Climate change threatens Northern American turtle habitat

October 8, 2013, National Institute for Mathematical and Biological Synthesis
This is a Terrapene carolina, or eastern box turtle, near Lake Poinsett, Arkansas in 2013. Credit: Beth A. Reinke

Although a turtle's home may be on its back, some North American turtles face an uncertain future as a warming climate threatens to reduce their suitable habitat.

A new study that reconstructs the effects of past climatic changes on 59 of North American turtles finds that the centers of the turtles' ranges shifted an average of 45 miles for each degree of warming or cooling. While some species were able to find widespread suitable climate, other species, many of which today are endangered, were left with only minimal habitat.

Species in temperate forests and grasslands, deserts, and lake systems, primarily in the Central and Eastern US, were more affected by than species occurring along the Pacific Coast, in the mountain highlands of the Western US and Mexico, and in the tropics, according to the study published today in the journal PLOS ONE.

The study integrates data from more than 300 published studies on turtle physiology, genetics, and fossils with new models of species' response to climate-change cycles over the last 320 millennia to draw its conclusions. During this timeframe, Earth passed through three glacial-interglacial cycles and significant variation in temperature.

In this Science Minute from NIMBioS, Dr. Lawing explains the science behind her study of how climate change might affect turtle habitat. Credit: Catherine Crawley/NIMBioS
"By studying how turtles responded to these , we can learn about regional differences of the impact of climate change, how climate change differently impacts species, and how climate has influenced evolution," said co-lead author Michelle Lawing, a postdoctoral fellow at the National Institute for Mathematical and Biological Synthesis.

Quantifying niche conservation in historical time scales is crucial to estimate future extinction risks due to climate change, explained co-lead author Dennis Rödder, curator for herpetology at the Leibniz-Institute for Terrestrial Biodiversity Research at the Zoologisches Forschungsmuseum Alexander Koenig in Bonn, Germany.

"This study, which for the first time comprehensively integrates all available information for the majority of all North American turtle species, provides profound evidence of how global warming will affect the genetic architecture of the turtles," Rödder said.

The research suggests that the rate of climate change today is much faster than the turtles' ability to adapt naturally and evolve to tolerate the changes. Turtles will have to continue to shift their geographic ranges to keep up with the changing climate, yet new real estate for the turtles might be running out.

"In the past, turtles have coped with climate change by shifting their geographic ranges to areas with more compatible climates. However, it is more difficult for modern turtles to do that with today's managed waterways and agricultural and urban landscapes," said co-author David Polly, professor of geological sciences at Indiana University.

More than half of the world's approximately 330 species of turtles and tortoises are threatened with extinction due to illegal trade and habitat loss, according to the Red List maintained by the International Union for Conservation of Nature. Turtles and tortoises, which evolved about 220 million years ago, are at a much higher extinction risk than many other vertebrates, paralleled only by primates, according to the IUCN. Many of the most threatened and tortoises are in Asia.

Explore further: A lot less sea turtles arriving in Nicaragua

More information: Rödder D, Lawing AM, Flecks M, Ahmadzadeh F, Dambach J, Engler JO, Habel JC, Hartmann T, Hörnes D, Ihlow F, Schiedelko K, Stiels D, Polly DP. 2013. Evaluating the significance of paleophylogeographic species distribution models in reconstructing quaternary range-shifts of Nearctic Chelonians. PLOS ONE.

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1.3 / 5 (16) Oct 08, 2013
Why are you saying a crisis will happen when science has agreed for 30 years on nothing beyond "could be"? Every climate change believer must do as science does; never say a crisis will happen inevitably or eventually.
4.3 / 5 (6) Oct 08, 2013
You You You retard has been asking the same stupid question for years, and getting the same answer for years.

His willful conservative ignorance makes him incapable of learning.

He and people like him are one of the reasons why American's are growing dumber with each passing day.

4.8 / 5 (5) Oct 09, 2013
Canada currently is suffering from a Conservative government, so the corruption and control of science is one of their government's primary goals.
1 / 5 (16) Oct 09, 2013
Fact; It hasn't statistically warmed for nearly 17 yrs. Are the authors aware of this? Do they care? Or is it just their political agenda like blogger angry child vendicarE?

"The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary. " H.L. Mencken
4.8 / 5 (4) Oct 09, 2013
"Fact; It hasn't statistically warmed for nearly 17 yrs." - DeaTard

That's weather for you.

The topic here is climate, and even after being told the difference a dozen times, if not more, you still repeat the same stupidity.

What is your excuse? Brain damage? Pure ignorance? An inability to learn?
1 / 5 (16) Oct 14, 2013
Oh nose!! Not da turtle...not da turtle.

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