TUCSON, Ariz. — Climate change can be a controversial topic, and many are not convinced that it actually exists. However, new research on a lizard species from southeastern Arizona reveals shocking evidence of rapidly accelerating extinction driven by climate change. More precisely, researchers discovered 70 years of climate damage in just seven years!
University of Arizona researchers studied Yarrow spiny lizard populations in 18 mountain ranges across the state, analyzing the rate of climate-related extinction over time.
“The magnitude of extinction we saw over the past seven years was similar to that seen in other studies spanning nearly 70 years,” says John J. Wiens, professor in the Department of Ecology and Conservation. evolutionary biology and lead author of the study. , in a university outing.
The Yarrow spiny lizard is native to southwestern United States (and western Mexico) and can be seen in the oak and pine forests of 18 mountain ranges in Arizona’s Sky Islands.
To begin with, the research team carried out a series of initial surveys of the Yarrow spiny lizard in these mountain ranges between 2014 and 2015. Then, in 2021 and 2022, Professor Wiens, together with Kim Holzmann, his former student master’s degree and lead study author and Ramona Walls, a part-time researcher at the BIO5 Institute at UArizona, collaborated to resurvey these areas and determine whether changes in lizard populations had developed. since then.
By conducting the surveys, the study authors discovered about half of the lizard populations in lower altitudes had disappeared. This was likely due to temperatures becoming warmer at lower altitudes, with lizards living nearby likely not being able to tolerate more heat. The loss of low-lying populations is a characteristic pattern of climate change, researchers say.
“THE extinction rate in such a short time, it was shocking,” adds Professor Wiens.
After comparing their work to historical records from the same mountain ranges, the researchers estimate that the average extinction rate of low-altitude lizard populations has triple in just the last seven yearscompared to the previous 42 years.
While previous projects did predict that climate-related extinctions would increase as global warming continues, Professor Wiens notes that he has not seen any reports showing such a rapid acceleration in extinction before. Worse, the study adds that a distinct 3-million-year-old lineage of Yarrow’s spiny lizard native to the Mule Mountains (near Bisbee) may be entirely extinct. from 2025.
“Low elevation populations of Mules were doing well in 2014. Today, the only ones we found were about 300 feet from the top of the mountain in 2022, and they appear to have lost about 170 feet per year,” explains the researcher.
It is important to clarify that not all lowland populations disappeared between surveys. For example, the researchers note that two populations present at very low altitudes have survived. Before their disappearance, the research group collected genomic data on most lizard populations between 2014 and 2015. Access to this data allowed the researchers to conclude that the lizard populations that were less genetically distinct and those most exposed to the effects of climate change are those that tend to become extinct in most cases, suggesting that populations with less genetic variation have less capacity to cope with climate change.
In the future, Professor Wiens’ research group wants to carry out further studies focusing on the extinction and survival mechanisms of Yarrow spiny lizards living in these mountain ranges. The researchers also plan to set up similar projects with others species of lizard native to even warmer regions like Death Valley in California.
The study authors emphasize the importance of studying the influence of climate change on biodiversity on shorter time scales, rather than only looking for changes after decades.
“We have now demonstrated that the effects of climate change can be devastating over very short periods of time,” concludes Professor Wiens.
THE study is published in the journal Ecology letters.
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