Study looks at elk predator
Census of Bitterroot mountain lions set
HAMILTON, Mont. – Mountain lions in the southern reaches of the Bitterroot Valley will soon be donating their DNA for the cause of science.
Most of the big cats involved in the new study won’t feel much more than a temporary sting to their thick hide as a result.
State and university biologists will fan out in the east and west forks of the Bitterroot River to take a census of mountain lion numbers in the same area where an intensive elk study is now under way.
They will be following experienced houndsmen who will use their dogs to tree the big cats.
Once treed, the lion will be shot with a hollow biopsy dart by a biologist, who will then collect the flesh for a DNA sample.
That information will be combined with additional DNA samples collected from scat and mountain lions harvested by hunters this winter to determine the number of lions and their distribution in the southern Bitterroot.
The need for that information has taken on new urgency following initial findings in the elk study, showing that mountain lions are the chief predator on elk calves in the area.
That has been a surprise for some involved in the three-year study, including Mark Hebblewhite, a University of Montana associate professor with a lead role in the elk research.
“Everyone was sure that this was going to be a wolf story,” Hebblewhite said. “Like many people, I’ve been surprised to see what we’ve learned so far.”
Researchers are about halfway through the three-year elk study.
They’ve documented that while black bears and wolves prey on elk calves during certain segments of the year, predation by mountain lions remains steady throughout the year.
In response to those findings, the state increased the quota for mountain lions in the Bitterroot this year and approved the one-year study on lion populations.
“We’ve found that lions play a very important role in elk calf survival in the Bitterroot,” Hebblewhite said. “We’re not ignoring wolves. We have some collared wolves that we’re tracking as well.
“We decided that if lions were this important to elk, we better understand the lion population here.”
Using research methods perfected in an extensive mountain lion study several years ago in the Garnet Mountains, the university tapped into about 100 computers to develop the monitoring techniques that will be employed in this study.
“It’s a one-shot deal,” Hebblewhite said. “We won’t have a second winter. We want to make sure we get it right.”
FWP research technician Ben Jimenez will be working directly with the houndsmen.
“The biopsy darts are less invasive than collaring and handling the animals,” Jimenez said. “We will be able to obtain a quality DNA sample and work with a lot of cats.”
The plan also calls for Jimenez and others to do backtracking to retrieve both hair and scat for additional DNA work.
More DNA will be gathered from lions killed by hunters.
“Between those different methods, we should be able to systematically obtain a good sample for the entire area,” Jimenez said. “From that, we will be able to put together a density estimate for that portion of the valley.”
The study will take place in hunting districts 250 and 270.
That information will be combined with results of the elk study to eventually create a report that will offer recommendations for future management of elk herds.
Those recommendations will be based on scientific evidence gathered as part of the study, Hebblewhite said.
At this point, no one can be sure where that might lead.
Researchers are just beginning to analyze vegetation and elk pellet samples gathered this past summer from a variety of sites.
The hope is that part of the research will provide some definitive scientific evidence on what kinds of vegetation provide the best nutrition for elk.
For instance, Hebblewhite said it appears that some of the best elk forage grows in places that have burned or been logged, but it would be wrong for anyone to make a sweeping generalization.
There are many variables to consider following a wildfire. A lot depends on the intensity and timing of the fire and whether it was old growth or a young forest that burned.
“There is sort of a truism that fire is good for elk habitat, but not all the time,” he said.
“Some of the higher-elevation fire doesn’t create great elk forage.”
This winter, some researchers will dissect elk pellets to analyze the animals’ diet.
“It’s really horrible work,” Hebblewhite said. “They actually look at what they have eaten by looking for different cell walls inside the pellet.”
The field work on the study is expected to be completed this next year. Hebblewhite expects that it will take another year for the research to be analyzed and wrapped into a written document.
He expects that there will be some more surprises along the way.
“There are always surprising things that happen when you collar an animal and follow it around,” Hebblewhite said.
“Science doesn’t necessarily make things easier. Hopefully, it does make them better.”