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NSF Grant Funds Study of Biological Diversity in Wake of Ice Age

Ice ages over the past few million years caused glaciers to expand and sea levels to drop, intermittently exposing a section of sea floor between eastern Russia and northwest Alaska that became the Bering Land Bridge. This connector served as a migration route for humans, animals and plants. It had a significant impact on the biology of North America.

Kurt Galbreath (Biology) has received a $225,000 National Science Foundation grant to fund his role in a collaborative study on patterns of biological diversity established over the course of these climatic changes. He and two NMU students completed field work in Canada’s Yukon and Northwest Territories this summer. Future studies with colleagues from other institutions are planned in Siberia, the Great Lakes region and elsewhere in Canada. The overall goals are to explore how mammals, parasites and plants are distributed across the North American landscape and the historical processes that assembled these ecological communities.

“Our focus is on mammals and parasites across more northern latitudes that have been neglected in terms of understanding patterns of diversity,” said Galbreath, who started related research more than a decade ago as a master’s student. “We hope to shed some light on that by collecting specimens, bringing them back to the lab and using molecular tools to extract DNA for genetic signals that offer clues about population changes.

“As primary consumers, small mammals are sensitive to changes in their environment. We can study patterns of genetic diversity to detect signatures of population fragmentation, interbreeding, growth or decline. These events can be related to factors such as climate warming or cooling. Our research can be used to develop a predictive model of organism responses to climate changes. And our field collections establish a baseline that will allow us to detect environmentally induced changes through resampling later.”

Galbreath took NMU undergraduate student Dan Houvener and graduate student Heather Toman to the Yukon to network with a field crew from the University of New Mexico, one of two other universities participating in the project. The teams established protocols for using and managing data. They also connected with local wildlife agency personnel who had previously collected small mammals.

“Agency biologists often conduct small mammal surveys to determine populations in a particular area. They’re left with freezers full of carcasses that could either be thrown away, which is a waste, or processed by us and archived as museum specimens. We collect measurements, reproductive information and specimens such as tissue samples and parasites from every animal we process. The information is recorded in an online database that can be mined for other purposes. The local agencies don’t have to manage that data, but they have access, giving them a nice benefit from sharing their material with us.”

The NMU team was joined by Eric Hoberg, chief curator at the U.S. National Parasite Collection, for field work in the Northwest Territories. The team trapped and processed mammals “from squirrel size down to shrews” in the hope of sampling as much diversity as possible to serve as a basis for subsequent research.

“The first step is determining what species are found where now. Then you look at how they came to be there and how they interacted with established species upon their arrival. The mammal and parasite specimens we collect are archived in appropriate collections such as NMU’s Museum of Zoology, which is housed in the biology department, to provide the base for a whole range of potential research projects. A major strength of the museum-based approach is that your research is always backed up by a permanently accessible physical specimen to use for comparison purposes.”

On a related note, Galbreath was awarded reassigned time from NMU for the fall semester to enhance the university’s biological collections, some of which date back to the early 1900s.