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Site description (2003 baseline):
Site location and context
(I) Physical CharacteristicsThe Kabili-Sepilok Forest Reserve (commonly known as Sepilok) derived its name from two rivers draining into Sandakan Bay. The area is mostly flat, alluvial and slightly undulating. Sandstone ridges are a dominant feature of the forest reserve. There are no large rivers in the area. Drainage to the south, into the Sandakan Bay, is by the Sungai Kabili, Sungai Pakis, Sungai Pandan, Sungai Cina, Sungai Sepilok Kecil, Sungai Sepilok Besar and Sungai Arang. The upper tributaries of the Kabili and Sepilok Besar have their sources within privately-owned, cultivated land, while the other rivers have their entire catchments within the reserve. Drainage from from the north side of the reserve is into Sungai Gum Gum Besar. On the eastern side, drainage is into Sungai Seguntong via Sungai Matalau and several small streams including Masbud, Buaya, Simpang Dua and Simpang Tiga (Payne, 1988).Most of the reserve has classified as the Sandakan Formation consisting mainly of sanstones and mudstones which has been estimated to be upper Miocene or younger in age. Fine to medium-grained sandstone, pale yellow, orange or greyish in colour, predominates in the higher, dissected ridges, while brown or grey mudstones predominate in the intervening lower land of more moderate terrain (Payne, 1988). Four soil associations are recognised within the reserve. Red-yellow podzols occur on the sandstone ridge crests while the sandy lithosols occur on the steep slopes. Extensive podzols are developed on the west. Soils on low mudstone and sandstone hills and alluvial flats occur elsewhere, away from the coastal swamps. Coastal swamp soils are periodically inundated with saline water (Payne, 1988). (II) Climatic ConditionsHeavy rains from the north-east in December and January, rainfall largely influenced by the north-east winds, which generally falls between November and mid-February. The total annual rainfall is about 3,000 mm. Mean daily temperature is 30
oC (DWNP, 1987).
Over 200 species of birds have been recorded in the area including several globally endangered species (Payne, 1988). The Kabili-Sepilok Forest Reserve is broadly typical of the lowlands of eastern Sabah. The area is also important for biome and extreme lowland species. The Near Threatened Oriental Darter
Anhinga melanogaster has been recorded in the forest reserves (Sheldon
et al., 2001).
Non-bird biodiversity: Over 90 species of mammals have been recorded in Sepilok Forest Reserve (Payne, 1988, Matsubayashi et al., 2003). The Asian Elephant Elephas maximus, Sumatran Rhinoceros Dicerorhinus sumatrensis and Tembadau (Bos javanicus) are absent in the reserve but old records showed that they were once found in the area. There is little information on the reptiles, amphibians and freshwater fishes of Sepilok. At least two species of freshwater fishes known only from small streams in eastern Sabah, Acanthophthalmus sandakanensis and Mastacembelus keithi occur within the reserve. Turtles have been spotted in the mangrove channels during surveys. Insect diversity includes 70 species of butterflies (Fox, 1973).(I) Globally threatened mammals (IUCN, 2002): ENDANGERED: Orang-Utan Pongo pygmaeus; VULNERABLE: Ridley's Roundleaf Bat Hipposideros ridleyi, Clouded Leopard Neofelis nebulosa, Ranee Mouse Haeromys margarettae; NEAR THREATENED: Dayak Fruit Bat Dyacopterus spadiceus, Small Woolly Bat Kerivoula intermedia, Bronzed Tube-nosed Bat Murina aenea, Large Brown Myotis Myotis montivagus, Ridley's Myotis Myotis ridleyi, Ridley's Roundleaf Bat Hipposideros ridleyi, [Hairy-winged Bat Harpiocephalus mordax]; DATA DEFICIENT: Malayan Sun Bear Helarctos malayanus (II) Globally threatened reptiles (IUCN, 2002): No information.(III) Globally threatened plants (IUCN, 2002): ENDANGERED: Dryobalanops lanceolata; VULNERABLE: Eusideroxylon zwageriNote: [ ] = unconfirmed record.
Three forest types have been recognised within the reserve namely lowland dipterocarp forest, sandstone hill dipterocarp forest,
kerangas forest and mangroves (Fox, 1973 cited in Payne, 1988).The lowland dipterocarp forest is dominated by
Parashorea tomentella, Shorea leptoclados and
Dryobalanops lanceolata.
Eusideroxylon zwageri, Diospyros spp. and
Hydnocarpus spp. are common in the middle canopy.Dipterocarps such as
Shorea beccariana, S. multiflora and
Dipterocarpus acutangulus are common in the sandstone hill dipterocarp forest, which occur extensively on the sandstone ridges in both the western and eastern parts of the reserve.In the kerangas forest, dipterocarps are scarce except for
S. multiflora. The forest canopy is low and even, with
Tristania clementis and
Ixonanthes reticulata as dominant species. This forest type occurs on the sandstone cuestas in the eastern half of the reserve.Mangrove forest occurs to the south of the reserve.
Oncosperma tigillarium occurs in the transitional zone between the lowland dipterocarp forest and mangrove, which on the inland side is dominated by
Bruguiera gymnorrhiza. Along the mangrove channels are
Rhizophora apiculata, Ceriops tagal, Xylocarpus granatum and
Lumnitzera littorea, while
R. mucronata lines Sandakan Bay.
Pressure/threats to key biodiversity
Some illegal logging occurred in 1967 within the reserve. Illegal poaching is minimal.
An area of 2,335 ha was gazetted as Kabili-Sepilok Forest Reserve in 1931 (Gazette Notification No 80/1931) encompassing much of the drainage of the Sungai Kabili, Sepilok Kecil and Sepilok Besar, and constituting what is now the western portion of the reserve. Another 1,874 ha of what is now the eastern portion was added in 1938 (G.N. No 322/1938). Additions in the north and south-east added 264 ha. Subsequent excisions from the south-eastern side (GN No 617/1965) and an extension on the northern side leave a total area of 4,294 ha. This area was formally gazetted as Class VI Virgin Jungle Reserve (VJR) in the Forest (Amendments) Enactment 1984 (No. 4/1984) and Section 15 of the Forest Enactment 1968 (No 2/1968) specifically prohibits the removal of forest produce from the reserves. Since 1957, logging was banned from the reserve (Payne 1988).The mangrove forests fringing the south side of Sepilok Forest Reserve are protected as Sepilok Mangrove Virgin Jungle reserve (1,235 ha; not part of Kabili-Sepilok Virgin Jungle Reserve) and they are contiguous with Elopura Mangrove Forest Reserve (2,4674 ha), which extends around Sandakan Bay and includes mangrove areas of some of the islands (Payne, 1988). The VJR is also gazetted under the Cultural Heritage Conservation Enactment 1997 (Regis, 2001) and classified under the IUCN Category Ia protected area.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Kabili-Sepilok (Malaysia). Downloaded from
https://datazone.birdlife.org/site/factsheet/kabili-sepilok-iba-malaysia on 23/12/2024.
