Current view: Text account
Site description (2001 baseline):
Site location and context
Agusan Marsh is near Bunawan in the interior of north-eastern Mindanao Island, Agusan del Sur Province. It is a vast complex of freshwater marshes and watercourses with numerous small shallow lakes and ponds in the upper basin of the Agusan River and its tributaries. The rivers rise in the hills of eastern Mindanao and cause extensive flooding in the marshes from November to March.
The main habitats of the marsh include freshwater swamp forest (c.49%), secondary scrub (c.14%), herbaceous swamp (c.7%), freshwater lakes, pools and rivers (c.10%), rice paddies and other agricultural land (c.6%) and small settlements (c.6%). Some parts of the marsh have been converted into fishponds. The main economic activities in the marsh are fishing, aquaculture and agriculture (mainly rice and cash crops), but the region is sparsely populated because of the annual flooding of the Agusan River.
The marsh is an important source of water for irrigation. It has an important hydrological function, holding excess water at times of high flow, and ensuring adequate flow during dry periods. If the marsh were to be drained, the communities downstream would be prone to serious floods and droughts.
This IBA is important for a variety of waterbirds, notably herons and egrets. Several threatened species have been recorded in or near to Agusan Marsh in the past, mainly forest birds, but it is unclear whether they have significant populations in the remaining forests there. However, Silvery Kingfisher has recently been recorded in the marsh itself, and there may be a significant population of Philippine Duck there.
Non-bird biodiversity: The marshes support the largest population of the Estuarine Crocodile Crocodylus porosus remaining in the Philippines, and it has been suggested that the endangered Philippine Crocodile C. mindorensis may also be present
Agusan Marsh is near Bunawan in the interior of north-eastern Mindanao Island, Agusan del Sur Province. It is a vast complex of freshwater marshes and watercourses with numerous small shallow lakes and ponds in the upper basin of the Agusan River and its tributaries. The rivers rise in the hills of eastern Mindanao and cause extensive flooding in the marshes from November to March.
The main habitats of the marsh include freshwater swamp forest (c.49%), secondary scrub (c.14%), herbaceous swamp (c.7%), freshwater lakes, pools and rivers (c.10%), rice paddies and other agricultural land (c.6%) and small settlements (c.6%). Some parts of the marsh have been converted into fishponds. The main economic activities in the marsh are fishing, aquaculture and agriculture (mainly rice and cash crops), but the region is sparsely populated because of the annual flooding of the Agusan River.
The marsh is an important source of water for irrigation. It has an important hydrological function, holding excess water at times of high flow, and ensuring adequate flow during dry periods. If the marsh were to be drained, the communities downstream would be prone to serious floods and droughts.
Pressure/threats to key biodiversity
Clear cutting of forests in the water catchment area of Agusan Marsh, including the Diwata Mountains of Surigao del Sur to the east and the mountains of Bukidnon and Davao del Norte to the south, has resulted in severe flooding and increased rates of sedimentation in the wetland.
Parts of the marsh have already been converted into aquaculture ponds and agricultural land. Proposed development projects in the water catchment area include the construction of dams and reservoirs for hydroelectric power, flood control and irrigation purposes. Other pressures on this IBA include the collection of forest products, mercury pollution from small-scale mining, and the hunting of birds. The crocodiles are also heavily persecuted.
Conservation responses/actions for key biodiversity
It has also been suggested that the area could be made into a crocodile sanctuary if the local inhabitants could be convinced that they could ranch or crop crocodiles on a sustained yield basis.
Surveys are required in this IBA, to investigate both the extent and quality of the remaining habitats and the current status of the threatened and restricted-range birds and congregatory waterbirds.
Agusan Marsh Wildlife Sanctuary was declared by Presidential Proclamation 913 in 31 October 1996. The area was given Ramsar site status in 1999.
It is a GEF CPPAP site (including Esperanza).
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Agusan marsh (Philippines). Downloaded from
https://datazone.birdlife.org/site/factsheet/agusan-marsh-iba-philippines on 23/12/2024.
