‘Landscape of Fear’: Yellowstone Not So Scary After All

The researchers revisited data from 27 GPS radio-collared elk that had been collected in the early years after the reintroduction. (Photo credit: Michel Kohl)
The researchers revisited data from 27 GPS radio-collared elk that had been collected in the early years after the reintroduction. (Photo credit: Michel Kohl)

After wolves were reintroduced to Yellowstone National Park in the mid-1990s, some scientists thought the large predator reestablished a “landscape of fear” that caused elk, the wolf’s main prey, to avoid risky places where wolves killed them. This fueled the emerging idea that predators affect prey populations and ecosystems not only by eating prey animals, but by scaring them too.

Wolves in Yellowstone spend much of the day and night resting, and elk use these times to safely forage in habitats where wolves might catch them. Utah State University scientists report findings in an Early View online article of "Ecological Monographs." (Photo credit: Daniel Stahler/NPS)

Wolves in Yellowstone spend much of the day and night resting, and elk use these times to safely forage in habitats where wolves might catch them. Utah State University scientists report findings in an Early View online article of ‘Ecological Monographs.’ (Photo credit: Daniel Stahler / NPS)

However, according to findings from Utah State University ecologists Michel Kohl and Dan MacNulty, Yellowstone’s “landscape of fear” is not as scary as first thought. Kohl, who completed a doctoral degree at USU in 2018 and is the lead author of the paper, said:

The findings were published in an online article in Ecological Monographs and will appear in a future print edition of the Ecological Society of America publication. Kohl, the lead author, along with MacNulty, conducted the research, supported in part by the National Science Foundation, with colleagues Daniel Stahler, Douglas Smith, and P.J. White of the U.S. National Park Service, Matthew Metz of the University of Montana, James Forester of the University of Minnesota, Matthew Kauffman of the University of Wyoming, and Nathan Varley of the University of Alberta.

Utah State University scientists say Yellowstone wolves hunt mostly during morning and evening, allowing elk relief from predation at night and mid-day. In an Early View online article of "Ecological Monographs," the researchers discuss how elk use these lulls in wolf hunting activity to maintain access to important habitats. (Photo credit: Daniel Stahler/NPS)

Utah State University scientists say Yellowstone wolves hunt mostly during morning and evening, allowing elk relief from predation at night and midday. In an Early View online article of ‘Ecological Monographs,’ the researchers discuss how elk use these lulls in wolf hunting activity to maintain access to important habitats. (Photo credit: Daniel Stahler / NPS)

The researchers revisited data from 27 GPS radio-collared elk that had been collected in the early years after the reintroduction, 2001-2004, but never fully analyzed. These collars recorded the location of each elk every 4-6 hours. This was the first time GPS technology had been used to track Yellowstone elk, and no one imagined that elk might sync their habitat use to the wolf’s 24-hour schedule.

Utah State University scientists have shown that a 'landscape of fear' does not keep Yellowstone elk from using risky habitats where wolves kill them. In an Early View online article of "Ecological Monographs," the researchers discuss how elk use nightly lulls in wolf activity to safely access dangerous areas. (Photo credit: Chad Wildermuth)

Utah State University scientists have shown that a ‘landscape of fear’ does not keep Yellowstone elk from using risky habitats where wolves kill them. In an Early View online article of ‘Ecological Monographs,’ the researchers discuss how elk use nightly lulls in wolf activity to safely access dangerous areas. (Photo credit: Chad Wildermuth)

Little was known about this schedule until researchers first equipped wolves with GPS collars in 2004. MacNulty, a veteran Yellowstone wolf researcher and associate professor in USU’s Department of Wildland Resources and the USU Ecology Center, said:

Kohl used the GPS data to quantify the 24-hour schedule of wolves, and he compared how elk use of risky places — sites where wolves killed elk — differed between periods of high and low wolf activity, he said:

Elk feed on willow plants during a lull in wolf activity in northern Yellowstone National Park. In an Early View online article of "Ecological Monographs," Utah State University scientists report that elk maintain access to risky habitats by using them at night when wolves are resting. (Photo credit: Michel Kohl)

Elk feed on willow plants during a lull in wolf activity in northern Yellowstone National Park. In an Early View online article of ‘Ecological Monographs,’ Utah State University scientists report that elk maintain access to risky habitats by using them at night when wolves are resting. (Photo credit: Michel Kohl)

The ability of elk to regularly use risky places during wolf downtimes has implications for understanding the impact of wolves on elk and the ecosystem at large, MacNulty said:

This conclusion runs counter to popular views about the ecological importance of fear in Yellowstone and elsewhere, Kohl said:

Provided by: Utah State University [Note: Materials may be edited for content and length.]

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