Habitat shifts reducing chipmunks’ genetic diversity

As temperatures in Yosemite National Park have warmed more than five degrees Fahrenheit over the past 100 years, alpine chipmunks have shifted their habitat from 7,800-foot elevations to more than 9,400 feet.  The upslope migration to the cooler climes has fragmented populations of the small mammal, leading to isolated pockets of chipmunks that have become more genetically homogenous when compared to their historic counterparts. 

Conducted by researchers at the University of California Berkeley, the study suggests that “genetically impoverished populations” are more vulnerable to the effects of inbreeding, disease and other problems that threaten species survival. “Under continued warming, the alpine chipmunk could be on the trajectory towards becoming threatened or even extinct,” says the study’s lead author, Emily Rubidge. 

As noted  February 19 in the journal Nature Climate Change (subscription required), the chipmunk study is hailed as the first to empirically link a climate-driven geographic shift in habitat to a species’ loss of genetic diversity. 

Study relates genetic diversity to extinction vulnerability

Looking at genetic composition within plant species, authors of a paper published on line in the Proceedings of the Royal Society, Biological Sciences (available at no charge),  demonstrates the importance of genetic diversity in plants’ adaptive capacity and consequent survivability under changing habitat conditions.  

Species, the scientists say, respond to climate change through local adaptation, range shift, range reduction, or a combination of these actions. Range shift could increase genetic diversity within a species, while range reduction would reduce diversity and diminish the species’ adaptive capacity.   

A species’ method of seed dispersal and its growth form are traits that influence distribution of genetic diversity within and among populations. Considering these factors increases the accuracy of predicting a species’ genetic vulnerability due to climate change.   

Butterfly exhibits evolutionary adaptation to a changing climate

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British scientists studying the expanded distribution of the Brown Argus butterfly propose that variations in habitat preference exhibited among different populations of the insect improve the species’ adaptive capacity and promotes successful expansion of its range as climate conditions change.

The study (available free of charge) was conducted by scientists from the Universities of Bristol and Sheffield and published in Molecular Ecology. The authors undertook to “understand the role of evolution in helping a species to successfully track ongoing climate change.” Genetic variation in ecological traits throughout a specie’s distribution, the study posits, bolsters the speed and success of potential adaptation.