Halmahera rain forests
Source: WWF WildFINDER
Introduction This ecoregion (Halmahera rain forests) comprises the original "Spice Islands." The tropical islands that constitute the complex and mountainous terrain of the Halmahera Rain Forests are an important part of the region known as Wallacea, which contains a very distinctive fauna representing a mix of Asian and Australasian species. This small ecoregion contains an astounding twenty-six bird species, including four monotypic genera, which are found nowhere else in the world. Although there is some exploitation by logging and mining companies, extensive blocks of habitat still cover all the islands, and nearly 80 percent of its original forest still intact.
Location and General Description
Halmahera, Indonesia Photograph by Vincent Roelofs This ecoregion represents the moist forests on Halmahera, Morotai, Obi, Bacan, and the other nearby Maluku Islands in the northeastern Indonesian Archipelago. Based on the Köppen climate zone system, this ecoregion falls in the tropical wet climate zone. The geologic history of these islands is a very complex mixture of inner volcanic island arcs, outer volcanic island arcs, raised coral reefs, and fragments of continental crust. Halmahera is a product of a collision between two islands approximately 1-2 million years ago. The eastern half of the island was part of an outer arc on the Philippines tectonic plate and consists of sedimentary and igneous rocks. The western half of Halmahera and Morotai was part of an inner arc consisting of volcanic materials. Bacan is a mixture of volcanic inner island arc and some crustal materials.
The natural vegetation of these islands was tropical lowland evergreen and semi-evergreen forest. Most of the remaining habitat in this ecoregion is semi-evergreen rain forest and includes eight characteristic dipterocarp species: Anisoptera thurifera, Hopea gregaria, H. iriana, H. novoguineensis, Shorea assamica, S. montigena, S. selanica, and Vatica rassak. Volcanic soils and good aspect combine to produce almost optimal growth conditions. Most of the trees reach 30 meters or more and carry thick-stemmed lianas and woody and herbaceous epiphytes. Rattans that grow to 130 meters (m) and other epiphytes are common in old-growth forests. The most luxuriant rain forests occur in northwest Morotai and north Halmahera, as opposed to the south arm of Halmahera, which is in the rain shadow of north Halmahera and Bacan. Low, shrubby vegetation is found in poor soil conditions on patches of ultrabasic rocks.
Source: WWF
Biodiversity Features
Overall diversity is low in this ecoregion, but overall endemism is moderate to high when compared with that of other ecoregions in Indo-Malaysia. This ecoregion falls within the Wallacean biogeographic zone, and thus exhibits a mixture of Asian and Australian fauna. Together with Seram, Buru, and the Banda Sea Islands, this island group forms part of a bioregion with perhaps the highest levels of bird endemism for its size anywhere in the world and the highest number of endemic birds of any area in Asia.
The mammal fauna is depauperate, containing only thirty-eight species with both Asian and Australasian affinities (cuscuses), but includes eight ecoregional endemics (Table 1). The Obi cuscus (Phalanger rothschildi) is considered vulnerable.
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Table 1. Endemic and Near-Endemic Mammal Species. Family Species Phalangeridae Phalanger ornatus* Phalangeridae Phalanger rothschildi* Phalangeridae Phalanger sp.* Pteropodidae Pteropus chrysoproctus Pteropodidae Pteropus personatus* Pteropodidae Nyctimene minutus Muridae Melomys obiensis* Muridae Rattus sp.* An asterisk signifies that the species' range is limited to this ecoregion. The ecoregion (Halmahera rain forests) supports approximately 223 bird species, including 43 ecoregional endemism|species]] (Table 2). The ecoregion corresponds with the Northern Maluku Endemic Bird Area (EBA). There are four endemic monotypic genera: Habroptila, Melitorgrais, Lycocorax, and Semioptera. These species include the invisible rail (Habroptila wallacii), white-streaked friarbird (Melitograis gilolensis), paradise-crow (Lycocorax pyrrhopterus), and the standardwing (Semioptera wallacii). Of the forty-three restricted-range species found in this ecoregion (and EBA), an astounding twenty-six are found nowhere else in the world. Five vulnerable species, four of which are found nowhere else, are found in the ecoregion: invisible rail (Habroptila wallacii), caranculated fruit-dove (Ptilinopus granulifrons), chattering lory (Lorius garrulus), and white cockatoo (Cacatua alba).
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