The Buru Rain Forests are located on the small mountainous tropical island of Buru in the Banda Sea, part of the region known as Wallacea, which contains a distinctive fauna representing a mix of Asian and Australasian species. There are ten bird species in this ecoregion that are found nowhere else on Earth, including a monotypic bird genus. Although the northern portions of the island have been degraded by repeated burning and the coastal lowlands have been cleared, the remaining forest forms two large, contiguous blocks, current threats appear to be low, and the conservation outlook is relatively stable.

Location and General Description

Satellite view of Buru Island, Indonesia. (Photograph by USGS)

This ecoregion represents the moist forests in the island of Buru. Based on the Köppen climate zone system, this ecoregion falls in the tropical wet climate zone. Buru is part remnant crustal fragment, probably from the Australian continent, and part of the volcanic Inner Banda Arc. Consequently, the surface geology of Buru is complex, consisting of older metamorphic schists and metamorphic gneiss, younger volcanics, and recent alluvium.

The natural vegetation of the island was tropical lowland evergreen and semi-evergreen rain forests. The dominant tree species in this moist forest are the dipterocarps, Anisoptera thurifera, Hopea gregaria, H. iriana, H. novoguineensis, Shorea assamica, S. montigena, S. selanica, and Vatica rassak. In old-growth forests, the larger trees grow to more than 30 meters (m) in height and tend to be covered with thick-stemmed lianas and other piphytes. Open forest, woodland, and savanna are also found in this ecoregion, with some being natural but most originating from human activity. The fire-resistant paper bark tree (Melaleuca cajuputi) is common and grows in nearly monotypic stands in dry areas. The steep limestone cliffs in the northwestern part of the ecoregion are covered by mixed forests that include Shorea spp. Exposed ridges between 1,800 and 2,000 m above sea level are characterized by stunted Dacrydium novo-guineense.

Biodiversity Features

Overall richness and endemism in this ecoregion are low to moderate when compared with those of other ecoregions in Indo-Malaysia. Being in the Wallacean biogeographic zone, the ecoregion contains a mixture of Asian and Australian fauna. The mountainous areas of this island are largely unexplored and may contain many undiscovered species.

The known mammal fauna of Buru consists of at least twenty-five species, including four near endemics (Table 1). Two of these species are globally threatened: the vulnerable Seram flying-fox (Pteropus ocularis) and lesser tube-nosed fruit bat (Nyctimene minutus).

The bird fauna consists of 178 species, including twenty-nine endemic or near-endemic species (Table 2). The ecoregion corresponds with the Buru Endemic Bird Area (EBA) and contains twenty-eight restricted-range bird species, ten of which are found nowhere else on Earth. Six of these species are considered vulnerable: Moluccan scrubfowl (Megapodius wallacei), blue-fronted lorikeet (Charmosyna toxopei), black-lored parrot (Tanygnathus gramineus), Buru cuckoo-shrike (Coracina fortis), streaky-breasted jungle-flycatcher (Rhinomyias addita), and rufous-throated white-eye (Madanga ruficollis), which represents a monotypic genus.

Buru's butterflies include a large number of endemics and are therefore accorded highest conservation priority. Pifridae has 25 percent of the local species unique to Buru, and Papilionidae 7 percent.

Current Status

The coastal lowland forests have been cleared, and the northern and northeastern portions of the island now contain monsoon forest, gallery forest, and savannas as a result of repeated burning. However, the remaining upland forest forms two large, contiguous blocks. Most of this forest is a mosaic of primary and secondary forest as a result of shifting cultivation.

The two protected areas—of which one is greater than 1,000 square kilometers (km²)—cover 17 percent of the ecoregion (Table 3). Commercial logging on Buru intensified during the 1970s, but much of the island is still under extensive forest cover.

Types and Severity of Threats

Current threats to this ecoregion are low, causing its conservation status to remain vulnerable. Commercial logging and shifting cultivation are the primary threats to the remaining habitat.

Justification of Ecoregion Delineation

The Sula Islands were included within the Sulawesi lowland rain forests and the Aru Islands in the Vogelkop-Aru lowland rain forests. Buru Island, identified as a distinct subunit (13c) by MacKinnon and as an Endemic Bird Area (EBA), was delineated as a distinct ecoregion, the Buru Rain Forests. Seram, the larger island to the east of Buru, was also delineated as an ecoregion: Seram rain forests. The larger Halmahera rain forests includes Obi Island, which MacKinnon recognized as a separate subunit (13b) from Halmahera Island (subunit 13a). We created the Banda Sea Islands moist deciduous forests by combining the islands in the Kai and Tanimbar archipelagos, which Monk et al. distinguished as a biogeographic unit. The primary vegetation on the islands in both these archipelagos is moist deciduous forests and semi-evergreen forests, whereas the vegetation in the other, nearby large islands (Seram and Aru) is evergreen rain forests.

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