Rapid climate change during last Ice Age found to be cause

A new study has revealed that during the last Ice Age lemmings became “regionally extinct” five times. Scientists also found that each extinction was due to rapid climate change.

The study investigated how Europe’s small mammals fared during the era when large numbers of megafauna became extinct.

Experts believed that small mammals were largely unaffected, however, an international research team were surprised by the results, when they analysed ancient DNA sequences from cave site remains of collared lemmings, found fossilised in Belgium.

Research team member Dr Ian Barnes, from the school of biological sciences at Royal Holloway University in Surrey, said: “What we'd expected is that there'd be pretty much just a single population that was there all the way through.

Instead the tests revealed that genetically distinct populations of lemmings were "present at different points in time" during the Late Pleistocene -around 11,700 to 126,000 years ago.

This finding show that the lemming population had been wiped out multiple times - causing "regional extinctions - and then re-colonised some time after, possibly from populations in eastern Europe or Russia.

The extinctions occurred during periods of rapid warming that suggests temperature fluxuations may have left lemmings unable to adapt to the changes in the vegetation they relied on as a food source.

Although Belgium's lemmings were able to re-colonise after each regional extinction, the population lost much of its genetic diversity during this pattern of events.

The team's findings could also shed light on why many of Europe's megafauna, such as woolly mammoths, cave hyenas and cave bears, became extinct during the same period.

According to the study, this pattern supports the theory that environmental changes, rather than human predation, were the main cause of the demise of megafauna in Europe at the end of the last Ice Age.