The ecoregion is drained by several of New Guinea's large rivers, including the Mamberamo, Sepik, and Ramu, and Markham.

[citation needed] There are extensive freshwater swamp forests in the coastal lowlands and in the Lakes Plains region between the Van Rees-Foja mountains and the Central Range.

[6] The ecoregion corresponds to the Northern Papuan lowlands Endemic Bird Area.

Limited-range and endemic species include the red-breasted paradise kingfisher (Tanysiptera nympha), brown lory (Chalcopsitta duivenbodei), Edwards's fig parrot (Psittaculirostris edwardsii), Salvadori's fig parrot (Psittaculirostris salvadorii), Brass's friarbird (Philemon brassi), white-bellied whistler (Pachycephala leucogastra), brown-headed crow (Corvus fuscicapillus), pale-billed sicklebill (Drepanornis bruijnii), and banded yellow robin (Gennaeodryas placens).

[1] The largest is Mamberamo Foja Wildlife Reserve, which extends along the Mamberamo River and its tributaries the Tariku and Taritatu from the foothills of the Central Range to the sea, including the Foja Mountains.