Mount Siburan (9742)
Philippines, Asia
Site overview
KBA status: confirmed
Global KBA criteria: B2
Year of last assessment: 2010
National site name: Mount Siburan
Central coordinates: Latitude: 12.8000, Longitude: 120.9167
System: freshwater, terrestrial
Elevation (m): 50 to 400
Area of KBA (km2): 115.64006
Protected area coverage (%): 63.06
KBA classification: Global
Legacy site: Yes
Site details
Site description: Siburan is the largest tract of lowland forest known on Mindoro. It is adjacent to the large Sablayan penal colony, which restricts access to the forest and therefore provides some degree of protection. The forest is about 30 km south-east of Sablayan, with forest on the south and east edge of the penal colony. This forest is contiguous with the patchy forests on the limestone ridge running north from Malpalon (PH043). In 1991, it was estimated that about 1,500 ha of lowland forest remains, with a similar area of unvisited montane forest further east. The lowland forest is generally closed canopy with trees of up to 25 m or more and a relatively open forest floor. There are fewer limestone outcrops causing less disruption to the canopy than at Malpalon. The small Lake Lubao borders the forest.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for at least one criterion described in the Global Standard for the Identification of KBAs.
Additional biodiversity: Most of the threatened and restricted-range lowland forest birds of the Mindoro Endemic Bird Area have been recorded recently at Siburan. It is almost certainly the largest and most important lowland forest site on Mindoro, particularly given the current relatively low level of disturbance there. The protection of this IBA probably represents the best opportunity to prevent the extinction of the highly threatened Mindoro Bleeding-heart, Black-hooded Coucal and Mindoro Hornbill. Lake Lubao, bordering the forest, holds a few waterbirds. Non-bird biodiversity: This IBA is likely to support endemic small mammals, etc., but surveys of the mammalian fauna and herpetofauna are yet to be conducted there.
Habitats
Summary of habitats in KBA: Siburan is the largest tract of lowland forest known on Mindoro. It is adjacent to the large Sablayan penal colony, which restricts access to the forest and therefore provides some degree of protection. The forest is about 30 km south-east of Sablayan, with forest on the south and east edge of the penal colony. This forest is contiguous with the patchy forests on the limestone ridge running north from Malpalon (PH043). In 1991, it was estimated that about 1,500 ha of lowland forest remains, with a similar area of unvisited montane forest further east. The lowland forest is generally closed canopy with trees of up to 25 m or more and a relatively open forest floor. There are fewer limestone outcrops causing less disruption to the canopy than at Malpalon. The small Lake Lubao borders the forest.
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Forest | 50 | |
| Wetlands(Inland) | 25 | |
| Artificial - Terrestrial | 25 |
Threats
Summary of threats to biodiversity at KBA: The future of Siburan is not secure, although there is presumably some degree of protection afforded by the proximity of the penal colony. The prisoners have some impact on the forest, as they use it for the collection of firewood, rattan and bamboo, and for snaring birds. Species such as Black-hooded Coucal may be confined to undisturbed areas of forest where dense tangles of vines and rattans are found, and this is being slowly cleared away from the forest nearest to the prison, due to the collection of rattan for furniture production by the prisoners. A large tree felled at this location was being milled on site for either furniture or building purposes. However, in general there are minimal signs of human activity in the forest, with very few paths and no logging reported. A serious threat is posed to Siburan by encroaching slash-and-burn cultivation (kaingin), both by local people and the refugees. The influence of the penal colony has so far kept such deforestation to a minimum, but the forest has no formal protection and is likely to come under increasing pressure in the future.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Agriculture & aquaculture | Annual & perennial non-timber crops | Shifting agriculture | Ongoing |
| Natural system modifications | Dams & water management/use | Abstraction of surface water (agricultural use) | Ongoing |
| Biological resource use | Hunting & collecting terrestrial animals | Unintentional effects (species being assessed is not the target) | Ongoing |
| Human intrusions & disturbance | Work & other activities | Ongoing |
Additional information
References: Brooks et al. (1995b); Dutson et al. (1992); Evans et al. (1993a).