Central Range sub-alpine grasslands
Papua New Guinea. (Photograph by John Morrison)
The Central Range sub-alpine grasslands are a unique example of alpine shrublands surrounding the highest peaks (up to 4884 metres) in Australasia. These fragile environments are fairly well protected by a combination of formal protection and remoteness.
Location and General Description
This ecoregion is made up of scattered alpine meadow habitats above 3,000 meters (m) along the Central Cordillera in Irian Jaya, Indonesia and Papua New Guinea (PNG). The Central Cordillera is composed of a series of mountain ranges, which are broadly grouped into the Snow Mountains in Irian Jaya, the Star Mountains in Irian Jaya and PNG, and the Central and Eastern Highlands PNG. Although most of New Guinea has a tropical wet climate, in the case of this ecoregion it is modified by extreme altitude. Another classification system puts this ecoregion in a humid upper montane climate. The surface geology of the Central Cordillera is composed of metamorphic and intrusive igneous rocks, along with some sedimentary formations.
The vegetation of the ecoregion consists of alpine meadow, montane, and upper montane tropical evergreen forest. Vegetation in the Central Ranges varies with elevation, local climate, aspect, and substrate. Upper montane forest consists of conifers (Podocarpus, Dacrycarpus, Dacridium, Papuacedrus, Araucaria, and Libocedrus) and Myrtacae, with a thin canopy and prominent understory. Above the montane forest, at approximately 3,000 m, the vegetation abruptly changes, and the high plateau areas of the cordillera are interspersed with tree fern (Cyathea) savannas, bogs, and grasslands. Immediately below the alpine zone, the vegetation typically is low shrubs and Deschampsia tussock grasslands. Heaths of Rhododendron, Vaccinium, Coprosma, Rapanea, and Saurauia form the limit of sub-alpine forest. The alpine habitat above 4,000 m consists of compact herbs such as Ranuculus, Potentilla, Gentiana, and Epilobium, the grasses Poa and Deschampsia, and bryophytes and lichens. Rosette and cushion herbs, mosses, lichens, and low ferns become progressively more abundant with altitude and replace grasses above 4,300 m. The highest areas are capped by snow and ice fields.
Biodiversity Features
With the exception of plant endemism, overall richness and endemism of this ecoregion are low when compared with those of other ecoregions in Indo-Malaysia.
Table 1. Endemic and Near-Endemic Mammal Species. Family Species Dasyuridae Antechinus wilhelmina Muridae Pseudohydromys occidentalis* Muridae Stenomys richardsoni* Muridae Mallomys gunung* An asterisk signifies that the species' range is limited to this ecoregion. This extreme environment is inhabited by only nine mammals, consisting of four murid rodents, two microchiropteran bats, and three marsupials: a tree kangaroo, a cuscus, and an antechinus. Of these mammals, four are endemic or near endemic (Table 1). The western shrew mouse (Pseudohydromys occidentalis) and Doria's tree-kangaroo (Dendrolagus dorianus) are considered vulnerable. Eighty-four bird species inhabit this ecoregion (Central Range sub-alpine grasslands) , of which an amazing twenty-eight species are endemic or near-endemic (Table 2). The Central Range sub-alpine grasslands constitute the upper elevations of the Central Papuan Mountains Endemic Bird Area (EBA), which it shares with the Central Range montane rain forests ecoregion. Although the entire EBA contains fifty-four restricted-range species, only twenty-four of these range into the sub-alpine grasslands. The long-bearded honeyeater (Melidectes princeps), MacGregor's bird-of-paradise (Macgregoria pulchra), the ribbon-tailed astrapia (Astrapia mayeri) are considered vulnerable. {| border="1" cellpadding="3" align="right" ! colspan="3" align="center" | Table 2. Endemic and Near-Endemic Bird Species. Family Common Name Species Phasianidae Snow Mountain quail Anurophasis monorthonyx* Psittacidae Painted tiger-parrot Psittacella picta Aegothelidae Archbold's owlet-nightjar Aegotheles archboldi Motacillidae Alpine pipit Anthus gutturalis Acanthizidae Papuan thornbill Acanthiza murina Eopsaltriidae Greater ground-robin Amalocichla sclateriana Eopsaltriidae Snow Mountain robin Petroica archboldi* Eopsaltriidae Alpine robin Petroica bivittata Cinclosomatidae Blue-capped ifrita Ifrita kowaldi Pachycephalida Black sittella Daphoenositta miranda Pachycephalida Lorentz's whistler Pachycephala lorentzi Meliphagidae Orange-cheeked honeyeater Oreornis chrysogenys Meliphagidae Short-bearded honeyeater Melidectes nouhuysi* Meliphagidae Long-bearded honeyeater Melidectes princeps* Meliphagidae Huon wattled honeyeater Melidectes foersteri Meliphagidae Spangled honeyeater Melipotes ater Meliphagidae Sooty honeyeater Melidectes fuscus Meliphagidae Belford's honeyeater Melidectes belfordi Meliphagidae Rufous-backed honeyeater Ptiloprora guisei Meliphagidae Black-backed honeyeater Ptiloprora perstriata Estrildidae Mountain firetail Oreostruthus fuliginosus Paradisaeidae Crested bird-of-paradise Cnemophilus macgregorii Paradisaeidae MacGregor's bird-of-paradise Macgregoria pulchra Paradisaeidae Brown sicklebill Epimachus meyeri Paradisaeidae Princess Stephanie's astrapia Astrapia stephaniae Paradisaeidae Splendid astrapia Astrapia splendidissima Paradisaeidae Ribbon-tailed astrapia Astrapia mayeri Paradisaeidae Huon astrapia Astrapia rothschildi An asterisk signifies that the species' range is limited to this ecoregion. Five Centres of Plant Diversity (CPD) are shared between this ecoregion (Central Range sub-alpine grasslands) and the adjacent Central Range montane rain forests ecoregion. The Star Mountains-Telefomin-Tifalmin-Strickland Gorge CPD in PNG contains very rich (more than 3,000 vascular plant species) montane and high-altitude vegetation. Alpine communities are found on the summit of Mt. Giluwe, in the Mt. Giluwe-Tari Gap-Doma Peaks CPD. The poorly known Kubor Ranges in PNG contain extensive areas of high-altitude vegetation, and many endemics are likely to exist on the limestone and volcanic ash. The Bismarck Falls-Mt. Wilhelm-Mt. Otto-Schrader Range-Mt. Hellwig-Gahavisuka CPD has a wide variety of vegetation types and contains more than 5,000 vascular plant species. There are numerous endemics already known from the sub-alpine and alpine areas of Mt. Wilhelm, the highest point in PNG. ==Current Status== The eleven protected areas that extend into this small ecoregion cover 7,290 square kilometers (km2), representing more than 47 percent of the ecoregion area (Table 3). A gap analysis, based on detailed vegetation and habitat type mapping, has never been performed to determine whether the existing protected area network adequately covers all habitats with protected areas that are large enough to maintain all critical ecological processes.  Mt. Wilhelm, Papua New Guinea. (Photograph by John Dumbacher) |
|---|
