Northern portion of the island of New Guinea

The inaccessible, isolated mountain ranges of the Northern New Guinea Montane Rain Forests [AA0116], surrounded by tropical lowland forest, are home to unique vertebrate species found nowhere else on Earth. Some portions of this ecoregion are poorly known. In fact, the Foya Mountains, a significant piece of upland east of the Mamberamo River, have no record of visitation of any kind before 1979 (Stattersfield et al. 1998). Because of their isolation, they are relatively intact.

  • Scientific Code
  • Ecoregion Category
  • Size
    9,000 square miles
  • Status
  • Habitats

Location and General Description
This ecoregion is composed of the isolated montane forests (more than 1,000 m) of the Van Rees (to 1,430 m) and Gauttier (Foya) (to 2,193 m), Cyclops (to 2,158 m), Denake, Bewani (to 2,000 m), Torricelli (to 1,650 m), Prince Alexander (to 1,240 m), and Adelbert Ranges (to 1,718 m) in Irian Jaya, Indonesia and PNG. These isolated mountain ranges are all on the northern side of the Central Cordillera of the island of New Guinea. The climate of the ecoregion is tropical wet, which is characteristic of this part of Melanesia, located in the western Pacific Ocean north of Australia (National Geographic Society 1999). Northern New Guinea is a very active tectonic area with a complex geologic history (Bleeker 1983). The geology of this mountainous ecoregion is a mixture of metamorphic and Pliocene fine-grained terrestrial and marine sediments (Bleeker 1983; Petocz 1989).

The vegetation of this ecoregion is generally tropical montane rain forest. Although they are subject to variable climates and topography, montane forests are smaller-crowned and have even more canopies than lowland hill forest. Tree densities can be high, and the shrub density is also high. Predominant canopy trees include Nothofagus, Lauraceae, Cunoniaceae, Elaeocarpaceae, Lithocarpus, Castanopsis, Syzygium, Illex, and southern conifers. Nothofagus and Araucaria may grow in pure, dense stands. The levels of Myrtaceae, Elaeocarpaceae, and conifers increase with altitude. The conifers generally found above 2,000 m include Dacrycarpus, Podocarpus, Phyllocladus, and Papuacedrus in the canopy and emergent layer (Paijmans 1975).

The open forests of the Cyclops Mountains, perhaps the most well-studied of the ranges, are dominated by Kania, Metrrosideros, and Xanthmyrtus, with Lithocarpus and Nothofagus at higher altitudes. Above 1,400 m, conifers (Phyllocladus, Papuacedrus, Dacrydium) dominate, with Podocarpus and Rapanea (R. Johns, pers. comm., 2000). At an elevation of 1,200 m, the Foya Mountains to the west are dominated by Araucaria cunninghammii, Podocarpus neriifolius, Agathis labillardieri, Calophyllum, and Palaquium. The Torricelli, Bewani, and Prince Alexander ranges consist of limestone and montane forest (Davis et al. 1995).

Biodiversity Features
Overall richness and endemism are low to moderate when compared with those of other ecoregions in Indo-Malaysia. There are fifty-one mammal species in the ecoregion, with six species that are endemic or near endemic (Flannery 1995; Flannery and Groves 1998) (table 1). The mammalian fauna consists of a wide variety of tropical Australasian marsupials, including tree kangaroos, and a glider (Flannery 1995). The Cyclops long-beaked echidna (Zaglossus attenboroughi) was considered endangered before it was split from the Papuan echidna (Zaglossus bruijnii) (IUCN 2000), and presumably would still be considered so because it is a focal prey item for humans (Flannery 1995; Flannery and Groves 1998; Bonaccorso et al., in press). The northern glider (Petaurus abidi) is found nowhere else on Earth (Ziegler 1981). The highlands of the north coastal ranges also harbor Scott's tree kangaroo (Dendrolagus scottae), reputed to be the largest and most threatened native forest mammal in PNG (Beehler 1994).

Table 1. Endemic and Near-Endemic Mammal Species.

Family Species
Tachyglossidae Zaglossus attenboroughi*
Perorictidae Echymipera clara
Petauridae Petaurus abidi*
Macropodidae Dendrolagus scottae*
Muridae Paraleptomys rufilatus
Muridae Xenuromys barbatus

An asterisk signifies that the species' range is limited to this ecoregion.

This area also provides habitat for a number of isolated and taxonomically distinct bird populations. The avifauna of the ecoregion has a clear Australasian flavor, including representatives of several Australasian families including Ptilonorhynchidae, Eopsaltridae, Meliphagidae, and Paradisaeidae. This ecoregion includes all of the North Papuan Mountains EBA and portions of the Adelbert and Huon ranges EBA (the Adelbert Mountains) and the North Papuan lowlands EBA (the Van Rees Mountains) (Stattersfield et al. 1998). The ecoregion contains twelve endemic or near-endemic birds (Beehler et al. 1986; Coates 1985) (table 2). The North Papuan mountains EBA contains five restricted-range birds, including three found nowhere else on Earth. The Adelbert Range contains three restricted-range bird species. It shares Wahnes's parotia (Parotia wahnesi) and the olive-streaked honeyeater (Ptiloprora guisei) with the mountains of the Huon Peninsula, but the fire-maned bowerbird (Sericulus bakeri) is found nowhere else on Earth but this ecoregion (Stattersfield et al. 1998). The rarest bird species in PNG, fire-maned bowerbird has the most circumscribed geographic range known for any species on mainland PNG (Miller et al. 1994). Both the fire-maned bowerbird and Wahnes's parotia (Parotia wahnesi) are considered vulnerable (IUCN 2000).

Table 2. Endemic and Near-Endemic Bird Species.

Family Common Name Species
Rallidae Mayr's forest-rail Rallina mayri*
Ptilonorhynchidae Golden-fronted bowerbird Amblyornis flavifrons*
Ptilonorhynchidae Fire-maned bowerbird Sericulus bakeri*
Meliphagidae Mayr's honeyeater Ptiloprora mayri*
Meliphagidae Rufous-backed honeyeater Ptiloprora guisei
Meliphagidae Cinnamon-browed honeyeater Melidectes ochromelas
Eopsaltriidae Smoky robin Peneothello cryptoleucus
Eopsaltriidae Green-backed robin Pachycephalopsis hattamensis
Cinclosomatidae Brown-capped jewel-babbler Ptilorrhoa geislerorum
Paradisaeidae Greater melampitta Melampitta gigantea
Paradisaeidae Carola's parotia Parotia carolae
Paradisaeidae Wahnes's parotia Parotia wahnesi

An asterisk signifies that the species' range is limited to this ecoregion.

Within this ecoregion, the Torricelli Range has one endemic butterfly species, making it a center of butterfly endemicity on the island of New Guinea (Parsons 1999).

Several Centres of Plant Diversity correspond with the various ranges of this ecoregion, including the Mamberamo-Pegunungan Jayawijay (Van Rees and Gauttier) and Cagar Alam Pegunungan Cyclops in Irian Jaya, the Torricelli Mountains-Bewani Mountains-Prince Alexander Range in PNG, and the Adlebert Range in PNG. The Torricelli, Bewani, and Prince Alexander ranges have a flora that is estimated to exceed 2,000 species and includes the only endemic fern genus on New Guinea (Rheopteris cheesmannii) (Davis et al. 1995).

Several endemic plants have been collected in the Cyclops Mountains, but in general the flora of this ecoregion is very poorly known. Ultrabasic formations are present in the Makanoi Range forests (R. Johns, pers. comm., 2000).

Current Status
Much of the topography of this ecoregion is too steep for traditional logging activities, and the majority of the ecoregion is safe because of its inaccessibility. Twenty-six percent of the ecoregion is covered by five protected areas, mostly in Irian Jaya, although almost half of the ecoregion is in PNG (MacKinnon 1997) (table 3).

Table 3. WCMC (1997) Protected Areas That Overlap with the Ecoregion.

Protected Area Area (km2) IUCN Category
Unnamed [AA0115] 1,510 ?
Mamberamo-Pegunungan Foya [AA0115] 2,110 IV
Peg. Cycloop 210 I
Teluk Yotefa 90 IV
Mt. Menawa 2,150 ?
Total 6,070  

Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets.

Types and Severity of Threats
The threats to this ecoregion include the potential for commercial logging if it becomes economically viable. The Cyclops Mountains are quite close to the main population center of Irian Jaya, Jayapura, however, and these hill forests are at risk from the town and a transmigration settlement in the area (Stattersfield et al. 1998).

Justification of Ecoregion Delineation
Using Whitmore's (1984) map of the vegetation of Malesia and MacKinnon's (1997) reconstruction of the original vegetation, we delineated the large areas of distinct habitat types as ecoregions. The tropical lowland moist and freshwater swamp forests to the north of the Central Cordillera were placed in the Northern New Guinea Lowland Rain and Freshwater Swamp Forests [AA0115], and the montane forests in the Northern New Guinea Montane Rain Forests [AA0116] (based largely on recommendations by Bob Johns, pers. comm., 1999). This ecoregion corresponds to MacKinnon's (1997) biounits P3e and P3j. Udvardy (1975) placed these ecoregions in the Papuan biogeographic province of the Oceanian Realm.

References for this ecoregion are currently consolidated in one document for the entire Indo-Pacific realm.
Indo-Pacific Reference List

Prepared by: John Morrison
Reviewed by:

This text was originally published in the book Terrestrial ecoregions of the Indo-Pacific: a conservation assessment from Island Press. This assessment offers an in-depth analysis of the biodiversity and conservation status of the Indo-Pacific's