Mount Silay and Mount Mandalagan (Northern Negros) (9762)
Philippines, Asia

Site overview

KBA status: confirmed

Global KBA criteria: B2

Year of last assessment: 2006

National site name: Mount Silay and Mount Mandalagan (Northern Negros)

Central coordinates: Latitude: 10.6333, Longitude: 123.2167

System: terrestrial

Elevation (m): 400 to 1885

Area of KBA (km²): 689.30652

Protected area coverage (%): 93.56

KBA classification: Global

Legacy site: Yes

Site details

Site description: North Negros Forest Reserve (NNFR) lies to the north of Mount Canlaon (PH063). It is an old forest reserve, mostly logged except for the two mountains, Mts. Silay and Mandalagan. These have extensive old growth forests on the higher slopes, and are connected by secondary forest. The area of NNFR is 80,454 ha, but only 16,687 ha of forest remains, of which c.75% is old growth and c.25% is secondary. The old growth is mainly above 1,000 m, but is found locally on very precipitous slopes at down to 700 m, and secondary forest is found at down to 400 m. The IBA is defined using the boundary of the remaining forest block, rather than the boundary of NNFR, as much non-forest land is included in that reserve. Much of the forest in this IBA is montane, including mossy forest at the highest altitudes, most of which is primary. There are some areas of primary lowland dipterocarp forest on the lower slopes, and extensive areas of secondary lowland forest. The forest on slopes of Mt Mandalagan is heterogeneous owing to the many steep-sided gorges and ridges in the area, and is very broken. Extensive areas on the steep slopes are, however, not forest, but rather covered by grasses, tree-ferns and scrub. This area is currently the largest tract of old growth forest left on Negros, which has only 4% of its original forest remaining. The secondary forest at 400 m is probably the only ‘true’ lowland forest remaining on Negros (although some forest survives at similar altitude in the Dumaguete City watershed area on Mt Talinis in PH066). This IBA forms the watershed of six major rivers in northern Negros that is the water source of 11 municipalities and cities and irrigates the islands' main rice production areas.

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. KBA identified in the CI/CEPF Conservation Outcomes booklet for the Philippines Hotspot (2006). Taxonomy, nomenclature and threat category follow the 2004 IUCN Red List.

Additional biodiversity: There have been several recent studies of the birds of Mt Silay and Mt Mandalagan (notably those of PESCP, the full details of which will be published shortly by Curio et al.), and many of the threatened and restricted-range species of the Negros and Panay Endemic Bird Area have been recorded there or reported by local people. This IBA includes the largest remaining areas of lowland forest on Negros, as well as extensive montane forests, and it is likely to prove to be very important for a number of threatened species, such as Negros-bleeding-heart, Visayan and Writhed-billed Hornbills and Visayan Flowerpecker. Non-bird biodiversity: The NNFR harbours both endemic plants and animals. For plants these include hardwood tree species (Dipterocarps), palms, orchids, herbs and trees with medicinal value. Animals include Philippine Spotted Deer Cervus alfredi, Visayan Warty Pig Sus cebifrons and butterflies. A giant fruit bat, the critically endangered Negros Naked-backed Fruit Bat Dobsonia chapmani may already be extinct. Several additional endangered mammal species may be present, but no surveys have been conducted yet.

Habitats

Summary of habitats in KBA: North Negros Forest Reserve (NNFR) lies to the north of Mount Canlaon (PH063). It is an old forest reserve, mostly logged except for the two mountains, Mts. Silay and Mandalagan. These have extensive old growth forests on the higher slopes, and are connected by secondary forest. The area of NNFR is 80,454 ha, but only 16,687 ha of forest remains, of which c.75% is old growth and c.25% is secondary. The old growth is mainly above 1,000 m, but is found locally on very precipitous slopes at down to 700 m, and secondary forest is found at down to 400 m. The IBA is defined using the boundary of the remaining forest block, rather than the boundary of NNFR, as much non-forest land is included in that reserve. Much of the forest in this IBA is montane, including mossy forest at the highest altitudes, most of which is primary. There are some areas of primary lowland dipterocarp forest on the lower slopes, and extensive areas of secondary lowland forest. The forest on slopes of Mt Mandalagan is heterogeneous owing to the many steep-sided gorges and ridges in the area, and is very broken. Extensive areas on the steep slopes are, however, not forest, but rather covered by grasses, tree-ferns and scrub. This area is currently the largest tract of old growth forest left on Negros, which has only 4% of its original forest remaining. The secondary forest at 400 m is probably the only ‘true’ lowland forest remaining on Negros (although some forest survives at similar altitude in the Dumaguete City watershed area on Mt Talinis in PH066). This IBA forms the watershed of six major rivers in northern Negros that is the water source of 11 municipalities and cities and irrigates the islands' main rice production areas.

IUCN Habitat	Coverage %	Habitat detail
Artificial - Terrestrial	33
Forest	67

Threats

Summary of threats to biodiversity at KBA: Owing to the rough topography and steepness of terrain, kaingin is encroaching into the montane forest here at a slower rate than elsewhere on Negros. However, many areas have been logged, and illegal commercial logging continues in the good quality residual timber stands. Two well-worn trails into the area are used to transport rattan and timber. The denudation of the lower slopes of Mts. Silay and Mandalagan has resulted in flash flooding during heavy typhoons. The most recent flooding in 1995 rendered hundreds homeless, destroyed agricultural land, sugar farms, rice plantations and fishpond holdings, and caused losses estimated at 60 million pesos. Due to excessive hunting in the NNFR, larger birds are scarce, including hornbills and fruit pigeons.

Additional information