Yosemite's alpine chipmunks take genetic hit from climate change

Feb 19, 2012
An alpine chipmunk (Tamias alpinus) is shown at Yosemite's Ten Lakes Pass at an elevation of 9,631 feet. Credit: Risa Sargent photo

Global warming has forced alpine chipmunks in Yosemite to higher ground, prompting a startling decline in the species' genetic diversity, according to a new study by researchers at the University of California, Berkeley.

The study, appearing Sunday, Feb. 19, in the advance online publication of the journal Nature , is one of the first to show a hit to the of a species because of a recent climate-induced change in the animals' geographic range. What's more, the genetic erosion occurred in the relatively short span of 90 years, highlighting the rapid threat can pose to a species.

With low genetic diversity a species can be more vulnerable to the effects of inbreeding, disease and other problems that threaten , the researchers said.

"Climate change is implicated as the cause of geographic shifts observed among birds, and plants, but this new work shows that, particularly for mountain species like the alpine chipmunk, such shifts can result in increasingly fragmented and genetically impoverished populations," said study lead author Emily Rubidge, who conducted the research while a Ph.D. student at UC Berkeley's Museum of Vertebrate Zoology and the Department of Environmental Science, Policy and Management. "Under continued warming, the alpine chipmunk could be on the trajectory towards becoming threatened or even extinct."

Rubidge worked with Craig Moritz, professor of integrative biology and director of the Museum of Vertebrate Zoology; James Patton, professor emeritus of and curator of the Museum of Vertebrate Zoology; and Justin Brashares, associate professor in the Department of Environmental Science, Policy and Management.

The new findings build upon previous research that found major shifts in the range of small mammals in since the early 1900s. In 2003, biologists at UC Berkeley began an ambitious resurvey of Yosemite's birds, mammals, reptiles and amphibians, retracing the steps originally taken between 1914 and 1920 by Joseph Grinnell, founder and former director of the Museum of Vertebrate Zoology.

The Grinnell Resurvey Project, led by Moritz and museum colleagues, found that many small mammals in Yosemite moved or retracted their ranges to higher, cooler elevations over the past century, a period when the average temperature in the park increased by 3 degrees Celsius, or about 5.4 degrees Fahrenheit.

It is no surprise that the alpine chipmunk (Tamias alpinus) would be more sensitive to the temperature change, since it is a high-elevation species endemic to California's Sierra Nevada, the researchers said. In the early 1900s, Grinnell and colleagues sighted alpine chipmunks at elevations of 7,800 feet. Now, the alpine chipmunk appears to be sticking to even higher elevations, retracting its range by about 1,640 feet upslope.

To test the genetic impact from that loss of geographic range, researchers compared genetic markers from 146 modern-day alpine chipmunks with those from 88 of their historical counterparts. Samples were collected from seven paired sites throughout Yosemite.

As a control, the researchers also looked at the genetics – both historic and modern – of lodgepole chipmunks (Tamias speciosus), a lower elevation species that had not changed its range over the past century.

The analysis of genetic markers revealed a significant decline in "allele richness" among the recently sampled alpine chipmunk populations compared with their historic counterparts. Moreover, the researchers noted that the modern chipmunks were more genetically differentiated across sites than in the past, a sign of increased fragmentation in the alpine chipmunk population.

In comparison, there were no significant changes in genetic diversity detected among the lodgepole chipmunks, a species found at elevations from 4,900 to 9,800 feet.

"Much of what we read and hear about the effects of climate change on biodiversity is based on model projections and simulations, and these models typically involve many moving parts and lots of uncertainty," said Brashares. "Thanks to the baseline provided by Joseph Grinnell's pioneering efforts in the early 20th century, we are able to go beyond projections to document how climate is altering life in California. The research led by Emily is novel and important because it shows empirically that climate change has led to the loss of genetic diversity in a wild mammal over the last several decades."

Moritz added that this study exemplifies how patterns of change in California's ecosystems can be uncovered through analyses of fossil, historic and modern records.

"At the heart of this whole enterprise is the incredibly dense historic record and specimens we have at UC Berkeley from 100 years ago," said Moritz. "These collections allow us to conduct sophisticated analyses to better understand how ecosystems are reacting to environmental changes, and to create more detailed models of future changes."

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User comments : 13

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Jeddy_Mctedder
2.2 / 5 (10) Feb 19, 2012
this is why so many people think global warming and climate change is proporganda. because of crap research like this that gets funded just because of the buzz words used in the grant proposal. you can't just 'study' chipmunks.
RazorsEdge
3.3 / 5 (7) Feb 19, 2012
Why does the cause have to be global warming? I'd look at the increase in the number of tourists, hikers, and rock climbers. This would also explain the difference with lodgepole chipmunks, who can easily flee up a tree to avoid being trampled.
Sean_W
2.3 / 5 (9) Feb 19, 2012
Let's see the temperature data. Unadjusted data, that is. And unfaked if possible.
debolton
2.3 / 5 (6) Feb 19, 2012
This is nothing but another try at fooling the public. Notice that this is the Berkley Left reporting; they will tell you what they want to tell you as long as it achieves their desired results. Jeddy Mctedder and RazorsEdge both hit the mark right on the square. I am embarrassed to see this is from UC Berkley as it is my taxes that support it; however, I'm not supprised.
aroc91
4 / 5 (8) Feb 19, 2012
Why does the cause have to be global warming? I'd look at the increase in the number of tourists, hikers, and rock climbers. This would also explain the difference with lodgepole chipmunks, who can easily flee up a tree to avoid being trampled.


Considering that this has been observed many other types of animals and plants as well, I'd say direct human activity doesn't have anything to do with it.
deepsand
4.3 / 5 (12) Feb 19, 2012
Nice to see all of the know nothings pontificating, wholly oblivious to the facts that such effects are observed in more than a few species of fauna, and in areas visited only by researchers.

DrSki
3 / 5 (2) Feb 19, 2012
WOW!
Species actually adapting to environmental changes!
If only the dinosaurs were able to adapt as well - more of them would probably be around. ;-(
I wish I was in EASTERN EUROPE this winter.........
Shelgeyr
1.3 / 5 (12) Feb 19, 2012
See, deepsand, this is why you and the other leftists have no credibility at all. Someone offers an opinion you don't agree with, and immediately you're onto the personal attacks, saying that they're "...know nothings pontificating, wholly oblivious...".

It is obvious you don't have an actual intelligent reply to offer, much less a rebuttal, so you have to reach for the insults.

In short, as with the other trolls, your opinion simply doesn't matter.
deepsand
4.3 / 5 (12) Feb 19, 2012
A factual observation re. the ignorance under which another is laboring is not a personal attack.

The fact that such here opine in the absence of factual support not only nullifies such opinions, but speaks to their biases as well.

While all all entitled to their own opinions, none are entitled to their own facts, something that you and many others adamantly refuse to understand and accept.

All opinions are NOT equal.

Furthermore, you use of "leftist" here is not only a conclusion based on facts not in evidence, but is intended as pejorative, thus making you a hypocrite for engaging in argumentum ad hominem while in the same breath yourself engaging in such.
Vendicar_Decarian
0.8 / 5 (43) Feb 19, 2012
Translation: I am a denialist moron who will attack any science that contradicts my Conservarive Denialist, Anti-Science religion.
I have faith that the lies told to me by Anti-Science marketing companies like the Heritage Foundation must be true because if they aren't then I would be forced to accept the reality of the need for progressive change, and I am a coward who fears change.

"this is why so many people think global warming and climate change is proporganda. because of crap research like this" - Jeddy
Vendicar_Decarian
0.9 / 5 (44) Feb 19, 2012
"Why does the cause have to be global warming?" - RazorsTard

The animals are altering their range in order to stay within their preferred micro-climate. This is quite clear from the article.

Cool micro-climates are becoming physically smaller as the surface of the planet warms and as a result there are fewer animals within those micro-climates, altered physical conditions, etc. These changes are reflected in the genetic makeup of the animals living in those micro-climates.

It isn't rocket science.
Vendicar_Decarian
0.8 / 5 (43) Feb 19, 2012
Shelgeyr, like all anti-science denialists are incapable of distinguishing between anti-science opinion and fact.

Conservatives like Shelgeyr believe that opinion and fact carry the same weight.

Their belief in non-reality explains why America is an intellectual basket case, and a failed nation.

"Someone offers an opinion you don't agree with, and immediately you're onto the personal attacks, saying that they're "...know nothings pontificating, wholly oblivious..."." - Shelgeyr
deepsand
4.3 / 5 (11) Feb 20, 2012
Conservatives like Shelgeyr believe that opinion and fact carry the same weight.


Noted at very long time ago. That's why I've taken to smacking them up-side the head with a two-by-four, so as to first get their attention.