Tuesday, December 11, 2012

Do Serial Small Mammal Extinctions Indicate th 6th Mass Extinction Was Climate Driven?

Serial population extinctions in a small mammal indicate Late Pleistocene ecosystem instability


1. Selina Brace (a)
2. Eleftheria Palkopoulou (b,c)
3. Love Dalén (b)
4. Adrian M. Lister (d)
5. Rebecca Miller (e)
6. Marcel Otte (e)
7. Mietje Germonpré (f)
8. Simon P. E. Blockley (g)
9. John R. Stewart (h)
10. Ian Barnes (a,*)

*. To whom correspondence should be addressed. E-mail: ian.barnes@rhul.ac.uk.


a. School of Biological Sciences Royal Holloway University of London, Egham, Surrey TW20 0EX, United Kingdom

b. Department of Molecular Systematics, Swedish Museum of Natural History, 104 05 Stockholm, Sweden

c. Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden

d. Department of Earth Sciences, Natural History Museum, London SW7 5BD, United Kingdom

e. Service of Prehistory, University of Liège, 4000 Liège, Belgium

f. Department of Palaeontology, Royal Belgian Institute of Natural Sciences, 1000 Brussels, Belgium

g. Department of Geography Sciences Royal Holloway University of London, Egham, Surrey TW20 0EX, United Kingdom

h. School of Applied Sciences, Bournemouth University, Poole, Dorset BH12 5BB, United Kingdom


The Late Pleistocene global extinction of many terrestrial mammal species has been a subject of intensive scientific study for over a century, yet the relative contributions of environmental changes and the global expansion of humans remain unresolved. A defining component of these extinctions is a bias toward large species, with the majority of small-mammal taxa apparently surviving into the present. Here, we investigate the population-level history of a key tundra-specialist small mammal, the collared lemming (Dicrostonyx torquatus), to explore whether events during the Late Pleistocene had a discernible effect beyond the large mammal fauna. Using ancient DNA techniques to sample across three sites in North-West Europe, we observe a dramatic reduction in genetic diversity in this species over the last 50,000 y. We further identify a series of extinction-recolonization events, indicating a previously unrecognized instability in Late Pleistocene small-mammal populations, which we link with climatic fluctuations. Our results reveal climate-associated, repeated regional extinctions in a keystone prey species across the Late Pleistocene, a pattern likely to have had an impact on the wider steppe-tundra community, and one that is concordant with environmental change as a major force in structuring Late Pleistocene biodiversity.

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