Pasonanca watershed (9812)
Philippines, Asia
Site overview
KBA status: confirmed
Global KBA criteria: B2
Year of last assessment: 2006
National site name: Pasonanca watershed
Central coordinates: Latitude: 6.8833, Longitude: 122.0667
System: marine, terrestrial
Elevation (m): 200 to 1100
Area of KBA (km2): 336.55331
Protected area coverage (%): 35.93
KBA classification: Global
Legacy site: Yes
Site details
Site description: Pasonanca Watershed is only 7 km north of Zamboanga City at the tip of the Zamboanga Peninsula in southwestern Mindanao. It has the largest block of old growth lowland dipterocarp forest remaining in Region 9, and a DENR Protected Area Survey Assessment (PASA) reports that old growth and secondary growth forest covers about 60% of the area. The rest is agricultural land, coconut plantations and built-up areas. Rock formations and numerous rivers and springs provide additional habitats for wildlife. It has a rolling terrain with moderate to steep slopes. Tenured migrants have occupied part of the watershed since the 1950s. Since it is close to the city, housing projects have been constructed by developers at the edge of the watershed. There is also a picnic and camping area adjacent to the watershed, including a Boy Scouts of the Philippines camp. Pasonanca Watershed is the only source of potable water for Zamboanga City, and the Tumaga River also provides industrial and irrigation water for the area around the city.
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: Many of the threatened and restricted-range species of the Mindanao and Eastern Visayas Endemic Bird Area have been recorded in or near to Pasonanca Watershed, including recent records of the threatened Mindanao Bleeding-heart, Philippine Kingfisher, Philippine Leafbird and Little Slaty Flycatcher, and Zamboanga Bulbul, which is confined to western Mindanao and Basilan. It is likely that the good quality habitat there supports some important populations of these birds.
Habitats
Summary of habitats in KBA: Pasonanca Watershed is only 7 km north of Zamboanga City at the tip of the Zamboanga Peninsula in southwestern Mindanao. It has the largest block of old growth lowland dipterocarp forest remaining in Region 9, and a DENR Protected Area Survey Assessment (PASA) reports that old growth and secondary growth forest covers about 60% of the area. The rest is agricultural land, coconut plantations and built-up areas. Rock formations and numerous rivers and springs provide additional habitats for wildlife. It has a rolling terrain with moderate to steep slopes. Tenured migrants have occupied part of the watershed since the 1950s. Since it is close to the city, housing projects have been constructed by developers at the edge of the watershed. There is also a picnic and camping area adjacent to the watershed, including a Boy Scouts of the Philippines camp. Pasonanca Watershed is the only source of potable water for Zamboanga City, and the Tumaga River also provides industrial and irrigation water for the area around the city.
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Forest | 67 | |
| Artificial - Terrestrial | 33 |
Threats
Summary of threats to biodiversity at KBA: The major pressure on this IBA is from an influx of migrants and illegal settlers into the watershed, who have engaged in kaingin, land conversion for agriculture and the illegal collection of timber. This is occurring mainly along the eastern and southern perimeters of the watershed, where it is believed that the forests are particularly vulnerable because there is no buffer of brush or open-canopy forest between the old growth forest and occupied lands. To the north of Pasonanca Watershed are open canopy residual forests that fall within the Curuan Watershed. This area is subject to intensive illegal logging and the timber is processed by several mini-sawmills within the forest zone. On the eastern portion, the rough terrain and high elevations have been a deterrent to settlers. However, there already are several new clearings in this area. If protection is not increased in this section, heavier incursion into the Curuan Watershed is certain in the near future.
Additional information
References: Haribon Foundation (1998).