van Dam Jan A, Abdul Aziz Hayfaa, Alvarez Sierra M Angeles, Hilgen Frederik J, van den Hoek Ostende Lars W, Lourens Lucas J, Mein Pierre, van der Meulen Albert J, Pelaez-Campomanes Pablo
Faculty of Geosciences, Department of Earth Sciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, The Netherlands.
Nature. 2006 Oct 12;443(7112):687-91. doi: 10.1038/nature05163.
Mammals are among the fastest-radiating groups, being characterized by a mean species lifespan of the order of 2.5 million years (Myr). The basis for this characteristic timescale of origination, extinction and turnover is not well understood. Various studies have invoked climate change to explain mammalian species turnover, but other studies have either challenged or only partly confirmed the climate-turnover hypothesis. Here we use an exceptionally long (24.5-2.5 Myr ago), dense, and well-dated terrestrial record of rodent lineages from central Spain, and show the existence of turnover cycles with periods of 2.4-2.5 and 1.0 Myr. We link these cycles to low-frequency modulations of Milankovitch oscillations, and show that pulses of turnover occur at minima of the 2.37-Myr eccentricity cycle and nodes of the 1.2-Myr obliquity cycle. Because obliquity nodes and eccentricity minima are associated with ice sheet expansion and cooling and affect regional precipitation, we infer that long-period astronomical climate forcing is a major determinant of species turnover in small mammals and probably other groups as well.
哺乳动物是辐射速度最快的类群之一，其特征是平均物种寿命约为250万年（Myr）。这种物种起源、灭绝和更替的特征时间尺度的基础尚未得到很好的理解。各种研究都援引气候变化来解释哺乳动物物种的更替，但其他研究要么对气候更替假说提出了质疑，要么只是部分证实了这一假说。在这里，我们利用了来自西班牙中部的一段异常漫长（距今2450万至250万年）、密集且年代测定良好的啮齿动物谱系陆地记录，并展示了存在周期为240万至250万年和100万年的更替周期。我们将这些周期与米兰科维奇振荡的低频调制联系起来，并表明更替脉冲出现在237万年偏心率周期的最小值和120万年倾角周期的节点处。由于倾角节点和偏心率最小值与冰盖扩张和冷却有关，并影响区域降水，我们推断长期的天文气候强迫是小型哺乳动物以及可能其他类群物种更替的主要决定因素。
