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Latest Study Shows Warming Climate Forcing Alpine Chipmunks To Yosemite National Park's Roof


Warming temperatures seem to be forcing alpine chipmunks towards higher elevations in Yosemite National Park. Once they were commonplace in the rocky slopes above Tuolumne Meadows, according to researchers. Top photo by Cole Burton, bottom photo by Risa Sargent.

Not only is a warming world forcing a tiny chipmunk towards the roof of Yosemite National Park, but it appears to be eroding the genetic diversity of the species as well, according to a study by University of California, Berkeley, researchers.

While it wasn't too long ago that you could hear the squeaking chipmunks and watch their frantic movements in the rocky slopes above Tuolumne Meadows, today the species has vanished from those rockfields, according to the study, which appeared in the Nature Climate Change on-line edition Sunday.

According to a release from the university, the study "is one of the first to show a hit to the genetic diversity 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 changing climate can pose to a species."

Without rich genetic diversity, a species can be hit by a cascading array of problems, such as inbreeding and disease, the researchers note.

“Climate change is implicated as the cause of geographic shifts observed among birds, small mammals 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.”

Dr. Rubidge worked with Craig Moritz, professor of integrative biology and director of the Museum of Vertebrate Zoology; James Patton, professor emeritus of integrative biology 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 Yosemite National Park 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 Professor 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 Mr. 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.”

Professor 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 the professor. “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.”

Other study co-authors are Marisa Lim, a UC Berkeley undergraduate student in integrative biology; and Cole Burton, former UC Berkeley graduate student in environmental science, policy and management (now a research associate at the University of Alberta in Canada).

Funding for this research was provided by the Natural Sciences and Engineering Research Council of Canada, UC Berkeley’s Museum of Vertebrate Zoology, the Yosemite Fund, the National Geographic Society and the National Science Foundation.


"Dumbing down of America is not progress?"  That what's lead us into this mess!  It is kind of a statement of things when the smartest of smart put a constituency together of the well connected and the 49.5 % that pay no Federal taxes.  Sounds like third world to me:).  Could be pushing Kurt's limits here but say it isn't so Rick B.

Nothing like a little climate change discussion to bring out the rabid "anonymous" folks. 

And since when is the simple fact of having been educated a bad thing? The dumbing down of America is not progress. It is possible to both be educated and to 'get things done'. 

Anon: The attitude that one knows better than everyone else with nothing but an academic background leaves a void in the "get things done" area of the brain.  Collateral damage is evident in most all enterprises which explains the Sierra Club and the PR wars.  The belief that the Sierra Club has the one true and sacred mission is the idiocy.  Try God as the supreme being as opposed to mother earth.  I'm sure the "get things done" deal invites all the extreme screwup defense but real life experiences is invaluable to solving the problems with science being a collaborative partner.  Anybody with a Fedseral job should know how difficult it is to get anything done especially something that is actually problem solving in the truest sense.

To both/same ? Anonymouses (8:33 & 9:32)
Your feedback illustrates why quality Natural Science education is so critical in Public/Private Schools because
if you have no basis or early background in a discipline, beginning from point zero truly requires positive
serious motivation and devotion.  The Dinos and Humans never co-existed; read theories on large asteroids
striking Earth to understand current Extinction thinking.  This feedback opportunity is only valuable if
participants truly engage in a serious manner to learn from others.  Connecting the Sierra Club's Mission
with wolverine survival/persistence is clearly idiotic. Amen !

Interesting stuff.  Always change going on.  Wonder if man had anything to do with the Dinasaurs dissapearing?   Some have said that the Sierra Club is more responsible for the disappearance of Wolverines in the Sierras than any climate issue.  Information offered me by some "inside" the environmental culture but not willing to be quoted for obvious reasons. 

Thanks for the link but it doesn't answer any of my questions - only adds some.  For example why did "global warming" not impact the closely related T. speciosus?

And of course the biggest question is...... so what?

Many references to understand Effects of Global Climatic Change on SpeciesMigrations: for example:  [color=#0000ff][/color]
 News: Berkeley-based scientist causes ethics storm over climate change documents (Fighting Fire with Fire to reveal Heartland Inst. Biases-Lies & How to Dumb Down Public Schools)Dana Hull and Paul Rogers/San Jose Mercury News Staff Posted:   02/23/2012 02:15:55 AM PST
  For the past two decades, Peter Gleick has earned a reputation as a nationally known expert on water and climate issues, winning a MacArthur “genius award,” penning a long list of scientific articles and testifying before Congress. But over the past two days, the 55-year-old Berkeley resident has found himself at the center of a national maelstrom of his own making: using a false name to obtain confidential documents from a pro-industry think tank known for minimizing the risks of global warming.

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