Synergistic roles of climate warming and human occupation in Patagonian megafaunal extinctions

CHRIS TURNEY; SARAH C. BRAY; RODOLFO SALAS-GISMONDI; MARIANA DE NIGRIS; ALEJANDRA GASCO; CLARA OTAOLA; FRANCISCO PREVOSTI; LUIS BORRERO; ROSS BARNETT; JULIA T. VILSTRUP; METCALF, J.; DANIEL LOPONTE; FABIANA MARTIN; TERESA CIVALERO; VICTOR DURAN; LUDOVIC ORLANDO; ADOLFO GIL; MATÍAS MEDINA; PABLO MARCELO FERNÁNDEZ; COREY BRADSHAW; KEVIN L. SEYMOUR; JEREMY J. AUSTIN; RAFAEL PAUNERO; JANE WHEELER; ALAN COOPER

Sciences Advances

AAAS

Año: 2016 vol. 2016 p. 1 - 10

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 world. The Americas provide a unique opportunity to disentangle these factors as human colonization took place over a narrow timeframe (~15-14.6 kyr), but during contrasting temperature trends across each continent. Unfortunately, limited datasets in South America have so far precluded detailed comparison. Here we analyse genetic and radiocarbon data from 90 and 71 Patagonian megafaunal bones, respectively, more than doubling the high-quality Pleistocene megafaunal radiocarbon datasets from the region. We identify a narrow megafaunal extinction phase 12,280±110 years ago, some 1-3 kyr after initial human presence in the area. While humans arrived immediately prior to the cold phase of the Antarctic Cold Reversal stadial, megafaunal extinctions did not occur until the stadial finished and the subsequent warming phase commenced some 1-3 kyr later. The increased resolution provided by the Patagonian material reveals that the sequence of climate and extinction events in North and South America were temporally inverted, butin both cases megafaunal extinctions did not occur until human presence and climatic warming coincided. Overall, 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.