Deforestation Could Put 84% of North American Lizards at Risk, Study Says

Deforestation is making lizards in North America more vulnerable because of a lack of shelter from extreme temperatures, according to a new study.

Led by scientists at University of Colorado Boulder and Tel Aviv University, the study found that forest loss, alongside climate change, could negatively impact 84% of lizards in North America by 2100. The findings were published in the journal Nature Climate Change.

This is because extreme temperatures, like a summer heat wave, are particularly risky for lizards, who need to seek shade to cool down or sunlight to get warm. These cold-blooded creatures often use trees to help thermoregulate.

“What’s really interesting about lizards is that they just need to be able to move a short distance around the tree trunk to get to a very different climate and habitat environment,” Keith Musselman, an assistant professor at University of Colorado Boulder, said in a statement. “These microhabitats are particularly important when we think about how we modify our natural environment and make conservation decisions.” 

According to the study authors, deforestation could decrease the amount of time lizards spend seeking food or reproducing, called activity time, by 34%. Further, the tree loss and decline in activity time could cause quicker population declines for 18% of North American lizards.

“Here in the Rocky Mountains, elevation provides an escape for animals that can travel longer distances, including us humans. On those summer days when it hits 100 degrees, many of us will go into the mountains,” Musselman said. “But small animals like lizards can’t travel far. They heavily depend on the refuge provided by the local landscape, including tree trunks.”

Lizards are an important part of their ecosystems, and population declines could also disrupt other species, the scientists warned.

According to Global Forest Watch, the U.S. lost 46.5 megahectares (Mha) of tree cover and Canada lost 48.9 Mha from 2001 to 2022.

The findings reveal the vulnerabilities of cold-blooded animals, particularly when it comes to forest loss. The authors noted that while global warming can actually offer some benefits for these animals, vegetation loss from deforestation and other impacts of climate change, such as wildfires, can reverse any potential benefits and still lead to population declines.

Omer Zlotnick, first author of the study and a Ph.D. student at Tel Aviv University, said, “Deforestation is a worldwide problem, and our conclusions can help decision-makers on other continents in designing conservation and habitat restoration programs that consider climate change.”