Risk of interbreeding due to climate change lower than expected

climate change
Satellite image of ship tracks, clouds created by the exhaust of ship smokestacks. Image: NASA

One of the questions raised by climate change has been whether it could cause more species of animals to interbreed. Two species of flying squirrel have already produced mixed offspring because of climate change, and there have been reports of a hybrid polar bear and grizzly bear cub (known as a grolar bear, or a pizzly).

"Climate change is causing species' ranges to shift, and that could bring a lot of closely into contact," said Meade Krosby, a research scientist in the University of Washington's Climate Impacts Group.

She is the lead author of a study published July 6 in Nature Climate Change that tallies the potential number of such pairings. Looking across North and South America, it finds that only about 6 percent of closely related species whose ranges do not currently overlap are likely to come into contact by the end of this century.

"People have been concerned that would be bringing all these species into contact, and that this could unleash a wave of interbreeding," Krosby said. "What we found is, not so much."

A 2010 editorial in the journal Nature suggested that northern species may begin to interbreed and create a so-called "Arctic melting pot," and even prompted one artist's rendition of what those new offspring would look like.

The idea also worried looking at how to prepare for climate change. At a workshop, land managers told Krosby they worked with very closely related species separated by small distances. What if managers linked the two areas with a wildlife corridor, and as the climate changed the species started to mix?

This study is an attempt to see how much that should be a concern. It looked at 9,577 pairs of closely related species of birds, mammals and amphibians in North and South America. For the 4,796 pairs whose ranges currently do not overlap, computer models show that only 6.4 percent of them will come into contact due to climate change by the year 2100.

The most overlap among species occurred in the tropics, and among birds, likely because more species live in the tropics and birds cover wider ranges, Krosby said.

While the study suggests that climate change is unlikely to result in widespread interbreeding, wildlife biologists still need to consider their particular region and animals of interest to best protect specific populations.

"Managers still need to look case-by-case at species at a local scale, but at a global scale, the big picture is that it's probably not going to be a huge problem," Krosby said.

The study likely overestimates how many species could be at risk of interbreeding because it assumes that all species will be able to access new habitats that become available due to climate change. In fact, natural barriers prevent animals from reaching all potential new habitats, and humans have created new barriers such as highways, farms, and cities that can block migrations to more hospitable places.

"The number one strategy for helping biodiversity respond to climate change is to increase connectivity, to link up habitats that have been fragmented by human activity, so species can move, and track climate as it shifts to stay comfortable," Krosby said.

"If people are worried that wildlife corridors and other ways to increase connectivity could bring these species into contact, we're saying: That's probably not going to happen, and allowing species to move is far more important."

Krosby did her doctoral work looking at how historic climate changes affected species in the past, including how the end of the last ice age led to interbreeding among West Coast songbirds. Now she focuses on contemporary climate change, to see how are responding and how land managers can best protect biodiversity under faster, human-driven changes to Earth's climate.


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Changes in birds' ranges may greatly affect ecosystems

More information: Climate-induced range overlap among closely related species, DOI: 10.1038/nclimate2699
Journal information: Nature Climate Change , Nature

Citation: Risk of interbreeding due to climate change lower than expected (2015, July 6) retrieved 25 June 2019 from https://phys.org/news/2015-07-interbreeding-due-climate.html
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Jul 06, 2015
how land managers can best protect biodiversity under faster, human-driven changes to Earth's climate.

One can't help but be alarmed.

Not content with fascism, communism and socialism, humans are now turning their need to control others to wildlife; nay, the very process that leads to species diversity. All of it rationalized by "human-driven changes to earth's climate".

History's judgement of these days will not be kind.

Jul 06, 2015
why would greater interbreeding of wild species be a bad thing?
I don't understand why they refer to this as a "risk" as if it is a bad thing.

Suppose many gray squirrels interbred with red squirrels so to cause the birth of a new hybrid species of squirrel. Why would that be a bad thing? Exactly what harm would it do and exactly how so?

Jul 06, 2015
Oh, gloBULL warming, look at what you have gone and done now!

Jul 06, 2015
You guys are nuts.
Actually look at how thin the atmosphere is:
d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2009/08/earth_sts118_big.jpg

Also if you guys cannot understand basic atmospheric chemistry, please don't start butchering biology as well. Evolution dictates everything is a product of its environment, life as it is today has been written by the history of earths climate.
You guys can not fully understand one without the other because you find yourself being contradictory to your past statements.

Jul 06, 2015
It only appears thin to someone with your thick skull.

Jul 06, 2015
Humy,
Different kinds of squirrels are different species for a reason
For example, they might eat different food sources, which means a plant that evolved to have its seeds spread by squirrel X may no longer have any means of spreading competitively. Soon you have a tree species in trouble which in turn causes more losses in biodiversity.
Maybe squirrel X evolved to be suited for a cold climate and squirrel Y evolved in a warm. Instead of just squirrel X going extinct, it breads with squirrel Y creating XY squirrels that can not tolerate the warm climate as well as a regular squirrel Y. Then you could have squirrel Ys dying off through genetics, but as this article stated, this is probably not much of a concern.

Jul 06, 2015
Goracle,
That big land mass is the tiny boot of Italy. The atmosphere is very thin.

Jul 06, 2015
Steve, as a method of justifying the need to control wild animal breeding habits because of AGW, the picture fails. Pictures like that don't indicate the thickness of the atmosphere, nor do yuo explain how the "thickness" of the earth's atmosphere has any relation to climate change.

The concern with thinking that one should alter the breeding habits of animals is that we do not know what the earth's climate will do next. Wildlife, as all life, must find a way to adapt, or it will die. Mother Nature gives life, and takes it away with no feelings of personal involvement. We should follow her example.

it is a neat picture though.

Jul 07, 2015
Humy,
Different kinds of squirrels are different species for a reason
For example, they might eat different food sources, which means a plant that evolved to have its seeds spread by squirrel X may no longer have any means of spreading competitively. Soon you have a tree species in trouble

Have you got any evidence that this is would likely be the case?

which in turn causes more losses in biodiversity.

With all else being equal, wouldn't a birth of a new hybrid species mean an increase in biodiversity?

Maybe squirrel X evolved to be suited for a cold climate and squirrel Y evolved in a warm. Instead of just squirrel X going extinct, it breads with squirrel Y creating XY squirrels that can not tolerate the warm climate as well as a regular squirrel Y. ,

If that is so, natural selection would work in favour of Y over XY as the climate warms thus Y will thrive at the competitive expense of XY. I don't see how that would be a bad thing.

Jul 11, 2015
Oh, no...Evolution

GAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHH

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