Synergistic Roles of Climate Warming and Human Occupation in Patagonian Megafaunal Extinctions

METCALF, J.; TURNEY, C.; BARNETT, R.; MARTIN, F.; BRAY, S.; VILSTRUP, J.; ORLANDO, L.; SALAS-GISMONDI, R.; LOPONTE, D.; MEDINA, M.; DE NIGRIS, M.; CIVALERO, T.; FERNÁNDEZ; P.; GASCO, A.; DURAN, V.; SEYMOUR, K.; OTAOLA, C.; GIL, A.; PAUNERO, R.; PREVOSTI, F.; BRADSHAW, C.; WHEELER, J.; BORRERO, L.; AUSTIN, J.; COOPER, A.

science advances

American Association for the Advancement of Science, Washington

Lugar: Washington; Año: 2016 vol. 2 p. 1 - 8

The causes of Late Pleistocene megafaunal extinctions (60,000 to 11,650 years ago, hereafter 60-11.65 kyr) remain contentious, with major phases coinciding with both human arrival and climate change around the world1,2. The Americas provides a unique opportunity to disentangle these factors as human colonization took place over a narrow time frame (~15-14.6kyr) during contrasting temperature trends across each continent. Unfortunately, limited datasets in South America have precluded detailed comparison4. Here we analyse genetic and radiocarbon data from 90 Patagonian megafaunal bones, more than doubling the number of species and radiocarbon datasets from the region. We identify a narrow megafaunal extinction phase 12,280±110 years ago. Although humans were present1-3 kyr earlier, immediately prior to the Antarctic Cold Reversal stadial, megafaunal extinctions did not occur until the subsequent warming phase commenced. We find the sequence of events in North and South America were out of phase temporally, but in both cases extinctions occurred when human presence and climatic warming coincided. Metapopulation processes involving subpopulation connectivity on a continental scale appear to have been critical for megafaunal species survival of both climate change and human impacts.