1962); Chai (1962); Cox & Gombek (1985); Department of Agriculture (1982c); DID Sarawak (1979/80 & 1986); DUN Special Select Committee on Flora and Fauna (1985 & 1986); Sarawak Marine Fisheries Department (undated-a & undated-b); Watson (1985); Wood (1967 & 1971); WWF Malaysia & State Planning Unit of Sarawak (1985); Yong (1967a & 1967b); Yusof & Cheong (1976).
Criteria for Inclusion:
1b, 2a, 2b, 3b.
Source:
Sarawak Department of Drainage and Irrigation, and Sarawak Forest Department.