Global warming may threaten the survival of European lizards by forcing the reptiles to live fast and die young, new research has shown.
Scientists set up an experiment in which 18 populations of common lizards lived in semi-natural enclosures, one of which simulated an end-of-the-century climate 2˚C warmer than it is today.
After a year, lizards in the warmer conditions were found to be coping very badly and dying at a rate that would lead to rapid population extinctions in around 20 years.
Elvire Bestion, from the University of Exeter, who co-led the study, said: “While a two-degrees warmer climate might seem beneficial at first, as it leads to faster growth of juvenile lizards and earlier access to reproduction, it also leads to lower survival in adult individuals, which should endanger population survival.”
The common, or viviparous lizard, Zootoca vivipara, is widespread across Europe and one of only two indigenous lizards in the UK, not including the legless slow worm.
Co-author Julien Cote, from the Laboratoire Evolution et Diversite Biologique in France, said the team did not predict the total extinction of the common lizard. But he added that some populations could be hit hard by climate change.
While a two-degrees warmer climate might seem beneficial at first, it leads to lower survival in adult individuals
“We suggest that populations at the southern edge of their range of distribution might particularly suffer from warmer climates,” he said. Across Europe as a whole, between 14 per cent and 30 per cent of lizard populations could be threatened.
Bestion said: “Anecdotally, we showed that warmer climates led some adult females to engage into a second reproduction event during the summer, while these lizards normally reproduce only once a year during the spring.
“Combined with the earlier juvenile reproduction and the higher adult survival, these results suggest a shift of demographic strategy from a relatively long life and low reproductive output to a faster life, higher reproductive investment. We can wonder whether this strategy shift may help adaptation of populations to warmer climates over time.”
The research is published in the journal Public Library of Science Biology.