Department of Biological Sciences, Marshall University, Huntington, WV, USA.
La Brea Tar Pits and Museum, Natural History Museums of Los Angeles County, Los Angeles, CA, USA.
Science. 2023 Aug 18;381(6659):eabo3594. doi: 10.1126/science.abo3594.
The cause, or causes, of the Pleistocene megafaunal extinctions have been difficult to establish, in part because poor spatiotemporal resolution in the fossil record hinders alignment of species disappearances with archeological and environmental data. We obtained 172 new radiocarbon dates on megafauna from Rancho La Brea in California spanning 15.6 to 10.0 thousand calendar years before present (ka). Seven species of extinct megafauna disappeared by 12.9 ka, before the onset of the Younger Dryas. Comparison with high-resolution regional datasets revealed that these disappearances coincided with an ecological state shift that followed aridification and vegetation changes during the Bølling-Allerød (14.69 to 12.89 ka). Time-series modeling implicates large-scale fires as the primary cause of the extirpations, and the catalyst of this state shift may have been mounting human impacts in a drying, warming, and increasingly fire-prone ecosystem.
更新世巨型动物灭绝的原因一直难以确定，部分原因是化石记录的时空分辨率较差，难以将物种灭绝与考古和环境数据进行对齐。我们在加利福尼亚州的拉布雷亚农场获得了 172 个新的巨型动物放射性碳测年数据，时间跨度为距今 15600 年至 10000 年。到 12900 年前，即新仙女木事件之前，有 7 种已灭绝的巨型动物已经消失。与高分辨率区域数据集的比较表明，这些灭绝与干旱化和博林-阿勒罗德期（14690 年至 12890 年）植被变化之后的生态状态转变同时发生。时间序列模型表明，大规模火灾是灭绝的主要原因，而这种状态转变的催化剂可能是在一个干燥、变暖且越来越容易发生火灾的生态系统中，人类的影响不断增加。
