Sundaland

For other uses, see Sunderland (disambiguation).
"Sundas" redirects here. For the Greater Sundas, see Greater Sunda Islands. For the Lesser Sundas, see Lesser Sunda Islands.
The Sahul Shelf and the Sunda Shelf today. The area in between is called "Wallacea".

Sundaland (also called the Sundaic region) is a biogeographical region of Southeastern Asia which encompasses the Sunda shelf, the part of the Asian continental shelf that was exposed during the last glacial period of the Pleistocene, from approximately 110,000 to 12,000 years ago. It includes the Malay Peninsula Malaysia on the Asian mainland, as well as the large islands of Borneo, Java, and Sumatra and their surrounding islands.

The eastern boundary of Sundaland is the Wallace Line, identified by Alfred Russel Wallace as the eastern boundary of the range of Asia's land mammal fauna, and thus the boundary of the Indomalaya and Australasia ecozones. The islands east of the Wallace line are known as Wallacea, and are considered part of Australasia.

History

The South China Sea and adjoining landmasses had been investigated by scientists such as Molengraaff and Umbgrove, who had postulated ancient, now submerged, drainage systems. These were mapped by Tjia in 1980 and described in greater detail by Emmel and Curray in 1982 complete with river deltas, floodplains and backswamps.[1] The ecology of the exposed Sunda shelf has been investigated by analyzing cores drilled into the ocean bed. The pollens found in the cores have revealed a complex ecosystem that changed over time.[2]

The flooding of Sundaland separated species that had once shared the same environment such as the river threadfin (Polydactylus macrophthalmus, Bleeker 1858), that had once thrived in a river system now called "North Sunda River" or "Molengraaff river". The fish is now found in the Kapuas River on the island of Borneo, and in the Musi and Batanghari rivers in Sumatra.[3]

Human migrations

According to the most widely accepted theory, the ancestors of the modern-day Austronesian populations of the Malay archipelago and adjacent regions are believed to have migrated southward, from the East Asia mainland to Taiwan, and then to the rest of Maritime Southeast Asia. An alternative theory points to the now-submerged Sundaland as the possible cradle of Asian population: thus the "Out of Sundaland" theory. However, this view is an extreme minority view among professional archaeologists, linguists, and geneticists. The Out of Taiwan model (though not necessarily the Express Train Out of Taiwan model) is accepted by the vast majority of professional researchers.

A study from Leeds University and published in Molecular Biology and Evolution, examining mitochondrial DNA lineages, suggested that humans had been occupying the islands of Southeast Asia for a longer period than previously believed. Population dispersals seem to have occurred at the same time as sea levels rose, which may have resulted in migrations from the Philippine Islands to as far north as Taiwan within the last 10,000 years.[4]

The population migrations were most likely to have been driven by climate change — the effects of the drowning of an ancient continent. Rising sea levels in three massive pulses may have caused flooding and the submerging of the Sunda continent, creating the Java and South China Seas and the thousands of islands that make up Indonesia and the Philippines today. The changing sea levels would have caused these humans to move away from their coastal homes and culture, and farther inland throughout southeast Asia. This forced migration would have caused these humans to adapt to the new forest and mountainous environments, developing farms and domestication, and becoming the predecessors to future human populations in these regions.[5]

A 2009 genetic study published by the 2009 Human Genome Organization Pan-Asian SNP Consortium found that Asia was originally settled by humans via a single southern route. The migration came from Africa via India, into Southeast Asia and what are now islands in the Pacific, and then later up to the eastern and northern Asian mainland.[6]

Genetic similarities were found between populations throughout Asia and an increase in genetic diversity from northern to southern latitudes. Although the Chinese population is very large, it has less variation than the smaller number of individuals living in Southeast Asia, because the Chinese expansion occurred very recently, within only the last 2,000 to 3,000 years, following the perfection of rice agriculture.

Oppenheimer locates the origin of the Austronesians in Sundaland and its upper regions.[7] Genetic research reported in 2008 indicates that the islands which are the remnants of Sundaland were likely populated as early as 50,000 years ago, contrary to a previous hypothesis {Bellwood and Dizon 2005} that they were populated as late as 10,000 years ago from Taiwan.[8]

From the standpoint of historical linguistics, the home of the Austronesian languages is the main island of Taiwan, formerly known as Formosa; on this island the deepest divisions in Austronesian are found, among the families of the native Formosan languages.

Ecology

The islands of Sundaland rest on an extension of Asia's shallow continental shelf, called the Sunda shelf. During the ice ages, sea levels were lower and all of Sundaland was an extension of the Asian continent.

As a result, the islands of Sundaland are home to many Asian mammals including elephants, monkeys, apes, tigers, tapirs, and rhinoceros. The Wallace Line, which includes the Lombok Strait between Bali and Lombok, and the Makassar Strait between Borneo and Sulawesi, marks the end of the Asian continental shelf. The islands of Wallacea are separated from Asia and from Australia and New Guinea by deep ocean.

Botanists often include Sundaland, the adjacent Philippines, Wallacea and New Guinea in a single Floristic province of Malesia, based on similarities in their flora, which is predominantly of Asian origin.

Ecoregions of Sundaland

Tropical and subtropical moist broadleaf forests

Tropical and subtropical coniferous forests

Montane grasslands and shrublands

Mangroves

See also

References

Citations

  1. ↑ The physical geography of Southeast Asia by Avijit Gupta, 2005, ISBN 0-19-924802-8 , page 403
  2. ↑ Till Hanebuth, Karl Stattegger and Pieter M. Grootes, "Rapid Flooding of the Sunda Shelf: A Late-Glacial Sea-Level Record", Science 288 12 May 2000:1033–35.
  3. ↑ Distributation of the River Threadfin
  4. ↑ Dr. Martin Richards. "Climate Change and Postglacial Human Dispersals in Southeast Asia". Oxford Journals. Retrieved 2010. Check date values in: |access-date= (help)
  5. ↑ Higham, C. F. W., Guangmao, X., & Qiang, L. (2011). The prehistory of a Friction Zone: first farmers and hunters-gatherers in Southeast Asia. Antiquity,85(328).
  6. ↑ Press release: Agency for Science, Technology and Research (A*STAR), Singapore (2009-12-10). "Genetic ancestry highly correlated with ethnic and linguistic groups in Asia". Retrieved 2012-06-14.
    Paper: The HUGO Pan-Asian SNP Consortium (2009-12-11). "Mapping Human Genetic Diversity in Asia". Science. 326 (5959): 1541–1545. doi:10.1126/science.1177074. PMID 20007900.
  7. ↑ Oppenheimer 1999
  8. ↑ New research forces U-turn in population migration theory

Sources

Selected faunal references in Borneo

Further reading

This article is issued from Wikipedia - version of the 11/2/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.