Dr. Hayfaa Abdul Aziz publishes in NATURE

Munich research scientist Hayfaa Abdul Aziz and her co-authors have just published a paper on the astronomical forcing of mammal turnover.

Nature 443, 687-691(12 October 2006) | doi:10.1038/nature05163; Received 16 January 2006; Accepted 11 August 2006

Long-period astronomical forcing of mammal turnover

Jan A. van Dam1, Hayfaa Abdul Aziz1,6, M. Ángeles Álvarez Sierra2, Frederik J. Hilgen1, Lars W. van den Hoek Ostende3, Lucas J. Lourens1, Pierre Mein4, Albert J. van der Meulen1 and Pablo Pelaez-Campomanes5

Mammals are among the fastest-radiating groups, being characterized by a mean species lifespan of the order of 2.5 million years (Myr)1, 2. 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 turnover3, 4, but other studies have either challenged or only partly confirmed the climate–turnover hypothesis5, 6, 7. 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 oscillations8, 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.

1. Faculty of Geosciences, Department of Earth Sciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, The Netherlands
2. Faculty of Geology, Department of Paleontology, José Antonio Novais 2, Complutense University, Ciudad Universitaria, 28040 Madrid, Spain
3. National Museum of Natural History, Naturalis, Darwinweg 2, 2333 CR Leiden, The Netherlands
4. Faculty of Earth Sciences, University of Lyon I, 2 rue Dubois, 69622 Villeurbanne Cedex, France
5. National Museum of Natural History, CSIC, Department of Paleobiology, c/o José Gutiérrez Abascal 2, 28006 Madrid, Spain
6. †Present address: Department of Earth and Environmental Sciences, Geophysics LMU Munich, Theresienstraße 41, D-80333 Munich, Germany