New Study Says Global Warming Not Leading To Lizard Extinction

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Some like it hot. Anolis allisoni on Roatan, an inhabitant of open areas, will benefit from increased global temperatures. Photo by J. Losos.

Thanks to HerpDigest, a regular email compendium of herpetological news, here is a press release on a recent paper in Global Change Biology:

A new Dartmouth College study finds human-caused climate change may have little impact on many species of tropical lizards, contradicting a host of recent studies that predict their widespread extinction in a rapidly warming planet.

Most predictions that tropical cold-blooded animals, especially forest lizards, will be hard hit by climate change are based on global-scale measurements of environmental temperatures, which miss much of the fine-scale variation in temperature that individual animals experience on the ground, said the article’s lead author, Michael Logan, a Ph.D. student in ecology and evolutionary biology.

To address this disconnect, the Dartmouth researchers measured environmental temperatures at extremely high resolution and used those measurements to project the effects of climate change on the running abilities of four populations of lizard from the Bay Islands of Honduras. Field tests on the captured lizards, which were released unharmed, were conducted between 2008 and 2012.

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Anolis bicaorum, a denizen of closed forest, from Utila, Honduras. Photo by J. Losos.

Previous studies have suggested that open-habitat tropical lizard species are likely to invade forest habitat and drive forest species to extinction, but the Dartmouth research suggests that the open-habitat populations will not invade forest habitat and may actually benefit from predicted warming for many decades. Conversely, one of the forest species studied should experience reduced activity time as a result of warming, while two others are unlikely to experience a significant decline in performance.

The overall results suggest that global-scale predictions generated using low-resolution temperature data may overestimate the vulnerability of many tropical lizards to climate change.

Another photo of A. allisoni, just because they're so cool. Photo by J. Losos

Another photo of A. allisoni, just because they’re so cool. Photo by J. Losos

“Whereas studies conducted to date have made uniformly bleak predictions for the survival of tropical forest lizards around the globe, our data show that four similar species, occurring in the same geographic region, differ markedly in their vulnerabilities to climate warming,” the authors wrote. “Moreover, none appear to be on the brink of extinction. Considering that these populations occur over extremely small geographic ranges, it is possible that many tropical forest lizards, which range over much wider areas, may have even greater opportunity to escape warming.”

An example of open habitat, from the island of Cayo Menor. Photo by Mike Logan.

An example of open habitat, from the island of Cayo Menor. Photo by Mike Logan.

An example of closed forest, from the island of Roatan. Photo by Mike Logan.

An example of closed forest, from the island of Roatan. Photo by Mike Logan.

Story Source: The above story is reprinted from materials provided by Dartmouth College, via EurekAlert!, a service of AAAS.

Jonathan Losos
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3 Comments

  1. GW will surely take out some high montane species. It is already affecting salamanders.

  2. Fred Gibson

    Things will change, whether “man made” causation, or periodic asteroid impacts or any other infinite number of variable scenarios. Some things will live through aa change, for a while, until another change happens, others will be wiped out, and yet some others will see themselves change slightly over generations, branching off and forming new combinations of carbon and calcium, electricity, water and so forth. This is the universe we live in, and while it’s fun to compile information and speculate, ultimately, we have no control. There’s no “invasive” species, there’s no “saving the planet” and no crisis of excess carbon. Only the shifting about of what has already been here. We cannot at any point in time, freeze the state of the world to proclaim “this is how it should be”. It is an ever moving dynamic relationship for which we have but the briefest of intergalactic moments of experience and influence. Immerse yourself in the Now, and celebrate your moment fully for what it is, while it is. 🦎

    • Steven A. Nole

      True, buts it’s still fun to speculate on which anole species will evolve into anolosaurus rex millions of years from now, and which will evolve into anolociraptor.

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