This lowland EBA extends from the south-east of Geelvink bay in the Indonesian province of Irian Jaya to the Huon peninsula in Papua New Guinea. Records of restricted-range birds are very scattered throughout the area but it is assumed to include coastal regions as well as the lower reaches of the Mamberamo-Idenburg- Rouffaer, Sepik-Ramu and Markham-Watut rivers. The EBA is separated from the North Papuan mountains (EBA 175), Adelbert-Huon ranges (EBA 177) and Central Papuan ranges (EBA 178) by the 1,000 m contour; the distributions of some restricted-range species from these different EBAs may overlap at their outer limits.

The habitat of this region is largely lowland rain forest, swamp forest and flooded alluvial forest, with patches of mangrove on the coast, areas of grassland and extensive swampy plains around the river systems, especially those of the Sepik and Ramu. Much of the area remains unexplored.

All the restricted-range species occur in lowland rain forest and some have been recorded in swamp/floodplain forest and in mangrove habitats. Philemon brassi was only discovered in 1939 in a small area of flooded canegrass and dense secondary forest around a lagoon on the Idenburg river, but has been recorded since from the lower Mamberamo river.

No species occurs throughout this large EBA , but there is sufficient overlap between the species' ranges for the area to qualify as a single EBA. Poecilodryas placens is very patchily distributed throughout New Guinea and in this EBA is known only from the Madang area.

Overall this region remains relatively undisturbed as it is inhabited by nomadic hunter-gatherer tribes-as elsewhere in New Guinea. There is, however, local settlement of an immigrant population in transmigration sites on the Indonesian side of the EBA (e.g. near Nabire and Jayapura, the capital of the province), and associated logging and land clearance. Potential additional threats come from a huge dam, which has been proposed for the Mamberamo gorge, as well as various other major timber and agricultural schemes (K. D. Bishop in litt. 1996). The construction of the Trans-Irian Highway, to connect Jayapura and Wamena, will speed up the development of this area by giving improved access (Sujatnika et al. 1995).

One species which appears to be particularly susceptible to developing timber schemes and to the depredations of the local parrot trade is Psittaculirostris salvadorii (Beehler 1985, K. D. Bishop in litt. 1996). Northern Cassowary Casuarius unappendiculatus, New Guinea Harpy Eagle Harpyopsis novaeguineae and Victoria Crowned-pigeon Goura victoria are widespread threatened species (all classified as Vulnerable) which occur in this EBA, and all are susceptible to hunting wherever access to their habitat is increased.

The lowland forest and floodplains of the Mamberamo and Idenburg are within the boundaries of the Foja Nature Reserve, which is Indonesia's second largest terrestrial conservation area, with a total area of c.10,000 km². Additional lowland areas in central-north Irian Jaya are covered by the Jayawijaya Wildlife Sanctuary (8,000 km²) (Sujatnika et al. 1995; see also WWF/IUCN 1994-1995).

In Papua New Guinea the middle Sepik, Sepik delta, middle Ramu, Ramu basin, and Watut hills and watershed have been identified by Beehler (1993) as sites which are important for terrestrial and wetland biodiversity.

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Northern Papuan lowlands. Downloaded from https://datazone.birdlife.org/eba/factsheet/176 on 22/11/2024.