 A savannah in Middle Pleistocene Southeast Asia. foreground: stegodon, hyenas, and Asian rhinos (Rhinoceros). background: water buffalo can be seen at the edge of a riparian forest |
in Louys & Roberts, 2020. Illustration: Peter Schouten |
Abstract
Southeast Asia has emerged as an important region for understanding hominin and mammalian migrations and extinctions. High-profile discoveries have shown that Southeast Asia has been home to at least five members of the genus Homo. Considerable turnover in Pleistocene megafauna has previously been linked with these hominins or with climate change, although the region is often left out of discussions of megafauna extinctions. In the traditional hominin evolutionary core of Africa, attempts to establish the environmental context of hominin evolution and its association with faunal changes have long been informed by stable isotope methodologies. However, such studies have largely been neglected in Southeast Asia. Here we present a large-scale dataset of stable isotope data for Southeast Asian mammals that spans the Quaternary period. Our results demonstrate that the forests of the Early Pleistocene had given way to savannahs by the Middle Pleistocene, which led to the spread of grazers and extinction of browsers—although geochronological limitations mean that not all samples can be resolved to glacial or interglacial periods. Savannahs retreated by the Late Pleistocene and had completely disappeared by the Holocene epoch, when they were replaced by highly stratified closed-canopy rainforest. This resulted in the ascendency of rainforest-adapted species as well as Homo sapiens—which has a unique adaptive plasticity among hominins—at the expense of savannah and woodland specialists, including Homo erectus. At present, megafauna are restricted to rainforests and are severely threatened by anthropogenic deforestation.
Biogeography, Biological anthropology, Ecosystem ecology, Environmental impact, Palaeontology
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| Artist’s reconstruction of a savannah in Middle Pleistocene Southeast Asia. In the foreground Homo erectus, stegodon, hyenas, and Asian rhinos are depicted. Water buffalo can be seen at the edge of a riparian forest in the background. Illustration: Peter Schouten |
Julien Louys and Patrick Roberts. 2020. Environmental drivers of megafauna and hominin extinction in Southeast Asia. Nature. DOI: 10.1038/s41586-020-2810-y
Past Tropical Forest Changes Drove Megafauna and Hominin Extinctions
New biochemical research shows significant turnovers in Southeast Asian environments and animals during the Pleistocene
