Kinabatangan floodplain

Site description (2003 baseline):

Site location and context
(I) Physical CharacteristicsThe proposed Kinabatangan Wildlife Sanctuary is essentially an important floodplain in Sabah and also the largest. The area comprises tracts of land that link the mangrove areas near the coast with the existing protected areas further inland, creating a corridor of floodplain habitat to maintain the ranging patterns of native wildlife (Prudente and Balamurugan, 1999). Several natural habitat types are found here such as limestone outcrops, oxbow lakes, riverine forest vegetation, dry lowland dipterocarp forest, seasonal swamps and tidal mangroves (WWFM, 1998, n.d.).Sungai Kinabatangan, Sabah's largest and longest river (560 km), runs through the floodplains, which is subjected to seasonal flooding. The river has a catchment area of about 1,680,000 ha, covering almost 23% of the total land area in Sabah. The southern branch of the river originates in the Kuamut Highlands while the northern branch originates from Banjaran Trus Madi and Labuk Highlands. The river flows eastwards before discharging into the Sulu Sea. The main tributaries of the Kinabatangan are Kuamut, Milian, Sapasidom, Menanggul, Tenegang Besar, Koyah, Maliau, Pinangoh and Lokan (Prudente and Balamurugan, 1999). (II) Climatic ConditionsMean annual rainfall is approximately 2,600 mm, well distributed with slightly more in December and January. Lowest rainfall occurs in March-April. Mean diurnal temperature average between 32-22oC (DWNP, 1987).

Key biodiversity
The Kinabatangan wetlands is an important site for several globally threatened waterbirds especially Storm's Stork Ciconia stormi, where the last viable population in the country remains. One hundred and eighty-nine bird species have been recorded and some breeding (Sharma, 1992). The Near Threatened Oriental Darter Anhinga melanogaster is found to be common and breeding in the area (Sharma, 1992; Smythies, 1999; Sheldon et al., 2001). Others include the wetland raptors Grey-headed Ichthyophaga ichthyaetus and Lesser Fish-eagle I. humilis (Sharma, 1992). Locally, the Gomantong Caves is one of Sabah's two most important sites for birds' nest trade (WWFM, n.d.).

Non-bird biodiversity: About 50 species of mammals are recorded including a small population of the Asian Elephant Elephas maximus and possibly the Sumatran Rhinoceros Dicerorhinus sumatrensis (WWF, 2002a; Payne and Francis, 1985). The Kinabatangan contains the largest Malaysian population of Proboscis Monkey Nasalis larvatus (Buckley, 2002; Bennett and Gombek, 1993; Prudente and Balamurugan, 1999). Twenty-seven species of reptiles and amphibians were recorded (Sharma, 1992; Whittaker, 1984). Freshwater fish diversity and productivity is very high. More than 100 species have been recorded so far. The Irrawaddy Dolphin Orcaella brevirostris have been reported 20 km up Sungai Kinabatangan (Dolar et al., 1997 in Smith and Jefferson, 2002). Recently, the Borneo River Shark Glyphis sp. known from a few immature specimens, not yet named and thought to be extinct, was rediscovered in the lower Sungai Kinabatangan. This species was listed as Critically Endangered in the 1996 IUCN Red List of Threatened Animals (Prudente and Balamurugan, 1999). Plants of special interest in this region include Koompassia excelsa, Terminalia copelandi, Ficus racemosa and Mitragyna speciosa (Boonratana, 2000; Reza Azmi, 1998; Sharma, 1992).(I)Globally threatened mammals (IUCN, 2002): CRITICAL: Sumatran Rhinoceros Dicerorhinus sumatrensis; ENDANGERED: Asian Elephant Elephas maximus, Proboscis Monkey Nasalis larvatus, Tembadau Bos javanicus, Orang-Utan Pongo pygmaeus; VULNERABLE: Pig-tailed Macaque Macaca nemestrina, Common Porcupine Hystrix brachyura, Smooth Otter Lutrogale perspicillata, Clouded Leopard Neofelis nebulosa, Flat-headed Cat Prionailurus planiceps, Bare-backed Rousette Rousettus spinalatus; NEAR THREATENED: Long-tailed Macaque M. fascicularis, Bornean Gibbon Hylobates muelleri, Pangolin Manis javanica, Oriental Small-clawed Otter Amblonyx cinereus, Gilded Tube-nosed Bat Murina rozendaali, Philippine Horseshoe Bat Rhinolophus philippinensis; DATA DEFICIENT: Hairy-nosed Otter Lutra sumatrana, Irrawaddy Dolphin Orcaella brevirostris, Hose's Langur Presbytis hosei, Malayan Sun Bear Helarctos malayanus(II) Globally threatened reptiles (IUCN, 2002): (III) Globally threatened plants (IUCN, 2002):

Habitat and land use
The principal vegetation throughout the area is riverine forest, freshwater swamp forest, peat swamp forest and open reed swamps. Large number of meanders and ox bow lakes (about twenty) occur in the region due to the active process of erosion and deposition. Besides ox bow lakes, there are also several shallow freshwater lakes along the river notably Butong and Labaung near Bukit Garam. The seaward end of the Kinabatangan region consists of extensive mangrove forests and nipa palm stands. Limestone forest can be seen at Sukau and near Batu Putih. The surrounding areas consist of remnants of pristine lowland dipterocarp forest and logged-over swamp forest, burnt lowland dipterocarp forest, cocoa and oil palm plantation wildlife (Boonratana, 2000; Sharma, 1992; Prudente and Balamurugan, 1999). 1,500 plant species occur in lowland dipterocarp forest, 600 in freshwater and riverine forests, 300 on limestone outcrops, 50 in mangroves and coastal forest, and 10 in lakes and treeless wetlands (WWFM, n.d.).Details of the vegetation type is described below (Reza Azmi, 1998):The riverine forest is comprised of mixed dipterocarp species tolerant of high water tables and periodic flooding by the rise of the muddy-waters of the rivers. The forests are best developed on storm-deposited levees of Sungai Kinabatangan and its tributaries, above the tidal influence and up to the middle reaches of the river course. Dipterocarp species included Shorea leprosula, S. johorensis, S. macrophylla, S. mecistopteryx, S. seminis, S. splendida, Dipterocarpus applanatus, D. validus, D. oblongifolius, Parashorea malaanonan and sometimes on the fringes of riverine forests, P. tomentella. Other common associates included Intsia palembanica, Eusideroxylon zwagerii, Pometia pinnata and Dracontomelon dao. Understorey vegetation include Syzygium, Diospyros, Nauclea orientalis, Baccaurea tetrandra, Pholidocarpus maiadum, Salacca and Licuala.The forest of peat swamps occurs north of the Kinabatangan, between Batu Putih and Sukau. It generally ranges between 12-21 m high, but with irregular tree cover and sometimes an altogether open swamp vegetation. The undergrowth is dense with sedges and ferns, and trees are almost choked by the climber Stenochlaena palustris. Common trees in Ilex cymosa, Buchanania arborescens, Ficus sundaica, Santiria oblongifoila, Syzygium sarawacense, Notaphoebe kingiana and Diospyros elliptifolia.Permanent freshwater swamp forest occurs on the Kinabatangan floodplain and its tributaries, and also sporadically in poorly-drained minor valleys. Depending on the degree of inundation, the vegetation may vary between open, herbaceous swamps and tall swamp forest. The trees of swamp forest include Elaeocarpus sp., Lophopetalum multinervum, Dillenia borneensis, Dracontomelon dao and Mallotus muticus, which have special adaptations to water-logged or unstable soils. The undergrowth may be sparse or dense with small bushes, grasses and sedges; sometimes almost pure stands of Thorostachyum may entirely dominate the understorey. Mixed tree association can also be observed in the forest, which is dominated by Pternandra galeata, Vitex, Dialium, Alstonia, Campnosperma, Syzygium, Canarium and Callophyllum.Floating meadows of carpets of grasses, sedges and broad-leaved floating plants are common along the edge of riverbanks, sluggish streams, stagnant water or shallower, wind-protected parts of ox bow lakes. The mangroves are located at the seaward end of the Kinabatangan delta while at the inland edge of the delta, tidal creeks and estuaries, brackish-water forest develops which consists of pure stands of nipa palms, Nypa frutescens. Common mangrove associates include Avicennia spp., Sonneratia caseolaris, Rhizophora spp., Brugueira spp., Lumnitzera spp., Xylocarpus spp. and Ceriops tagal.Limestone forest and cliff vegetation can be found on the limestone outcrops. The forest often resembles the lowland mixed dipterocarp forest. Shrubs are sparse, shade epiphytes rare and woody climbers present but not abundant. Cliff vegetation consists of fairly open forests that are formed on steep, boulder-strewn scree slopes. They are composed of few widely spaced trees, and large emergent trees such as Azadirachta excelsa, Scorodocarpus borneensis and Sindora coriacea. In areas where screes of eroded rocks and damp calcium-rich soils are found, a rich shrub-herb flora develops.

Pressure/threats to key biodiversity
The Kinabatangan area has been identified as having ecotourism potential in the National Ecotourism Plan (MOCAT, 1997) and the Sabah Tourism Masterplan as a Nature Tourism Destination (Partners for Wetlands, 2001). Currently, all tourism activities are centred at Sukau, causing congestion and disturbances to the local wildlife. Efforts are being made to address the situation by developing additional two locations, Abai and Bilit, for tourism (WWFM, n.d.). Development of tourism within the area will continue and the need to strike a balance between conservation (species, habitat and culture) and tourism will be crucial. Logging and land clearing for oil palm plantation are the main threats to the Kinabatangan region (DWNP, 1987; Partners for Wetlands, 2000; Prudente and Balamurugan, 1999). These activities, coupled with the rapid change in land use, have resulted in several serious ecological problems to the habitats and wildlife, which are described below;Declining water quality in the Kinabatangan and its tributaries have been recorded since 1960s when commercial logging started in the upper catchment and worsened in the 1980s when oil palm plantations and mills started operations. The main pollution sources in the Sungai Kinabatangan catchment currently are effluent from palm oil mills, pesticides, fertilizers and sediment from plantations, sediment from logging activities and sewage and refuse from villages along the river. Flooding caused by removal of forest cover and the expansion of plantations as the current practices of land clearing lead to substantial soil compaction. Flooding in the region will increase with the expansion of plantations and logging activities. Large mammals such as the Asian Elephants and their young will suffer during such period as they have no dry land to rest and resort to invade plantations.Hunting, mainly illegal, is still rampant within the Bukit Garam area, where most of the remaining forested areas are on SAFODA land, forest reserves and within the proposed wildlife sanctuary. As a result of this, declines in wildlife populations have occurred. Targeted species include the Sambar Deer, Mousedeer, wild cattle, waterhens, pigeons, egrets, Estuarine Crocodile, Hill Myna, hanging-parrot, White-rumped Shama, Pig-tailed and Long-tailed Macaque.Fragmentation of the forest may lead to the extinction of several species of flora and fauna. The possible decline of the Proboscis Monkey populations is linked to the disappearance of its preferred habitats (Buckley, 2002).{conflicts especially with the Asian Elephants (Partners for Wetlands, 2002).

Protected areas
Historically, much of the Kinabatangan region's forest has been logged in the past. After a comprehensive survey in 1991, WWFM proposed the establishment of the Lower Kinabatangan Wildlife Sanctuary. The proposal was subsequently endorsed by the Sabah State Government.Currently, WWFM has embarked on the "Partners for Wetlands" project, a major conservation work along the Lower Sungai Kinabatangan, under a Memorandum of Understanding with the Sabah Wildlife Department. The project aims at establishing partnerships that benefit major landowners and local communities as well as wildlife and the environment and developing a long-term sustainable land use in the Kinabatangan catchment that benefits all parties, including for agriculture and forestry, currently operating in the lower Kinabatangan (Jaswinder Kaur, 2002; Prudente and Balamurugan, 1999; Prudente et al., 2002).In November 1999, the Lower Kinabatangan was announced as Malaysia's Gift to The Earth by the Chief Minister of Sabah and as a commitment to fully gazette and protect the 27,000 ha of wetlands as a wildlife sanctuary (Partners for Wetlands, 2001) under the Land Ordinance 1960 (amended 1967), Sabah Cap 68 and Wildlife Conservation Enactment 1997 (Anon., 2002).

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Kinabatangan floodplain. Downloaded from on 08/12/2023.