Timor and Wetar deciduous forests

The Timor and Wetar deciduous forests is a tropical dry forest ecoregion in Indonesia and East Timor. The ecoregion includes the islands of Timor, Wetar, Rote, Savu, and adjacent smaller islands.

Timor and Wetar deciduous forests
Corypha utan palms in hilly savanna near Ayotupas, West Timor
Ecology
RealmAustralasian realm
Biometropical and subtropical dry broadleaf forests
Geography
Area33,091 km2 (12,777 sq mi)
CountriesIndonesia and East Timor
Provinces of IndonesiaEast Nusa Tenggara and Maluku
Conservation
Conservation statusCritical/endangered
Protected2,245 km² (7%)[1]

Geography

Timor, Wetar, Rote, and Savu are part of the Lesser Sunda Islands. The ecoregion is part of Wallacea, a group of islands that are part of the Australasian realm, but were never joined to either the Australian or Asian continents. The islands of Wallacea are home to a mix of plants and animals from both terrestrial realms, and have many unique species that evolved in isolation.[2]

Timor is the largest of the islands at 30,777 km². Timor is politically divided; The independent country of Timor Leste is on the eastern portion of Timor, and western Timor and the other islands are part of Indonesia. Western Timor, Rote, and Savu are part of East Nusa Tenggara province, while Wetar is part of Maluku Province.

The islands are mostly mountainous, and Tatamailau on Timor is the highest point at 2986 meters elevation. Wetar reaches 1,407 meters elevation.

Climate

The ecoregion has a tropical monsoon climate. The islands are in the rain shadow of Australia, and are among the driest in Indonesia. Rainfall is strongly seasonal, and April through November are generally the driest months. The windward southern side of the islands and receive annual rainfall of 2000 mm or more, with a two- to four-month dry season with less than 100 mm per month. The leeward north side of the island is much drier, receiving 1000 mm or less, with nine or more dry months. Some south-facing mountain areas above 900 meters elevation are humid year-round.[3][4]

Flora

Forest types include lowland evergreen rain forests, montane evergreen rain forests, semi-evergreen rain forests, moist deciduous forests, dry deciduous forests, and thorn forest/scrub. Evergreen and semi-evergreen rain forests occur in high-rainfall areas on the south side of the island. Deciduous forests and thorn forests are more widespread. Little primary forest remains; most forests are secondary. Extensive burning for shifting cultivation, grazing by goats and other livestock, and tree harvesting has reduced much of the island to anthropogenic grassland and scrub, including many invasive exotic shrubs.[5][6]

Savannas are common in the lowlands, and are of four types – palm savanna with Borassus flabellifer, eucalyptus savanna with Eucalyptus alba, acacia savanna, and casuarina savanna. Other plant communities include coastal dune grasslands and shrublands,[7]

Sandalwood (Santalum album) and candle nut (Aleurites moluccanus) are important tree crops harvested from the wild. Sandalwood was economically important, but over-harvesting has left it scarce and critically endangered.

Fauna

The ecoregion has thirty-eight mammal species.[8] The Timor shrew (Crocidura tenuis) and Timor rat (Rattus timorensis) are endemic. Two species were believed to have been brought to the islands long ago by humans – the Northern common cuscus (Phalanger orientalis), a marsupial originating in New Guinea, and the Javan rusa (Rusa timorensis), a deer originating in Java and Bali.[9][10]

The ecoregion is home to 229 bird species.[11] It corresponds to the Timor and Wetar endemic bird area. 23 species are endemic.[12]

Extinct fauna

Giant rats in the genus Coryphomys are believed to have gone extinct 1000–2000 years ago. Fossils of two species of Stegodon, an elephant relative, have been found on Timor, the most recent approximately 130,000 years old.[13] Mid-Pleistocene fossils of a giant monitor lizard, similar in size and related to the living Komodo dragon found on Flores and neighboring islands, have also been found on Timor.

Protected areas

A 2017 assessment found that 2,245 km², or 7%, of the ecoregion is in protected areas. About half the unprotected area is still forested.[14] Protected areas include Nino Konis Santana National Park (588.99 km²) and Kay Rala Xanana Gusmão National Park (92.31 km²) in East Timor.

  • "Timor and Wetar deciduous forests". Terrestrial Ecoregions. World Wildlife Fund.
  • Timor and Wetar endemic bird area (Birdlife International)

References
  1. Eric Dinerstein, David Olson, et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545; Supplemental material 2 table S1b.
  2. Wikramanayake, Eric; Eric Dinerstein; Colby J. Loucks; et al. (2002). Terrestrial Ecoregions of the Indo-Pacific: a Conservation Assessment. Washington, DC: Island Press.
  3. BirdLife International (2020) Endemic Bird Areas factsheet: Timor and Wetar. Downloaded from http://www.birdlife.org on 24/05/2020.
  4. Cowie, Ian (2006). "A Survey of Flora and Vegetation of the Proposed Jaco– Tutuala–Lore National Park, Timor-Leste (East Timor)". Birdlife International, May 2006.
  5. Cowie, Ian (2006). "A Survey of Flora and Vegetation of the Proposed Jaco– Tutuala–Lore National Park, Timor-Leste (East Timor)". Birdlife International, May 2006.
  6. Timor-Leste’s Fourth National Report to the UN Convention on Biological Diversity. National Biodiversity Working Group, Ministry of Economy and Development, Democratic Republic of Timor-Leste. October 2011.
  7. Wikramanayake, Eric; Eric Dinerstein; Colby J. Loucks; et al. (2002). Terrestrial Ecoregions of the Indo-Pacific: a Conservation Assessment. Washington, DC: Island Press.
  8. Wikramanayake, Eric; Eric Dinerstein; Colby J. Loucks; et al. (2002). Terrestrial Ecoregions of the Indo-Pacific: a Conservation Assessment. Washington, DC: Island Press.
  9. Grubb, P. (2005). "Rusa timorensis". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 670. ISBN 978-0-8018-8221-0. OCLC 62265494.
  10. Leary, T., Singadan, R., Menzies, J., Helgen, K., Wright, D., Allison, A., Hamilton, S., Salas, L. & Dickman, C. 2016. Phalanger orientalis. The IUCN Red List of Threatened Species 2016: e.T16847A21951519. https://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T16847A21951519.en. Downloaded on 21 May 2020.
  11. Wikramanayake, Eric; Eric Dinerstein; Colby J. Loucks; et al. (2002). Terrestrial Ecoregions of the Indo-Pacific: a Conservation Assessment. Washington, DC: Island Press.
  12. BirdLife International (2020) Endemic Bird Areas factsheet: Timor and Wetar. Downloaded from http://www.birdlife.org on 21/05/2020.
  13. Louys J, Price GJ, O’Connor S. 2016. Direct dating of Pleistocene stegodon from Timor Island, East Nusa Tenggara. PeerJ 4:e1788 https://doi.org/10.7717/peerj.1788
  14. Eric Dinerstein, David Olson, et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545; Supplemental material 2 table S1b.
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