Distribution and Status of Peatlands in the Philippines
There are two areas in the Philippines where substantial areas of peat have been found: the Agusan Marsh and the Leyte Sab-a Basin. There has been a lack of targeted surveys for peatlands, but information indicates that there are almost certainly other areas. The location of these areas is shown in Figure 1.
The Sab-a Basin is a west-east elongated basin close to the north coast of Leyte separated from it by a metamorphic ridge. The total area is c. 3,088 ha of which 44% has been reclaimed for agriculture. The remaining unutilised peatland (1,740 ha) in the eastern half of the basin consists of small remnant areas of swamp forest and sedge/grass peat swamp (ADB 2000). The two smaller peat basins in the area Daguitan (210 ha) and Kapiwaran (430 ha) have mostly been converted to agricultural land.
The Agusan Marsh may hold the largest area of peatland in the Philippines. At present, there is no reliable estimate of the area and distribution of peat within Agusan Marsh. Two areas of peatland within the marsh have been confirmed – one just to the north of Bunawan, the vegetation of which has mostly been cleared and burned, and the other to the west of Caimpugan, which exhibits the characteristics of a peat dome, the forest of which is mostly intact except close to the Hibong River. There may be other areas of peat within the marsh, especially in Terminalia copelandii/ Metroxylon sagu forests in the northwest portion of the marsh.
Peat may also be present in the following areas:
- Ligawasan Marsh in Mindanao, the largest marshland area in the Philippines
- Dolongan area in Basey, Western Samar (Bureau of Soils, 1975. Soil Survey of Samar Provinces, Philippines. Reconnaissance Soil Survey and Soil Erosion Survey)
- Southern Leyte (Whitmore1984) as cited in Draft Philippine Plant Conservation Strategy.
- Mt. Pulag in Northern Luzon (Leonard Co, pers. comm.)
- Surigao del Norte, Northeastern Mindanao (areas overlying ultramafic rocks) (Edwino Fernando, pers. comm.)
- Naujan Lake, Mindoro Oriental: herbaceous marshland adjacent to the west of the lake (Arne Jensen pers. comm.)
- Pangasinan floodplains