Bako-Buntal Bay

Country/territory: Malaysia

IBA Criteria met: A1, A3, A4i (2004)
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Area: 3,590 ha

Protection status:

Malaysian Nature Society

Site description
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

Recommended citation
BirdLife International (2018) Important Bird Areas factsheet: Bako-Buntal Bay. Downloaded from on 19/01/2018.