Climate change 'killed lemmings'
Published 26/11/2012 | 20:09
Lemmings in western Europe were killed off five times during the last Ice Age because of their inability to deal with rapid climate change, scientists have said.
Other small mammal species may have met a similar fate, experts believe.
The finding casts further doubt on claims that humans were largely to blame for the disappearance of large Ice Age animals such as the woolly mammoth, giant deer and cave bear.
It suggests that a series of short-lived warm periods led to inhospitable environments for many cold-adapted animals, leading to the collapse of local ecosystems.
Scientists analysed DNA from caves in Belgium and the UK to track the evolution of the collared lemming over a period of 50,000 years. Previously experts thought the lemming, and other small mammals, only vanished from more southern regions when the climate began to warm around 10,000 years ago.
"By focusing on a small mammal, we could remove the possibility that humans were having any significant impact on their population size - lemmings are just too numerous and prolific," said lead researcher Dr Ian Barnes, from Royal Holloway, University of London. "So any changes in the population had to be linked to wider environmental changes."
Colleague Dr Selina Brace, also from Royal Holloway, said: "While lemmings have an undeserved reputation for leaping off cliffs, in reality they are critical prey species for many arctic animals, and removing them from the ecosystem would have massive knock-on effects for predators."
The study, published in the journal Proceedings of the National Academy of Sciences, is one of the first to demonstrate that climatic change during the last Ice Age was an important driver of extinction.
During this period, lemmings in western Europe were wiped out five times. Each extinction was followed by a recolonisation of genetically different lemmings.
"That the lemmings in western Europe became extinct five times during the last Ice Age is unparalleled among mammals," said co-author Eleftheria Palkopoulou, from the Swedish Museum of Natural History. "We were really surprised by this finding."