Central Range montane rain forests


The Central Range montane rain forests is a tropical moist forest ecoregion on the island of New Guinea. The ecoregion covers the Central Range of the New Guinea Highlands, which extends along the spine of the island. The montane rain forests of the ecoregion are distinct from the surrounding lowland forests, and are home to many endemic plants and animals.

Geography

The ecoregion includes the montane rain forests of the Central Range, or Central Cordillera, between 1000 and 3000 metres elevation. The Central Range extends east and west across New Guinea, with the western portion of the range in Indonesia and the eastern portion in Papua New Guinea. The Central Range includes the Weyland Mountains at its western end, the Snow Mountains in Indonesia's Papua Province, the Star Mountains which span the Indonesia–Papua New Guinea border, and the Central and Eastern Highlands of Papua New Guinea.
The Bird's Neck Isthmus is at the western end of the Central Range. The isthmus' relatively low elevation separates the montane flora and fauna of the Central Range from those of the highlands on the Bird's Head and Bomberai peninsulas to the west.
Below 1000 metres, the montane forests transition to separate lowland forest ecoregions to the north, south, and west of the Central Range. The tree line is above 3000 metres elevation, above which are the high-elevation Central Range sub-alpine grasslands.

Climate

The climate of the highlands is humid and tropical. Rainfall exceeds 2500 mm annually in most of the highlands, and can exceed 7000 mm annually in the wettest areas. Temperatures average 18º C in the highlands, generally decreasing with elevation. Frosts are rare below 2800 meters elevation.
The region of heaviest rainfall is called the midaltitude fringe high rainfall zone, which extends along the south slope of the middle Central Range. It is characterized by continuously heavy rainfall, with more than 50 mm every week. The upper Ok Tedi watershed, on the south slope of the highlands near the boundary between Papua New Guinea and Indonesia, is the wettest part of the highlands, with over 7000 mm of rainfall annually.

Flora

There are three broad vegetation zones in the Central Range – lower montane forest, upper montane forest, and high mountain forest.
Lower montane forest extends from the lowland forest transition at approximately 1000 metres, up to 2,500 metres. Lower montane forest zone is characterized by trees in the beech family including Castanopsis acuminatissima and species of Lithocarpus, elaeocarps, and laurels. The conifers Araucaria cunninghamii var. papuana and Araucaria hunsteinii can form thick stands in some lower areas.
Upper montane forest occurs above 1500 m and is characterized by various evergreen species of southern beech, either in mixed stands with trees of other species or in pure stands, particularly on ridge crests and upper slopes. Mosses and other epiphytes cover the trees. The Central Range has the greatest diversity of species from Nothfagus subgenus Brassospora.
High mountain forest begins at approximately 2500 metres elevation, and extends to the tree line, in places extending to 3,900 m in the higher-elevation subalpine grasslands ecoregion. Characteristic trees are conifers – species of Podocarpus, Dacrycarpus, Dacridium, Papuacedrus, Araucaria, and Libocedrus – along with broadleaf trees in the myrtle family. High mountain forest generally has a thin canopy, lower than the upper montane forests, and thick understory.

Fauna

The ecoregion is home to 90 species of mammals, including marsupials, murid rodents, and bats. 44 species are endemic or near-endemic species whose ranges extend into neighboring ecoregions.
A range of Australasian tropical marsupials are native to the ecoregion, including tree kangaroos. Endemic marsupials include the speckled dasyure, great-tailed triok, Stein's cuscus, Telefomin cuscus, Weyland ringtail possum, and Pygmy ringtail possum. Near-endemic marsupial species include the red-bellied marsupial shrew black-tailed dasyure, Macleay's dorcopsis, mouse bandicoot, and Clara's echymipera.
Three bat species – the Telefomin roundleaf bat, New Guinea sheath-tailed bat, and small-toothed long-eared bat – are endemic. Near-endemic bat species include the Fly River roundleaf bat, Greater Papuan pipistrelle, Fly River trumpet-eared bat, Mantled mastiff bat, moss-forest blossom bat, and Bulmer's fruit bat. Bulmer's fruit bat is critically endangered.
Endemic murid rodents include short-haired water rat, mountain water rat, lesser small-toothed rat, red-bellied mosaic-tailed rat, large-scaled mosaic-tailed rat, white-toothed brush mouse, Giluwe rat, and Champion's tree mouse. Near-endemic and limited-range native murids include the large leptomys, mottled-tailed shrew mouse, eastern shrew mouse, one-toothed shew mouse, western water rat, earless water rat, mimic tree rat, Lorentz's mosaic-tailed rat, Shaw Mayer's brush mouse, lowland brush mouse, highland brush mouse, New Guinean rat, western white-eared giant rat, Shaw Mayer's water rat, and Ernst Mayr's water rat. Three murids - the large leptomys, eastern shrew mouse, and lesser small-toothed rat – are critically endangered.
348 bird species live in the ecoregion. 55 bird species are endemic or near endemic. Endemic bird species include the Papuan whipbird, sooty shrike-thrush, Snow Mountain munia, black-breasted munia, Archbold's bowerbird, short-tailed paradigalla, and King-of-Saxony bird-of-paradise. The ecoregion, together with the Central Range sub-alpine grasslands, constitutes the Central Papuan Mountains endemic bird area. Some of the near-endemic birds also range into the sub-alpine grasslands, and/or into other New Guinea mountain ranges.
Butterfly centres of endemism in the ecoregion include the Weyland Mountains, with nine endemic species, and the Hagen-Sepik-Wahgi Divide, with five endemic species.

Protected areas

14.3% of the ecoregion is in protected areas. They include: