Study tracks wave of traveling Canadian lynx population

A new study led by researchers at the Institute of Arctic Biology at the University of Alaska Fairbanks provides compelling evidence that interior Alaska’s Canada lynx populations are experiencing a “shifting population wave” affecting their reproduction, movements and survival.

The results are published in the journal Proceedings of the National Academy of Sciences.

This discovery could help wildlife managers make more informed decisions when managing one of the boreal forest’s top predators.

A roving population wave is a common dynamic in biology, in which the number of animals in a habitat increases and decreases, moving across a region like a ripple.

Canada lynx populations in Alaska rise and fall in response to the 10- to 12-year boom-and-bust cycle of their primary prey: the snowshoe hare. During these cycles, hares reproduce rapidly, then their population collapses when food resources become scarce. The lynx population follows this cycle, usually with a delay of one to two years.

The study, which ran from 2018 to 2022, began at the height of this cycle, according to lead researcher Derek Arnold. Researchers tracked lynx reproduction, movements and survival as the population collapsed.

Between 2018 and 2022, biologists captured 143 lynx live in five interior Alaska national wildlife refuges – Tetlin, Yukon Flats, Kanuti and Koyukuk – as well as Gates of the Arctic National Park. The lynx were equipped with GPS collars, allowing satellites to track their movements across the landscape and produce an unprecedented dataset.

Arnold explained that the lynx responded to the collapse of the snowshoe hare population in three distinct stages, with changes originating from the east and moving west, clear evidence of a wave of shifting population .

• Reproductive decline: The first response was a sharp decline in reproduction. At the height of the cycle, when the study began, Arnold said researchers sometimes found as many as eight kittens in a single den. However, breeding in the easternmost study site initially ceased, and by the end of the study it had declined to zero in all study areas.
• Increased dispersal: After reproduction declined, the lynx began to disperse, leaving its original territory in search of better conditions. They traveled in all directions. “We thought there would be natural barriers to their movement, like the Brooks Range or Denali. But they crossed mountain ranges and swam across rivers,” Arnold said. “It shocked us.” A lynx traveled nearly 1,000 miles to the Alberta border.
• Decline in survival: In the final stages, survival rates fell. As lynx dispersed in all directions, those that moved east – against the tide – had significantly higher mortality rates than those that moved west or stayed within their territory. original.

Arnold said the study’s results won’t surprise anyone with real-world experience watching lynx and hares. “People like trappers have been observing this trend anecdotally for a long, long time. The data just provides supporting evidence and helps us see the bigger picture,” he said.

“We’ve known for a long time that hares and lynx operate on a 10- to 12-year cycle, but we don’t fully understand how this plays out across the landscape,” Arnold said. “It was unclear whether the cycle occurred simultaneously throughout the state or whether it occurred in isolated areas at different times.

“Knowing that the wave generally extends from east to west, lynx population trends are more predictable,” he said. “It will be easier for wildlife managers to make informed decisions now that we can predict how a population will behave on a more local scale, instead of just looking at the state as a whole.”

Another important point to remember is the importance of maintaining refuge populations. “Lynx that disperse during population declines generally don’t survive. Most of them don’t survive when they leave their home area,” Arnold said.

Other UAF authors include Greg Breed, Shawn Crimmins, and Knut Kielland.