PH019
Angat watershed


Year of compilation: 2001

Site description
Most of the remaining closed-canopy forests in Region III are found in Bulacan Province, principally in the Angat Dam Watershed which lies about 35 km to the north of Metro Manila. The watershed supports lowland dipterocarp stands on moderate to very rough terrain between elevations of 490 to 920 m, although much of the accessible forest is now degraded, and there are many areas of secondary bamboo. The forests here are of relatively low stature, and grow on what appear to be poor soils with no humus layer. The areas surrounding the forest are covered in sparse scrub and grassland. The forests here are essential for the water and the electricity supply of Manila, much of which is generated by the Angat Hydroelectric Dam.

Key biodiversity
The forests around Angat Dam are a popular destination for bird-watchers, and there are recent records of many of the threatened and restricted-range birds of the Luzon Endemic Bird Area. This is one of the few places where there are recent records of large flocks of Spotted Imperial-pigeon. Some of these species have also been recorded just outside the IBA at Ipo Dam, and the record of the extremely poorly known Worcester's Buttonquail there is of particular interest.

Non-bird biodiversity: Mammals recorded in the area include two globally near-threatened species, Crab-Eating Macaque Macaca fascicularis and Philippine Warty Pig Sus philippensis, and the Data Deficient Philippine Brown Deer Cervus mariannus.



Pressure/threats to key biodiversity
Despite the importance of this watershed for the water and the electricity supply of Manila, there are communities living within the watershed and there is serious forest degradation in the vicinity of the dam. Many of the largest trees are being removed, and rattan is collected. It is estimated that the area of closed canopy forest in Bulacan Province was reduced by 47% between 1981 and 1992. Large scale trapping of Colasisi Loriculus philippensis for the bird trade has recently been observed in this IBA, and pigeons and malkohas are trapped for food.

Protected areas
Angat Watershed and Forest Range (6,600 ha) was proclaimed a Watershed Forest Reserve by Proclamation No. 391 on 30 April 1968, and is proposed as a protected landscape under NIPAS. The much larger Angat Watershed Metro Water District (55,707 ha) overlaps with the IBA, and was established by virtue of Proclamation No. 71 on 10 February 1927, and is also proposed as a protected landscape under NIPAS.

Habitat and land use
Most of the remaining closed-canopy forests in Region III are found in Bulacan Province, principally in the Angat Dam Watershed which lies about 35 km to the north of Metro Manila. The watershed supports lowland dipterocarp stands on moderate to very rough terrain between elevations of 490 to 920 m, although much of the accessible forest is now degraded, and there are many areas of secondary bamboo. The forests here are of relatively low stature, and grow on what appear to be poor soils with no humus layer. The areas surrounding the forest are covered in sparse scrub and grassland. The forests here are essential for the water and the electricity supply of Manila, much of which is generated by the Angat Hydroelectric Dam.


Recommended citation
BirdLife International (2022) Important Bird Areas factsheet: Angat watershed. Downloaded from http://www.birdlife.org on 25/06/2022.