Bako-Buntal Bay

Year of compilation: 2003

Site description (baseline)
The site encompasses the twin promontories that form the donkey-ears of Kuching. The western promontory is Gunung Santubong, and the eastern promontory the sandstone plateau of Bako National Park. Between these is the Bako-Buntal Bay, an expanse of inter-tidal mudflats fringed with mangrove forest. Numerous rivers flow into the sea, the major ones being Sg. Sarawak and Sg. Bako, emerging on either side of the Bako plateau and Sg. Buntal and Sg. Santubong, emerging either side of Gunung Santubong. This vast delta constitutes the Sarawak Mangroves, the most extensive mangrove forest in western Sarawak. The descriptions of this IBA are divided into three parts: Gunung Santubong, Bako-Buntal Bay and Bako National Park. (I) Physical CharacteristicsSantubong: An 810m sandstone mountain, connected to the mainland by a narrow (not more than 1.5km) strip of land. The coastline is rocky, with small sandy coves. The western side of the mountain is rises steeply, covered with mixed dipterocarp forest. The eastern side has gentler slopes, with heath forest grading into MDF higher up. Above 600m, vertical cliff faces are exposed in areas. The top is narrow and deeply incised in parts, forming crevices. Numerous clearwater streams flow down its slopes, forming cascades. The rocky shoreline shows weathering on the west, exposing rock and boulder beds during low tides. The eastern side is less weathered, probably a result of the sheltering effect of the bay. Less exposure is evident during low tides.The tall forest has never been commercially logged, but illegal extraction of larger trees is rampant. The lower slopes along the western side have been developed into a resort city, with numerous hotels, outdoor recreational facilities, sea-facing golf courses and the world renowned Sarawak Cultural Village are located here. Numerous trails extend into the forest, including a trail to the summit. The eastern side remains un-developed.Bako-Buntal Bay: a semi-circular bay bordered by Gunung Santubong to the west and Bako National park to the east. Roughly 15km wide between the promontories, narrowing to less than 5km between the Sg. Bako and Sg. Buntal at its base. Mangrove forest stretches between the two promontories. The bay is shallow, consisting of a sandy substrate overlaid with mud closer to the estuaries. The inter-tidal environment is dynamic, with constantly shifting sandbars. During very low tides, almost a third of the bay is exposed sandflats and mudflats. The October to February monsoon causes rough weather in the bay, and the mangrove shoreline is being seriously affected by erosion. On the eastern side, areas of mangrove have been cleared for aquaculture farms.Bako NP: Bako National Park is Sarawak's oldest national park to protect rocky coastlines, which are rare in the State, and unusual landscapes with scenery of exceptional beauty. It lies on the Muara Tebas Peninsula, which faces the South China Sea. The national park is formed from a sandstone plateau covering the northern part of the headland. Thick layers of white to pale buff sandstone, which lie in almost horizontal position, build up the plateau. The sandstone is coarse to medium-grained and contains scattered pebbles of quartz and chert. Conglomerates, consisting of rounded pebbles and grains in a sandy matrix, are abundantly present. Thin layers of mudstone are occasionally seen between the sandstone beds. These rocks attain a thickness of at least 290 m and are called the Plateau Sandstone Formation (Good, 1988; Tan, 1993). Several hills are situated on the plateau and the highest is Bukit Gondol (260 m asl). Soils on the plateau range from coarse sand to clay and from thick to thin. The soil composition in the national park depends to a large extent on the type of rocks underlying the soil. Soils on low-lying areas include riverine or alluvial soils, mangrove soils, podsols and red-yellow pozolic soils (Brunig, 1974).(II) Climatic ConditionsThere is a marked seasonal climate in the area. Annual rainfall of about 4,300 mm is concentrated during the wet season from November-February. The average rainfall during May-September is less than 200 mm per month. Temperature ranges between 20oC-30oC (Good, 1988).

Key biodiversity
Malaysian Plover Charadrius peronii, Far Eastern Curlew Numenius madagascariensis, Asian Dowitcher Limnodromus semipalmatus (Croxall 1969; Gregory-Smith, 1996, 1995; Jeyarajasingam et al., 2001a; Sebastian, 2003; Smythies, 1999; Yeap et al., 2003)The bay is of global importance as a wintering site for waterbirds. It is also a historical site, with continuous observations dating back to the early 1900s. (From historical records, we know that in February, 1913, Spotted Greenshanks Tringa guttifer were seen at Buntal, in 1935, Far-eastern Curlews Numenius madagascariensis were described as swarming at Buntal; and on 9 June 1958, a single Eurasian Curlew Numenius arquata was seen at Buntal).Eleven heron species occur, including a large mixed wintering population of Great, Intermediate and Little Egrets. 31 Chinese Egrets were counted in the Bay in 2003. This number qualifies as 1% of the global population under the Ramsar criteria. This may be the largest number recorded to date on Borneo, the previous totals being 13 in Dec 1984 and 15-25 in April 1986 in Brunei (Smythies, 1999). Birdlife International (2001) postulates that a small but not insignificant proportion of the world's population is dispersed along the coastline of Borneo and Sulawesi between October and March each year, and that the species may have been a common winter visitor in Sarawak in the 1890s.32 shorebird species have been recorded in the bay to date, the most common being Great Knot (986), Greater Sand Plover (1,040), Lesser Sand Plover (1,167), Grey Plover (467) and Red Knot (409). An estimated 20-25,000 waterbirds winter in the bay and its immediate environs. The most significant species are regular usage by Spotted Greenshank, Asiatic Dowitcher and Far Eastern Curlew, the latter in significant numbers (200 in 2003). Numbers of Red Knot and Great Knot are among the highest for any site in Malaysia.Eleven species of terns have been recorded, including a historical occurrence of Chinese Crested Tern.Bako NP: One hundred and fifty species of birds have been identified in the park (Good 1988; Sreedharan 1987; Radcliffe and Tyler 1984). Passage migrants and winter visitors have been noted using the coastal areas of the park in surveys (Croxall, 1969; Edwards and Polshek 1987) such as the Spotted Greenshank Tringa guttifer. Bako National Park is an important site for biome-restricted birds supporting 56 lowland forest species (3 Vulnerable, 24 Near Threatened) and one montane forest species. Other Near Threatened birds such as Malaysian Plover Charadrius peronii (resident), Far Eastern Curlew Numenius madagascariensis and Gould's Frogmouth Batrachostomus stellatus has also been recorded from the park (Croxall, 1969; Smythies, 1999).

Non-bird biodiversity: The area supports a steadily increasing population of Proboscis Monkey (Bornean endemic colubine). Initially confined to Bako National Park, protection has increased the population within the Park to levels beyond its carrying capacity, and the excess is spreading across the bay and into Santubong. Groups can now be easily seen up the mountain and in the mangroves fringing the bay. The waters within the bay and its immediate surroundings support at least three species of dolphin: Indo-pacific Hump-back Dolphin Sousa chinensis, Finless Porpoise Neophocaena phocaenoides (Beasley, 1998) and Irrawaddy Dolphin Orcaella brevirostris. Irrawaddy Dolphins are relatively common in the bay, perhaps the most important, viable population in Sarawak. They are also increasingly becoming habituated, and dolphin-watching activities are increasing. Further off-shore in clearer waters, Sousa, and possibly Trusiops truncatus also occur. Orcealla brevirostrisy DolphinsThe only record for Borneo of Pygmy Sperm Whale Kogia breviceps was that of a stranding at Buntal on 19 February 1958 (Harrisson & Jamuh, 1958). The type specimen of the Borneo White Dolphin Sotalia borneensis, was collected at Tanjung Sipang, on the eastern side of the Bako promontory (mouth of the Sarawak river) in 1901 (Lydekker, 1901), but has subsequently been included as a predominantly pink form of Sousa chinensis.The brackish waters of the mangrove delta support a healthy population of Estuarine Crocodile Crocodylus porosus, and larger individuals can be observed basking along exposed mudbanks. Crocodile watching activities have failed to take off due to persistent culling of the population by the state authorities, in response to un-substantiated incidents of "attacks".Twenty-three species of mammals have been recorded in Bako NP (Rothschild, 1971; Start, 1972; Churchill and Zborowski, 1987; Hazebroek and Abang Kashim bin Abang Morshidi, 2000; Salter and Aken, 1983; Francis et al., 1984). Plants of interest include the ant plant Myrmecodia tuberosa, Clerodendrum fistulosum, Johannesteijsmannia altifrons, six species of Nepenthes spp., Drosera spathulata, Pholidocarpus maiadum and Cycas rumphii (Hazebroek and Abang Kashim bin Abang Morshidi, 2000).Globally threatened mammals (IUCN, 2002): Proboscis Monkey, Silvered Leaf-Monkey, Irrawaddy Dolphin, Indo-Pacific Hump-backed Dolphin, Bottlenose Dolphin ENDANGERED: Proboscis Monkey Nasalis larvatus; VULNERABLE: Cox's Roundleaf Bat Hipposideros coxi; NEAR THREATENED: Long-tailed Macaque Macaca fascicularis; DATA DEFICIENT: Hairy-nosed Otter Lutra sumatrana(II) Globally threatened reptiles (IUCN, 2002):(III) Globally threatened plants (IUCN, 2002): CRITICAL: Shorea longiflora, S. slootenii, S. elliptica, Dipterocarpus costulatus; ENDANGERED: Dryobalanops beccarii, Shorea bracteolata, S. pauciflora, S. ovata, S. stenoptera, Cotylelobium burckii; VULNERABLE: Sarawakodendron filamentosum, Nageia maxima, Microtropis rigida, Shorea macrophylla, Combretocarpus rotundatus; LOWER RISK/conservation dependent: Nepenthes albomarginata

Habitat and land use
Santubong: Four major vegetation types occur:Mixed dipterocarp forest. The predominant vegetation cover on the lower and middle slopes of the mountain, extending to the rocky coastline.Tropical heath forest. Occurs on the eastern side of the mountain where the terrain is level and gentley sloping. Lower stature than MDF, this habitat is part of the Riau pocket vegetation dating back to the Pleistocene, and is characteristic of western Borneo. Many endemic species within a unique floral assemblage.Beach vegetation: Characterised by species such as Dillenia, Callophyllum, Pandanus, Ixora, Hibiscus and Barringtonia. Occurs in narrow strips along the sea front.Summit vegetation: elements of sub-montane vegetation occurs on the summits. Subjected to dessicating effects of sea breezes and a rocky substrate, this low stature vegetation occurs on the peaks and highest ridge crests. Bako-Buntal Bay: Mangrove forest fringing the bay comprise Avicennia and Sonneratia interspersed with pockets of Rhizophora. Its western and eastern boundaries are described under Santubong and Bako respectively.Bako NP: Seven types of vegetation has been identified namely mangrove, beach forest, riparian and freshwater swamp forest, lowland dipterocarp forest, kerangas forest, open shrubland and fire padang, which is one of the characteristic features of Bako (Good, 1988). Mangrove forest. Three types of mangrove in Bako are identified. The first is Sonneratia alba that can be found along the sheltered areas of the coast on saline sands and clays. The second type develops on the heavier clays near the river channels and consists of Rhizophora mucronata and Avicennia officinalis. Lastly, dense stands of Nipa fruticans and Heritiera globosa are found on land that is flooded at high tide.Beach forest. Vegetation such as Casuarina equisetifolia, Barringtonia asiatic, Calophyllum inophyllum and Hibiscus tiliaceus dominate the coastal areas of the national park. This mixed forest has been disturbed by human activity in the past and has regenerated as secondary scrub.Riparian and freshwater swamp forest. Vegetation such as Artocarpus spp., Salacca conferta, Pandanus, Shorea stenoptera and Dipterocarpus spp. are found in this habitat on alluvial soils.Lowland dipterocarp forest. Occurs in Bako on the steeper slopes, which have deeper podsolised soils. Trees from the Dipterocarp family dominate this mixed habitat such as Shorea spp., Dipterocarpus spp., Dryobalanops spp., Anisoptera spp., Hopea spp. and Vatica sp..Kerangas forest. This is the most widespread forest type in the national park. Casuarina sumatrana and Dacrydium elatum are common. Ant plants and epiphytes such as Nepenthes sp., Drosera sp. and Burmannia sp. can be found in this forest type.Open shrubland. This habitat has many plant genera that appear to have historic links with Australia. These plants include Tristania sp., Gymnostoma sp., Baeckia sp., Austrobuxus sp., Styphelia sp., Podocarpus sp., and Dacrydium sp..Fire padang. This habitat type is found in the north-west of the national park and is probably the result of burnt kerangas forest. Vegetation include Ploiarium alternifolium, Cratoxylon glaucum, Dacrydium elatum and Combretocarpus rotundatus.

Pressure/threats to key biodiversity
The proximity of the site to Kuching, the capital and largest town in Sarawak, is a double-edged sword. The high human presence in the bay applies a constant stress on the site. There are two villages, Kampung Buntal and Kampung Bako, at either end of the bay. The primary income is from fishing, with an increasing participation of locals in tourism activities. Kampung Bako is the only entry point to the National Park, and villagers gain significant income from ferrying visitors to and fro the Park. Kampung Buntal is a popular sea food destination, some 35km from Kuching. The restaurants line the sandbar which is also the high tide roost for shorebirds. Recent efforts by the MNS to raise awareness of the site through local media and public activities at the site has had the effect of attracting hunters. The roost was abandoned by 2003, most of the birds moving to the opposite side of the bay and into the aquaculture ponds. If hunting can be stopped, the roost will be used again.Dolphins are frequently caught in fishing nets, with a high mortality rate. Unless measures are initiated to make fishing dolphin-friendly, this important population will disappear. Likewise, efforts are urgently required to protect the crocodile population here, which may be one of the most important populations in the State.

Protected areas
Santubong: Currently under State land. There are no plans to afford any legislative protection to this area. More development is planned for the mountain.Bako-Buntal Bay: Not protected. The mangrove forest belong to the Sarawak Mangrove Forest Reserve.Bako: Gazetted as a National Park in 1957 under the National Parks and Nature (Amendment) Ordinance 1990. The protected area covers the whole northern part of the Muara Tebas Peninsula. All forms of habitat disturbance and wildlife hunting are prohibited. However, in some cases, local communities that depend on resources within the park are granted exclusive rights to harvest them (Good, 1988). The Bako National Park is an IUCN Category II protected area.

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Bako-Buntal Bay. Downloaded from on 10/06/2023.