SYNERGISTIC ROLES OF CLIMATE WARMING AND HUMAN OCCUPATION IN PATAGONIAN MEGAFAUNAL EXTINCTIONS

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

Scientific Advances

Nature

Año: 2016 vol. 2 p. 1 - 8

The causes of Late Pleistocene megafaunal extinctions (60,000 to 11,650 years ago, hereafter 60 to 11.65 ka) remaincontentious, with major phases coinciding with both human arrival and climate change around the world. TheAmericas provide a unique opportunity to disentangle these factors as human colonization took place over anarrow timeframe (~15 to 14.6 ka) but during contrasting temperature trends across each continent. Unfortunately,limited data sets in South America have so far precluded detailed comparison. We analyze genetic and radiocarbondata from 89 and 71 Patagonian megafaunal bones, respectively, more than doubling the high-quality Pleistocenemegafaunal radiocarbon data sets from the region.Weidentify anarrowmegafaunal extinction phase 12,280 ± 110 yearsago, some 1 to 3 thousand years after initial human presence in the area. Although humans arrived immediatelyprior to a cold phase, the Antarctic Cold Reversal stadial, megafaunal extinctions did not occur until the stadialfinished and the subsequent warming phase commenced some 1 to 3 thousand years later. The increased resolutionprovided by the Patagonianmaterial reveals that the sequence of climate andextinctionevents inNorthandSouthAmerica were temporally inverted, but in both cases, megafaunal extinctions did not occur until human presence andclimate warming coincided. Overall, metapopulation processes involving subpopulation connectivity on a continentalscale appear to have been critical for megafaunal species survival of both climate change and human impacts.