Sundaland
It includes Bali, Borneo, Java, and Sumatra in Indonesia, and their surrounding small islands, as well as the Malay Peninsula on the Asian mainland.
[3] The western and southern borders of Sundaland are clearly marked by the deeper waters of the Sunda Trench – some of the deepest in the world – and the Indian Ocean.
[7][6] When the sea level was decreased by 30–40 meters or more, land bridges connected the islands of Borneo, Java, and Sumatra to the Malay Peninsula and mainland Asia.
[2] Because the sea level was 30 meters or more lower throughout much of the last 800,000 years, the current status of Borneo, Java, and Sumatra as islands has been a relatively rare occurrence throughout the Pleistocene.
Most of Sundaland is classified as perhumid, or everwet, with over 2,000 millimeters of rain annually;[4] rainfall exceeds evapotranspiration throughout the year and there are no predictable dry seasons like elsewhere in Southeast Asia.
[11] 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.
As a result, the modern islands of Sundaland are home to many Asian mammals including elephants, monkeys, apes, tigers, tapirs, and rhinoceros.
[18] In an 1852 publication, English navigator George Windsor Earl advanced the idea of a "Great Asiatic Bank", based in part on common features of mammals found in Java, Borneo and Sumatra.
The name "Sundaland" for the peninsular shelf was first proposed by Reinout Willem van Bemmelen in his Geography of Indonesia in 1949, based on his research during World War II.
The ancient drainage systems described by Molengraaff were verified and mapped by Tjia in 1980[21] and described in greater detail by Emmel and Curray in 1982 complete with river deltas, floodplains and backswamps.
[11] 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.
Some authors argue that rainfall decreased with the area of ocean available for evaporation as sea levels fell with ice sheet expansion.
[32] 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 Malay Peninsula to Borneo) during the last glacial period, based on palynological evidence.
[4] And in contrast to previous findings, Wurster et al. (2017) again used stable carbon isotope analysis of bat guano, but found that at some sites rainforest cover was maintained through much of the last glacial period.
[38] Later fauna included tigers, Sumatran rhinoceros, and Indian elephant, which were found throughout Sundaland; smaller animals were also able to disperse across the region.
[citation needed] A study from Leeds University and published in Molecular Biology and Evolution, examining mitochondrial DNA lineages, suggested that shared ancestry between Taiwan and Southeast Asian resulted from earlier migrations.
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.
The changing sea levels would have caused these humans to move away from their coastal homes and culture, and farther inland throughout southeast Asia.
