Extinction and replacement events shaped the historical biogeography of Arctic mammals in Europe: new models of species response

Abstract

1. The historical biogeography of the terrestrial mammals in Europe has been widely studied on the basis of fossil records and molecular makers. However, to date, only one model of species' responses to glacial–interglacial cycles during the glacial episodes of the Quaternary, especially during the Last Glacial Maximum, has been proposed: the ‘expansion-contraction model’.
2. The ‘expansion-contraction model’ is more appropriate for thermophilous and temperate species than for Arctic species. We hypothesise that the responses of cold-adapted species to the temperature fluctuations during glacial cycles cannot be explained by this model.
3. In this review, we synthesise and describe, for the first time, the historical biogeography of various cold-adapted terrestrial mammalian taxa (small mammals, herbivores, and carnivores) in Eurasia during the last glaciation (especially during the Last Glacial Maximum), and identify mechanisms underlying their response to glacier pulsation and severe climate fluctuations.
4. We formulate the paradigm for the biogeography of cold-adapted mammalian taxa in Europe, and identified three response models to glacial–interglacial cycles: 1) ‘extinction and genetic diminution’ for Lasiopodomys gregalis, Dicrostonyx spp. and Lemmus lemmus, 2) ‘extinction and replacement’ for Alopex lagopus, Gulo gulo and Rangifer tarandus, and 3) ‘contraction and gene transfer’ for Lepus timidus and Martes zibellina.
5. Knowledge of past biogeography is essential for understanding how cold-adapted taxa are responding to anthropogenic climate warming, and for on-going biodiversity and habitat conservation in the Anthropocene. There is no doubt that cold-adapted, Arctic species are suffering the most from global warming.