(I) Physical CharacteristicsDanum Valley Conservation Area is located in eastern Sabah, near Lahad Datu. The protected area occupies much of the upper catchment of Sungai Segama and comprises mostly rugged terrain at between 150-1,000 m asl. It is also the best representation of a continuous transition of undisturbed lowland dipterocarp forest to highland forest in Sabah. Three major summits can be found within the area; Gunung Nicola (917 m asl) on the northern perimeter, Gunung Danum (1,093 m asl) in the centre and Gunung Tribulation (861 m asl) in the upper Segama highland to the south-west.Three main types of geological formation have been identified in the area; the Crystalline Basement, Chert-spellite and the Kuamut (Marsh and Greer, 1992 cited in Magintan, 2000). The Chert-spillite formations occur to the north of Sungai Segama. It is composed of metamorphic and ultrabasic rocks of the Upper Cretaceous to early Tertiary age. Most of the soils is represented by two associations; the Mentapok Association and the Bang Association. The Mentapok Association corresponds to the hilly-mountain landform of Danum Valley. These soils are derived mainly from basic and intermediate igneous rocks and consist of chromic and orthic luvisols, euthric cambisols nad lithosols (Wright 1975, cited in Magintan, 2000). The Bang Association developed over rocks of the Kuamut Formation.(II) Climatic ConditionsThe area experiences two monsoon seasons with a wetter period affected by the north-east monsoon (December-March) and a drier period by the south-east monsoon (May-October), with rainfall ranging from 2,000 mm to 3,300 mm. Temperatures range from 22.5oC to 30.9oC with annual high humidity (Norhayati et al., 2001).
The primary lowland dipterocarp forest in Danum Valley supports several important globally threatened species and a rich diversity of biome-related species. Over 275 species have been recorded (Kiew, 1976; Marsh 1995; Mohamed Zakaria bin Hussin 1992; Showler, 1992; WWFM, 1998; MacKinnon and Phillipps 1993; Sheldon et al., 2001). All hornbill species in Sabah are also present in the area. At least 9 endemics (Lambert 1993), three dependent on unlogged forest Black-throated Wren-babbler Napothera atrigularis, Bornean Wren-babbler Ptilocichla leucogrammica and Bornean Blue Flycatcher Cyornis superbus. Other Near Threatened species recorded are the Oriental Darter Anhinga melanogaster and Lesser Fish-eagle Ichthyophaga humilis (Kiew, 1976; Sheldon et al., 2001).
Non-bird biodiversity: One hundred and twenty species of mammals, 72 reptiles, 56 amphibians and 37 fishes have been identified (Kiew, 1976; Showler, 1992; Heydon and Bulloh, 1996; (Payne and Francis, 1985). Significant populations of 10 species of primates, including the Orang-Utan Pongo pygmaeus and Proboscis Monkey Nasalis larvatus are present. A small number of Sumatran Rhinoceros Dicerorhinus sumatrensis (probably less than 20 individuals) may be present in the area, making this one of only two or three such sites known in Borneo, a crucial refuge for their continued survival (WWF, 2002a). (I)Globally threatened mammals (IUCN, 2002): CRITICAL: Sumatran Rhinoceros Dicerorhinus sumatrensis; ENDANGERED: Asian Elephant Elephas maximus, Orang-Utan Pongo pygmaeus; Proboscis Monkey Nasalis larvatus; Bay Cat Catopuma badia, Otter-Civet Cynogale bennettii; VULNERABLE: Pig-tailed Macaque Macaca nemestrina; NEAR THREATENED: Bornean Gibbon Hylobates muelleri, Long-tailed Macaque M. fascicularis; DATA DEFICIENT: Malayan Sun Bear Helarctos malayanus, Hairy-nosed Otter Lutra sumatrana, Hose's Langur Presbytis hosei(II) Globally threatened reptiles (IUCN, 2002): No information.(III) Globally threatened plants (IUCN, 2002): CRITICAL: Parashorea malaanonan, Shorea johorensis; ENDANGERED: Shorea pauciflora, Dryobalanops lanceolata; VULNERABLE: Engelhardia danumensis, Aglaia laxiflora, Mangifera rufocostata
Pressure/threats to key biodiversity
Concerns include logging and its ecological effects on the wildlife, forest fires (during drought periods), hunting pressure and forest produce gathering due to the accessibility through logging roads. Mining and hydro-power development may pose as a future threat as the Segama River has been known to be a source of pannable alluvial gold and potential energy source. Introduced species and forest fire are lesser threats (Johns, 1991; Marsh, 1995; Mohamed Zakaria bin Hussin, 1992; Heydon and Bulloh, 1996; Mohd. Nordin Hj. Hasan and Mohamed Zakaria Hussin, 1997; Norhayati et al., 2001). Currently, the conversion of the surrounding forests to plantations is occurring on the western side of the area and may be viewed as a very grave and real threat (Stuebing, pers. comm.).
The Danum Valley Conservation Area was formerly part of a 972,000 ha forest concession assigned to Yayasan Sabah (the Sabah Foundation) which was spared from logging in 1981 in recognition of its outstanding biodiversity. It was gazetted under the Forest Enactment 1968 as a Class I (Protection) Forest Reserve by the Sabah State Legislative Assembly, under the authority of the Sabah Forestry Department in May 1995. The inter-agency, Danum Valley Management Committee, is responsible for the management and administration of the area. The area was also gazetted under the Cultural Heritage Conservation Enactment 1997 (Regis, 2001).Currently, there is no legal protection for the buffer zones along the south and western boundaries of the site. Proposals have been made to re-gazette a buffer zone of 67,000 ha of logged forest as the Danum Valley Class VII (Wildlife) Forest Reserve. The conversion would protect against future re-logging or conversion to industrial tree plantations and create a 'Greater Danum Valley Conservation Area of about 110,000 ha (Marsh, 1995).
Habitat and land use
The primary lowland dipterocarp forest in the area is dominated by trees from the Dipterocarpaceae family. Parashorea malaanonan predominates over much of the upper Segama region. Parashorea malaanonan, P. tomentella, Shorea johorensis and Rubroshorea spp. dominate the upper canopy around Danum Valley. Large palms are rare in this forest. Trees from the genera Saraca, Eugenia, Pterospermum, Leea and Dillenia dominate the riverine and streamside scene. Along Sungai Segama, but rarely on smaller streams, Octomeles sumatrana forms scattered clumps. Away from the immediate riparian strip, and above the flood level is a zone about 200 m deep in which large trees are relatively scarce and the understorey contains a high density of vines. Vegetation at the higher elevation such as Gunung Danum is dominated by small-crowned trees, Dacrydium spp. and other gymnosperms like Phylocladus hypophylus, Podocarpus spp. and others ((Marsh, 1995; Adam and Omar, 2002).
BirdLife International (2020) Important Bird Areas factsheet: Danum Valley Conservation Area. Downloaded from
http://www.birdlife.org on 07/07/2020.