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Distinct Bison Herds Roam Yellowstone

January 29, 2007
University Of Montana
Graduate student Flo Gardipee studies fish and wildlife biology at The University of Montana, but she describes herself as "a professional pooper scooper." That's because she researches the feces of bison roaming Yellowstone and Grand Teton national parks.

Graduate student Flo Gardipee studies fish and wildlife biology at The University of Montana, but she describes herself as "a professional pooper scooper."

That's because she researches the feces of bison roaming Yellowstone and Grand Teton national parks. This involves following the massive creatures around -- staying upwind in case she needs to protect herself with bear spray -- and waiting for one to defecate. Then she quickly moves in for a sample. Because for Gardipee, the fresher the feces, the better the genetic material it contains.

"When you see that tail up and the feces dropping, you are like, 'yes!'" Gardipee explains. "I totally enjoy the humor of it."

So what's the scoop on bison poop? First, Gardipee has found a gentle, noninvasive way to study the DNA of the animals in the park. Secondly, the genetic material she and her team extracted suggests the roughly 4,000 bison in Yellowstone are divided into at least two distinct breeding groups, which could have implications for how they are managed.

"If one of these sub-populations is being culled in higher proportion to the other ones," she said, "then we could be losing some level of genetic diversity."

She said a 2003 study conducted by Natalie Halbert of Texas A & M suggested there may be up to three distinct sub-populations living in Yellowstone, but that effort relied on blood and tissue samples from bison wandering from the park to be captured, killed or tranquilized for other purposes. Helicopter net gunning was tried in the park, but was found to harm the animals. Gardipee said her method allows bison sampling inside the park within their specific geographic ranges.

"We don't have to round them up, rough them up or manhandle them in any way," she said. "We can just go out there and kind of be amongst them."

She said one of her advisers, UM Research Associate Professor Gordon Luikart, had done noninvasive DNA sampling previously with bighorn sheep droppings, but no one knew if a similar method would work for bison or cattle.

"We've had a fairly high success rate," Gardipee said. "More than 90 percent of our DNA samples are yielding sufficient DNA."

But the stuff has to be fresh. Compounds within the feces will destroy, disrupt and fragment DNA if it isn't placed in a preservative as soon as possible. Then back on campus, Gardipee and her assistant -- during months of work -- used a polymerase chain reaction to create biochemical photocopies of the DNA fragments they were interested in. These results were then sequenced to reveal the genetic codes of individual animals.

Gardipee uses mitochondrial DNA for her study since cells contain multiple copies of such material, making it easier to extract. Work continues on revealing nuclear markers -- called microsatellites -- which are harder to extract since each cell has only one nucleus. However, the nuclear markers will provide further insight with respect to population structure within the Yellowstone bison.

Gardipee obtained samples from the Grand Teton herd, as well as bison groups in Yellowstone's Hayden Valley, Lamar Valley and Mirror Plateau.

She said there are about a dozen known maternal lineages known in bison, and these are logged into GenBank, a worldwide database for genetic sequences. A maternal lineage also is known as a haplotype.

In Hayden Valley, they found only one haplotype -- haplotype 6 -- which means the roughly 2,000 animals living there may have lower genetic diversity. In Lamar Valley, home to about 900 bison, about 60 percent were haplotype 8 and the rest were haplotype 6. In the Mirror Plateau, about 65 percent were haplotype 6 and 35 percent were type 8. (All bison sampled from Grand Teton were haplotype 6.)

"This shows there is potentially a minimum of two different breeding groups in Yellowstone," Gardipee said. "Many people believe there is currently one breeding group in the park -- that there isn't any structure. But we are finding something different, at least at the mitochondrial level."

Bison are matriarchal, meaning they are led by their adult females when they go out to forage. Gardipee said her results indicate female bison in the park may have a strong attraction to their natal ranges -- the pastures where they were born. This behavior, known as female philopatry, could be part of the ecology of naturally regulated, free ranging, wild bison. This same behavior has been seen in other highly social mammals such as African elephants.

Gardipee said about 900 bison were slaughtered after they wandered out of Yellowstone last year because of fears they would spread an infectious disease called brucellosis to native cattle.

"But no one knew prior to our results that we might have separate breeding groups or any type of substructure in the park," she said. "No one knows, of the 900 animals that were sent to slaughter, how many came from each breeding group. If one breeding group is being culled disproportionately from another, we can lose lineages there. We can lose overall genetic diversity in the entire Yellowstone population."

Gardipee started her bison research after she won a competitive fellowship from the Boyd Evison Foundation, which is administered by Grant Teton National Park. The fellowship came with more than $10,000 to jumpstart her work, and Yellowstone National Park and other sources have raised her funding total to more than $20,000.

Born in Pennsylvania, Gardipee is Irish and Eastern Band Cherokee. Her research assistant, Mike O'Brien, is Assiniboine and Turtle Mountain Chippewa from Fort Peck, as well as a UM senior majoring in wildlife biology.

Gardipee said O'Brien's contribution to the bison project nearly equals her own. "He has been with me since day one," she said. O'Brien was funded by Project TRAIN -- Training American Indians in Environmental Biology -- a project of UM and Salish Kootenai College in Pablo.

"We just kind of say it takes crazy people like us to go out in the field and pick up poop from bison," she said, "but now we are getting some really important information regarding bison ecology out of it."

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Materials provided by University Of Montana. Note: Content may be edited for style and length.

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University Of Montana. "Distinct Bison Herds Roam Yellowstone." ScienceDaily. ScienceDaily, 29 January 2007. <>.
University Of Montana. (2007, January 29). Distinct Bison Herds Roam Yellowstone. ScienceDaily. Retrieved June 17, 2024 from
University Of Montana. "Distinct Bison Herds Roam Yellowstone." ScienceDaily. (accessed June 17, 2024).

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