Data from: Spatially explicit analysis sheds new light on the Pleistocene megafaunal extinction in North America

The late Pleistocene megafaunal extinctions may have been the first extinctions directly related to human activity, but in North America the close temporal proximity of human arrival and the Younger Dryas climate event has hindered efforts to identify the ultimate extinction cause. Previous work evaluating the roles of climate change and human activity in the North American megafaunal extinction has been stymied by a reliance on geographic binning, yielding contradictory results among researchers. We used a fine-scale geospatial approach in combination with 95 megafaunal last-appearance and 75 human first-appearance radiocarbon dates to evaluate the North American megafaunal extinction. We used kriging to create interpolated first- and last-appearance surfaces from calibrated radiocarbon dates in combination with their geographic autocorrelation. We found substantial evidence for overlap between megafauna and human populations in many but not all areas, in some cases exceeding 3,000 years of predicted overlap. We also found that overlap was highly regional; megafauna had last appearances in Alaska before humans first appeared, but did not have last appearances in the Great Lakes region until several thousand years after the first recorded human appearances. Overlap in the Great Lakes region exceeds uncertainty in radiocarbon measurements or methodological uncertainty, and would be even greater with sampling-derived confidence intervals. The kriged maps of last megafaunal occurrence are consistent with climate as a primary driver in some areas, but we cannot eliminate human influence from all regions. The late Pleistocene megafaunal extinction was highly variable in timing and duration of human overlap across the continent, and future analyses should take these regional trends into account.

晚更新世（late Pleistocene）巨型动物群灭绝事件，或许是首批直接与人类活动相关的物种灭绝事件，但在北美地区，人类抵达与新仙女木（Younger Dryas）气候事件的时间间隔极近，这一情况阻碍了学界确定该次灭绝最终诱因的研究。过往针对北美巨型动物群灭绝事件中气候变化与人类活动所扮演角色的研究，因依赖地理分区法（geographic binning）而受阻，不同研究者间得出了相互矛盾的结论。本研究采用高精度地理空间分析方法，结合95组巨型动物群末次出现（last-appearance）与75组人类首次出现（first-appearance）的放射性碳定年数据，对北美巨型动物群灭绝事件展开评估。研究通过克里金插值法（kriging），结合经校准的放射性碳定年数据及其地理自相关（geographic autocorrelation）特征，构建了首次出现与末次出现的空间插值表面。研究发现，在多数（而非全部）区域中，巨型动物群与人类种群存在显著的共存证据，部分区域的预测共存时长甚至超过3000年。同时研究还发现，共存情况具有极强的区域性：阿拉斯加地区的巨型动物群末次出现时间早于人类首次抵达时间，而五大湖区域的巨型动物群末次出现时间，则晚于有记录的人类首次抵达时间数千年。五大湖区域的共存时长超出了放射性碳测量误差与方法学误差的范围，若考虑抽样带来的置信区间，这一差值还会进一步扩大。经克里金插值得到的巨型动物群末次出现分布图，与部分区域以气候为主要驱动因素的推论相符，但我们无法排除所有区域中人类活动的影响。晚更新世巨型动物群灭绝事件中，人类与巨型动物群的共存时间与持续时长在北美大陆上存在显著差异，未来的相关分析应将这些区域性趋势纳入考量。