Lesser Sunda Islands

Lesser Sunda Islands
Native name:
Kepulauan Nusa Tenggara
Kepulauan Sunda Kecil
Lesser Sunda Islands en.png
Geography
Location Southeast Asia
Southwestern Pacific
Coordinates 9°00′S 120°00′E / 9.000°S 120.000°E / -9.000; 120.000
Archipelago Sunda Islands
Highest elevation 3,726 m (12224 ft)
Administration
Provinces Bali
West Nusa Tenggara
East Nusa Tenggara
Maluku (Barat Daya Islands and Tanimbar Islands only)
Municipalities Oecusse
Liquiçá
Dili
Manatuto
Baucau
Lautém
Bobonaro
Ermera
Aileu
Viqueque
Cova Lima
Ainaro
Manufahi
Demographics
Ethnic groups Balinese, Sasak, Bimese, Atoni, Manggaraian, Sumbawan, Dompuan, Sumbese, Lamaholot, Tetum, Mambai, Kemak, Moluccans, Alfur, Javanese, Bugis
Map of Lesser Sunda Islands
Satellite picture of the Lesser Sunda Islands
Banta Island of Lesser Sunda Islands

The Lesser Sunda Islands (Indonesian: Kepulauan Nusa Tenggara "southeastern archipelago" or Kepulauan Sunda Kecil "lesser sunda archipelago"[1]) are an archipelago in Maritime Southeast Asia, north of Australia. Together with the Greater Sunda Islands to the west they make up the Sunda Islands. The islands are part of a volcanic arc, the Sunda Arc, formed by subduction along the Sunda Trench in the Java Sea.

The main Lesser Sunda Islands are, from west to east: Bali, Lombok, Sumbawa, Flores, Sumba, Timor, Alor archipelago, Barat Daya Islands, and Tanimbar Islands.

Administration

The Lesser Sundas comprise many islands, most of which are part of Indonesia and are administered as the provinces of Bali, West Nusa Tenggara, East Nusa Tenggara and the southern part of Maluku.

The eastern half of Timor is the separate nation of East Timor.

Geology

The Lesser Sunda Islands consist of two geologically distinct archipelagos.[2] The northern archipelago, which includes Bali, Lombok, Sumbawa, Flores and Wetar, is volcanic in origin. A number of these volcanoes, like Mount Rinjani on Lombok, are still active while others, such as Ilikedeka on Flores, are extinct. The northern archipelago began to be formed during the Pliocene, about 15 million years ago, as a result of the collision between the Australian and the Asian plates.[2] The islands of the southern archipelago, including Sumba, Timor and Babar, are non-volcanic and appear to belong to the Australian plate.[3] The geology and ecology of the northern archipelago share similar history, characteristics, and processes with the southern Maluku Islands, which continue the same island arc to the east.

There is a long history of geological study of these regions since Indonesian colonial times; however, the geological formation and progression is not fully understood, and theories of the geological evolution of the islands changed extensively during the last decades of the 20th century.[4]

Lying at the collision of two tectonic plates, the Lesser Sunda Islands comprise some of the most geologically complex and active regions in the world.[4]

There are a number of volcanoes located on the Lesser Sunda Islands.[5]

Ecology

The Lesser Sunda Islands differ from the large islands of Java or Sumatra in consisting of many small islands, sometimes divided by deep oceanic trenches. Movement of flora and fauna between islands is limited, leading to the evolution of a high rate of localized species, most famously the Komodo dragon.[4] As described by Alfred Wallace in The Malay Archipelago, the Wallace Line passes between Bali and Lombok, along the deep waters of the Lombok Strait which formed a water barrier even when lower sea levels linked the now-separated islands and landmasses on either side. The islands east of the Lombok Strait are part of Wallacea, and are thus characterised by a blend of wildlife of Asian and Australasian origin in this region.[6] Asian species predominate in the Lesser Sundas: Weber's Line, which marks the boundary between the parts of Wallacea with mainly Asian and Australasian species respectively, runs to the east of the group. These islands have the driest climate in Indonesia, and tropical dry broadleaf forests are predominant, in contrast to the tropical moist forests that prevail in most of Indonesia.

Ecoregions

The Lesser Sunda Islands are divided among six ecoregions:[7]

Threats and preservation

Rinca island
Komodo dragon at Komodo National Park

More than half of the original vegetation of the islands has been cleared for planting of rice and other crops, for settlement and by consequent forest fires. Only Sumbawa now contains a large area of intact natural forest, while Komodo, Rincah and Padar are now protected as Komodo National Park.

While many ecological problems affect both small islands and large landmasses, small islands suffer their particular problems and are highly exposed to external forces. Development pressures on small islands are increasing, although their effects are not always anticipated. Although Indonesia is richly endowed with natural resources, the resources of the small islands of Nusa Tenggara are limited and specialised; furthermore human resources in particular are limited.[8]

General observations[9] about small islands that can be applied to Nusa Tenggara include:[8]

  • A higher proportion of the landmass will be affected by volcanic activity, earthquakes, landslips, and cyclone damage;
  • Climates are more likely to be maritime influenced;
  • Catchment areas are smaller and degree of erosion higher;
  • A higher proportion of the landmass is made up of coastal areas;
  • A higher degree of environmental specialisation, including a higher proportion of endemic species in an overall Depauperate community;
  • Societies may retain a strong sense of culture having developed in relative isolation;
  • Small island populations are more likely to be affected by economic migration.

See also

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