sunda region

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Alfred Wallace identified the eastern border which is also the boundary of the Australasia and Indomalaya ecozones. (2010) analyzed stable carbon isotope composition in bat guano deposits in Sundaland and found strong evidence for the expansion of savanna in Sundaland. Mammal species of the world. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. [14] Selective pressure (in some cases resulting in extinction) has operated differently on each of the islands of Sundaland, and as a consequence, a different assemblage of mammals is found on each island. [3] An alternative theory points to the now-submerged Sundaland as the possible cradle of Asian population: thus the "Out of Sundaland" theory. [35] Later fauna included tigers, Sumatran rhinoceros, and Indian elephant, which were found throughout Sundaland; smaller animals were also able to disperse across the region.[7]. These islands have over 2,000 orchid species and hosts Rafflesia and Titan Arum which buds the largest flower on Earth. In total, Sundaland covers an area of about 694,983.88 miles squared in size. Ho… [28] There is also evidence for savanna vegetation, particularly in now submerged areas of Sundaland, throughout the last glacial period. Like elsewhere in the tropics, rainfall, rather than temperature, is the major determinant of regional variation. (2011) suggest that the sandy soils of the now submerged seabed are a more likely dispersal barrier. [4] During the Last Glacial Maximum sea level fell by approximately 120 meters, and the entire Sunda Shelf was exposed. [30] Morley and Flenley (1987) and Heaney (1991) were the first to postulate the existence of a continuous corridor of savanna vegetation through the center of Sundaland (from the modern Malaysian Peninsula to Borneo) during the last glacial period, based on palynological evidence. This ecoregion is situated in the middle of Borneo with parts of it in Indonesia, Brunei-owned territories, and Malaysia. Other than the Malay Peninsula and the islands of Sumatra, Borneo, and Java, Sundaland also includes part of the South China Sea, the Java Sea, and the Thailand Gulf. Biogeography and variation of. The most widespread glaciations in the ice age lasted for 21,000 years, and many scientists consider it to be the newest event of the bigger ice age which dates back to over 2 million years. Sarawak Museum Journal LX(81):191–284.

(2005) noted that although no single model predicts a continuous savanna corridor through Sundaland, many do predict open vegetation between modern Java and southern Borneo. The forest is home to some of the most distinct mammals including the orangutan, gibbons, Borneo round-leaf bat, and the endangered proboscis monkey. There are over 200 bird species in the jungle. The mammals of the Indomalayan region: a systematic review.

As a result, the modern islands of Sundaland are home to many Asian mammals including elephants, monkeys, apes, tigers, tapirs, and rhinoceros. [38] 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 that they were populated as late as 10,000 years ago from Taiwan. Other than the Malay Peninsula and the islands of Sumatra, Borneo, and Java, Sundaland also includes part of the South China Sea, the Java Sea, and the Thailand Gulf. 2005. Located in the subtropical and tropical moist broadleaf jungle biome, the swamp-forest is divided between three countries: Malaysia, Indonesia, and Brunei. Hall LS, Gordon G. Grigg, Craig Moritz, Besar Ketol, Isa Sait, Wahab Marni, Abdullah MT. The rivers in the region host some of the endangered small fishes such as the Parosphomenus. During the previous glacial maximum (the ice age), the sea level decreased by over 393.7 feet thus the whole Sunda shelf got exposed.

Today, the Sundaland hosts 25% of Earth’s fishes and 17% of Earth’s birds. The bigger portion of continental shelf got exposed from 110,000 to 12,000 years ago in the previous Glacial-period. 2004. [15] Island area and number of terrestrial mammal species are positively correlated, with the largest islands of Sundaland (Borneo and Sumatra) having the highest diversity. 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. However, this view is an extreme minority view among professional archaeologists, linguists, and geneticists. One example is the river threadfin (Polydactylus macrophthalmus, Bleeker 1858), which once thrived in a river system now called "North Sunda River" or "Molengraaff river". Biogeography of fruit bats in Southeast Asia. The term "Sundaland" was first proposed in 1949 by Van Bemmelen, followed by Katili in 1975, Hamilton in 1979, and finally Hutchison in 1989. The area of Sundaland encompasses the Sunda Shelf, a tectonically stable extension of Southeast Asia's continental shelf that was exposed during glacial periods of the last 2 million years. [9] The presence of fossil coral reefs dating to the late Miocene and early Pliocene suggests that, as the Indian monsoon grew more intense, seasonality increased in some portions of Sundaland during these epochs. [4] The northern border of Sundaland is more difficult to define in bathymetric terms; a phytogeographic transition at approximately 9ºN is considered to be the northern boundary. [18] Molengraaf also identified ancient, now submerged, drainage systems that drained the area during periods of lower sea level. The warm and shallow seas of the Sunda Shelf (averaging 28 °C or more) are part of the Indo-Pacific Warm Pool/Western Pacific Warm Pool[10] and an important driver of the Hadley circulation and the El Niño-Southern Oscillation (ENSO), particularly in January when it is a major heat source to the atmosphere.

[36], The population migrations were most likely to have been driven by climate change — the effects of the drowning of an ancient continent. Sundaland is in the tropics, and the equator passes through central Borneo and Sumatra. The name came from Sunda Kingdom, a kingdom ruling the west part of Java. Sumatra, Indonesian island, the second largest (after Borneo) of the Greater Sunda Islands, in the Malay Archipelago. Peat swamp forest forms when the water-logged soil stops the wood and dead leaves from decomposing entirely, resulting in the creation of a thick acidic peat layer. In total, Sundaland covers an area of about 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.

[3] The modern islands of Borneo, Java, and Sumatra have served as refugia for the flora and fauna of Sundaland during multiple glacial periods in the last million years, and are serving the same role at present. With the sea level dropping, numerous species like the dwarf elephantoid colonized this land. [4] 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 Indomalayan and Australasian realms. There are two opposing theories about the vegetation of Sundaland, particularly during the last glacial period: (1) that there was a continuous savanna corridor connecting modern mainland Asia to the islands of Java and Borneo, and (2) that the vegetation of Sundaland was instead dominated by tropical rainforest, with only small, discontinuous patches of savanna vegetation. The Sunda Strait is an important passage connecting the Indian Ocean with eastern Asia. Oppenheimer locates the origin of the Austronesians in Sundaland and its upper regions.

There are several volcanic islands within the strait, the most famous of which is Krakatoa, which erupted on August 27, 1883, causing a tsunami with waves as high as 125 feet (38 metres) that destroyed 300 towns and villages and killed about 36,000 people. [9] 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. [22], Sundaland, and in particular Borneo, has been an evolutionary hotspot for biodiversity since the early Miocene due to repeated immigration and vicariance events. The strait is also not correctly charted.

[9], During the last glacial period, sea levels were lower and all of Sundaland was an extension of the Asian continent. 80: 221–234. [2][3], The extent of the Sunda Shelf is approximately equal to the 120 meter isobath. Explorers and scientists began measuring and mapping the seas of Southeast Asia in the 1870s, primarily using depth sounding. Although the 17,000 islands of the Sundaland cover about 1% of the world’s land, this land mass hosts approximately 10% of the flowering species on Earth. [8] In contrast, sea level was higher during the late Pliocene, and the exposed area of Sundaland was smaller than what is observed at present. [15] However, the current species assemblage on each island is not simply a subset of a universal Sundaland or Asian fauna, as the species that inhabited Sundaland before flooding did not all have ranges encompassing the entire Sunda Shelf. It also comes from the name of the Sundanese people, the native people of West Java, with the Javanese people being found mostly in Central and East Java. The area of Sundaland encompasses the Sunda Shelf, a tectonically stable extension of Southeast Asia's continental shelf that was exposed during glacial periods of the last 2 million years.

The narrowest part of the Sunda Strait is located in the region between Cape Pujat and Cape Tua, on the islands of Java and Sumatra, respectively. The Most And Least Populated Provinces And Territories Of Canada? Of the three oceans that extend northward from the Antarctic continent, the…, Indian Ocean, body of salt water covering approximately one-fifth of the total ocean area of the world. [39][dubious – discuss]. The islands east of the Wallace line are known as Wallacea, a separate biogeographical region that is considered part of Australasia. [27], Dipterocarp trees characteristic of modern Southeast Asian tropical rainforest have been present in Sundaland since before the Last Glacial Maximum. There are several volcanic islands within the strait, the most famous of which is Krakatoa, which erupted on August 27, 1883, Updates? When the sea-level decreased by over 98.43 feet, the land bridges which connects the islands of Java, Borneo, and Sumatra to mainland Asia and the Malay Peninsula were exposed. Sunda Strait, Indonesian Selat Sunda, channel, 16–70 miles (26–110 km) wide, between the islands of Java (east) and Sumatra, that links the Java Sea (Pacific Ocean) with the Indian Ocean (south).

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