A new study published in Nature has examined how the increase in global temperatures has already impacted amphibians – and the potential impact should the temperature consider to rise.
The study found that just over 100 out of the 5,203 amphibian species analysed are already exposed to overheating events. And if global temperatures continue to rise by 4C, nearly 400 species – at a minimum – will be pushed to their limits.
This estimate includes access to shade and water, as habitat loss, drought and disease will make it harder for amphibians to cope with heat.
As ectotherms, amphibians control their body temperature through external sources, including warming up by basking in the sun, or cooling down using water, shade and cool spaces underground. If they are unable to cool their body down, they may reach critical thermal maximum – the temperature at which they can no longer function.
Scientists measured this ability to function by the temperature at which they start having muscular spasms or the point at which they are unable to right themselves when flipped onto their back. In both cases, they are unable to escape the heat and will die.
To date, heat tolerance in amphibians had been measured in more than 600 species, so the scientists in the study built statistical models to predict the heat tolerance for more than 5,000 amphibians (60% of the known amphibian species – the current number of known species is just under 8,900).
Each species’ heat tolerance was compared to temperature data from the last decade, and then to different potential future temperatures calculated by various climate scenarios.
The scientists warn that local extinctions may occur, as amphibians usually cannot relocate to different areas, and habitat loss – or if those habitats become too hot – means that the species can no longer survive there.
“With increasing deforestation, habitat disturbance and droughts, amphibians are losing their ability to cope with the heat,” says Patrice Pottier, a postdoctoral researcher at The Australian National University, and lead author of the paper.
"Active efforts to protect, restore and connect forested areas and wetlands are increasingly needed to boost their chances of survival.”
Find out more about the study: Vulnerability of amphibians to global warming
Main image: common frog/Getty
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