Lizards facing mass extinction from climate change: study

Climate change could see dozens of lizard species becoming extinct within the next 50 years, a new research has warned.
Globally it has been observed that lizards with viviparous reproduction (retention of embryos within the mother's body) are being threatened by changing weather patterns.
The new study led by University of Lincoln suggested that the evolution of this mode of reproduction, which is thought to be a key successful adaptation, could, in fact, be the species' downfall under global warming.
Researchers investigated the hypothesis that historical invasions of cold climates by Liolaemus lizards - one of the most diverse groups of vertebrates on earth - have only been possible due to their evolution to viviparity (live birth) from oviparity (laying eggs).

Remarkably, once these species evolve viviparity, the process is mostly irreversible and they remain restricted to such cold climates.
By analysing this evolutionary transition in the lizards' reproductive modes and projecting the future impact of climate change, the scientists found that increasing temperatures in the species' historically cold habitats would result in their areas of distribution being significantly reduced.

"Lizards' reproduction is largely linked to climatic temperatures and viviparous species are usually found in cold environments," said Daniel Pincheira-Donoso from the University of Lincoln and lead author of the paper published in journal Global Ecology and Biogeography.
"When reptiles initially moved to colder areas they needed to evolve emergency measures to succeed in these harsh places, and we believe viviparity is one of these key measures. However, this transition is mostly one-directional and unlikely to be reversed," he said in a statement.

"Rapid changes in the environment's temperature would demand rapid re-adaptations to secure the species' survival. Through the research we found that over the next 50 years nearly half of the area where these species occur may disappear, causing multiple extinctions due to climate change," he added.
The study concluded that although viviparity allowed lizards in the past to invade and adapt to live in cold environments, and was therefore a key trait for evolutionary success, it will now ultimately lead to multiple events of extinction.
"Our work shows that lizard species which birth live young instead of laying eggs are restricted to cold climates in South America: high in the Andes or towards the South Pole," researcher Dr Dave Hodgson, from the University of Exeter, said.

"As the climate warms, we predict that these special lizard species will be forced to move upwards and towards the pole, with an increased risk of extinction," Hodgson said.