Southeastern Asia: Eastern Papua New Guinea

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The Huon Peninsula Montane Rain Forests [AA0107] consist of tropical montane forest surrounded by ocean and lowland forest on a rugged peninsula. The Finisterre Range, representing a third of the ecoregion, supports more mainland endemic species of warm-blooded vertebrates than any similar-sized area in PNG. The ecoregion's isolation has led to a high degree of endemism, and the area is still relatively intact.

  • Scientific Code
  • Ecoregion Category
  • Size
    6,400 square miles
  • Status
    Relatively Stable/Intact
  • Habitats

Location and General Description
The Huon Peninsula Montane Rain Forests [AA0107] are made up of the tropical montane moist forests (from 1,000 m to 3,000 m) of the Huon Peninsula in PNG, on the island of New Guinea. There are three mountain ranges on the peninsula: the Finisterre (to 4,176 m), Saruwaged (to 4,122 m), and Cromwell and Rawlinson ranges. 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). This portion of New Guinea is a very active tectonic area with a complex geologic history (Bleeker 1983). The surface geology of this ecoregion is a combination of Miocene siltstone, conglomerate, volcanics, and limestone (Bleeker 1983). The Finisterre Range in particular consists of one steep ridge of limestone (Davis et al. 1995).

The vegetation of this ecoregion is mostly tropical wet evergreen forest (hill type), with a large percentage of tropical montane evergreen forest and a small amount of limestone forest (MacKinnon 1997; Paijmans 1975). Some of the higher peaks contain ecologically fragile high alpine areas, which are part of the adjoining Central Ranges sub-alpine grassland ecoregion.

The somewhat low-canopy, closed lowland hill forest contains more open shrub layer but a denser herbaceous layer than lower-elevation alluvial forest. Palms are fewer in number. The dominant canopy trees include species of Pometia, Canarium, Anisoptera, Cryptocarya, Terminalia, Syzygium, Ficus, Celtis, Dysoxylum, and Buchanania. Koompassia, Dillenia, Eucalyptopsis, Vatica, and Hopea are locally abundant. Dense stands of Araucaria, the tallest tropical trees in the world, are present in scattered locations (Paijmans 1975; Nightingale 1992).

Although they are subject to variable climates and topography, montane forests are smaller crowned and have more even 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, Ilex, and southern conifers. Nothofagus and Araucaria may grow in pure, dense stands. The levels of Myrtaceae, Elaeocarpaceae, and conifers increase with altitude. The conifers, which are generally found above 2,000 m, include Dacrycarpus, Podocarpus, Phyllocladus, and Papuacedrus in the canopy and emergent layer (Paijmans 1975).

The Cromwell Range contains extensive Dacrydium forests (Miller et al. 1994). In the lower montane forests of the Cromwell Range, up to elevations of 2,000 m, Castanopsis and Lithocarpus predominate. Above 2,000 m, Xanthomyrtus-Vaccinium-Rhododendron communities are found, and Lithocarpus-Elmerrillia forest is present at approximately 2,300 m. Above 2,400 m, Elaeocarpus and conifers (Phyllocladus, Podocarpus, and Dacrydium) dominate (Davis et al. 1995).

Biodiversity Features
Overall richness is moderate to high and overall endemism is low to moderate when compared with those of other ecoregions in Indo-Malaysia; however, the Finisterre Range, representing a third of the ecoregion, supports more mainland endemic species of warm-blooded vertebrates than any similar-sized area in PNG (Beehler 1993).

The mammalian fauna consists of a wide variety of tropical Australasian marsupials, including tree kangaroos. There are eighty-one mammal species in this ecoregion, including six species that are endemic or near endemic (table 1). The Huon tree-kangaroo (Dendrolagus matschiei) is found nowhere else on Earth and is considered endangered. The ecoregion also contains the widespread but endangered Papuan long-beaked echidna (Flannery 1995; Flannery and Groves 1998; Bonaccorso et al., in press; IUCN 2000).

Table 1. Endemic and Near-Endemic Mammal Species.

Family Species
Macropodidae Dendrolagus matschiei*
Muridae Pogonomelomys mayeri
Muridae Abeomelomys sevia
Muridae Rattus novaeguineae
Muridae Leptomys ernstmayeri
Muridae Melomys gracilis

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

The avifauna of the ecoregion has a clear Australasian flavor, with representatives of several Australasian families including Ptilonorhynchidae, Eopsaltridae, Meliphagidae, and Paradisaeidae. The ecoregion basically corresponds with the Adelbert and Huon ranges EBA, although the small Adelbert Mountain Range is not part of this ecoregion. The EBA contains eleven restricted-range species, ten of which are found in the ecoregion. The ecoregion contains a total of sixteen endemic and near-endemic species (table 2), including the vulnerable Wahnes's parotia (Parotia wahnesi) (Beehler et al. 1986; Coates 1985; Stattersfield et al. 1998). The ecoregion is virtually unstudied ornithologically (Stattersfield et al. 1998).

Table 2. Endemic and Near-Endemic Bird Species.

Family Common Name Species
Psittacidae Edwards's fig-parrot Psittaculirostris edwardsii
Psittacidae Madarasz's tiger-parrot Psittacella madaraszi
Loriidae Brown lory Chalcopsitta duivenbodei
Caprimulgidae Mountain eared-nightjar Eurostopodus archboldi
Apodidae Papuan swiftlet Aerodramus papuensis
Meliphagidae Olive-streaked honeyeater Ptiloprora meekiana
Meliphagidae Rufous-backed honeyeater Ptiloprora guisei
Meliphagidae Cinnamon-browed honeyeater Melidectes ochromelas
Meliphagidae Huon wattled honeyeater Melidectes foersteri
Meliphagidae Spangled honeyeater Melipotes ater
Cinclosomatidae Brown-capped jewel-babbler Ptilorrhoa geislerorum
Cinclosomatidae Blue-capped ifrita Ifrita kowaldi
Paradisaeidae Wahnes's parotia Parotia wahnesi
Paradisaeidae Huon astrapia Astrapia rothschildi
Paradisaeidae Emperor bird-of-paradise Paradisaea guilielmi*
Motacillidae Alpine pipit Anthus gutturalis

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

This ecoregion, with one endemic butterfly species, is a center of butterfly endemicity on the island of New Guinea (Parsons 1999).

The Finisterre Range and Huon Peninsula Centres of Plant Diversity are located in this ecoregion. The Cromwell Ranges are the only extensive unlogged Dacrydium forests in the Southern Hemisphere (Davis et al. 1994; Miller et al. 1994).

Current Status
Except for some forest loss along the southern part and the Buweng Timber Rights Purchase (using helicopters), most of the ecoregion's natural habitat is intact (Johns 1993). The Huon Highlands are a major wilderness area (Beehler 1994). The two large protected areas (Finisterre and Mt. Bangeta) cover about 18 percent of the ecoregion area (table 3).

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

Protected Area Area (km2) IUCN Category
Finisterre [AA1002] 2,290 ?
Mt. Bangeta [AA1002] 550 ?
Total 2,840  

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

Types and Severity of Threats
The threats to this ecoregion are minimal at present. Most of the forests remain unthreatened by further degradation. However, certain alpine highlands and hill tracts are threatened by development (Miller et al. 1994).

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 montane evergreen forests in the Huon Peninsula were delineated as another distinct ecoregion, the Huon Peninsula Montane Rain Forests [AA0107], and correspond to MacKinnon's (1997) biounit P3k. 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 ecoregions.