Introduction

The Huon Peninsula Montane Rain Forests 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.

Location and General Description

Mt. Bangeta, Papua New Guinea. (Photograph by David Olson)

The Huon Peninsula Montane Rain Forests are made up of the tropical montane moist forests (from 1,000 meters (m) to 3,000 meters) 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. This portion of New Guinea is a very active tectonic area with a complex geologic history. The surface geology of this ecoregion is a combination of Miocene siltstone, conglomerate, volcanics, and limestone. The Finisterre Range in particular consists of one steep ridge of limestone.

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. 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.

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.

The Cromwell Range contains extensive Dacrydium forests. 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.

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.

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.

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 Endemic Bird Area (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). The ecoregion is virtually unstudied ornithologically.

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

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.

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. The Huon Highlands are a major wilderness area. The two large protected areas (Finisterre and Mount Bangeta) cover about 18 percent of the ecoregion area (Table 3).

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.

Jusification 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, and correspond to MacKinnon's (1997) biounit P3k. Udvardy (1975) placed these ecoregions in the Papuan biogeographic province of the Oceanian Realm.

Additional Information on this Ecoregion

• For a shorter summary of this entry, see the WWF WildWorld profile of this ecoregion.
• To see the species that live in this ecoregion, including images and threat levels, see the WWF Wildfinder description of this ecoregion.
• World Wildlife Fund Homepage