Synergistic roles of climate warming and human occupation in Patagonian megafaunal extinctions during the Last Deglaciation

BARNETT, ROSS; VILSTRUP, JULIA; TURNEY, CHRIS; LOPONTE, DARÍO; BRAY, SARAH; CIVALERO, TERESA; SALAS-GISMONDI, RODOLF; DURAN VICTOR; DE NIGRIS, MARIANA; GIL, ADOLFO; GASCO, ALEJANDRA; BRADSHAW, COREY; OTAOLA, CLARA; AUSTIN, JEREMY; PREVOSTI, FRANCISCO; METCALF, JESSICA; BORRERO, LUIS; MARTIN, FABIANE; ORLANDO, LUDOVICO; MEDINA, MATÍAS; FERNÁNDEZ, PABLO; SEYMOUR, LEVIN; PAUNERO, RAFAEL; WHEELER, JANE; COOPER, ALAN

Science Advances

Science

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

2375-2548

The causes of Late Pleistocene megafaunal extinctions (60,000 to 11,650years ago, hereafter 60 to 11.65 ka) remaincontentious, with major phasescoinciding with both human arrival and climate change around the world. The Americasprovide a unique opportunity to disentangle these factors as human colonizationtook place over a narrow time frame (~15 to 14.6 ka) but during contrastingtemperature trends across each continent. Unfortunately, limited data sets inSouth America have so far precluded detailed comparison. We analyze genetic andradiocarbon data from 89 and 71 Patagonian megafaunal bones, respectively, morethan doubling the high-quality Pleistocene megafaunal radiocarbon data setsfrom the region. We identify a narrow megafaunal extinction phase 12,280 ± 110years ago, some 1 to 3 thousand years after initial human presence in the area.Although humans arrived immediately prior to a cold phase, the Antarctic ColdReversal stadial, megafaunal extinctions did not occur until the stadial finishedand the subsequent warming phase commenced some 1 to 3 thousand years later.The increased resolution provided by the Patagonian material reveals that thesequence of climate and extinction events in North and South America were temporallyinverted, but in both cases, megafaunal extinctions did not occur until humanpresence and climate warming coincided. Overall, metapopulation processesinvolving subpopulation connectivity on a continental scale appear to have beencritical for megafaunal species survival of both climate change and humanimpacts.