Agusan marsh

Country/territory: Philippines

IBA criteria met: A1, A2, A4i (2001)
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Area: 19,197 ha

Haribon Foundation
IBA conservation status
Year of assessment (most recent) State (condition) Pressure (threat) Response (action)
2001 not assessed high not assessed
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Site description (2001 baseline)
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.

Key biodiversity
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

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Agusan marsh. Downloaded from on 03/12/2023.