BBC: Scientists have begun to predict the animals that may become extinct in the next century because of climate change.
Researchers at Brown University in the US have combined predictions of climate change with the geographic ranges of well-studied amphibians.
While the animals will try to migrate to areas with more suitable weather, short-term temperature fluctuations can cut them off.
The findings suggest more effort should be made to relocate vulnerable species. It has been recognised for the past decade that the continuing future trend of global warming may drive species to permanently migrate in order to stay in an ideal habitat.
Amid concerns that this long-term migration may be disrupted by towns and cities, scientists at Brown University Dr Regan Early and Prof Dov Sax set out to predict the shifts in species’ ranges over the next century.
Predictions of global climate change generally show warming trends, though both global annual oscillations and local climatic effects will play a role for given species.
The researchers combined these climate models with information on the ranges and tolerances of various species of frogs, toads and salamanders in the western US, with results that “really surprised”, said Dr Early.
While they set out to find the disrupting effect of urban areas, they instead saw that the short-term climate fluctuations were enough to stop a species’ migration in its tracks, cutting it off from ideal habitats and driving it to extinction.
They have published their results in the journal Ecology Letters.
Physical tolerance
Fifteen species of amphibians native to the western US were modelled in the study, as their ranges are well-known and their tolerances to physical extremes have been well-studied.
While none of these species is currently at risk, they predicted that over half of them would become extinct or endangered in the next 100 years due to these climate fluctuations.
Among the factors determining whether a species would survive were the speed at which it can migrate and its persistence, or robustness, in the face of climatic change.
For example, the models suggested that the Foothill Yellow-Legged frog would be able to make it into a new area, despite climate fluctuations, while the California newt would not fare so well in its migration across the Californian Central Valley.
Dr Early said: “This species isn’t endangered now, and in the future there is more than enough suitable habitat for it to remain safe, but…the newt has a really hard time following its climate path to its future range because repeated climatic fluctuations cause it to retreat over and over again.”
The tolerance of an animal to less-than-ideal climatic conditions will determine whether it can survive long enough to complete its migration.
“There is a lot of uncertainty in the ability of species to persist, and this is an under-appreciated factor,” said Dr Early.
