A fascinating new study has shed light on the mysterious population dynamics of the Canada lynx (Lynx canadensis) in Alaska’s interior, revealing a ‘travelling population wave’ that impacts their breeding, movements and survival.
The discovery – published in the Proceedings of the National Academy of Sciences – could play a crucial role in helping wildlife managers make smarter decisions about protecting this iconic predator of the boreal forest.
The concept of a 'travelling population wave' refers to the way animal populations rise and fall, rippling through a region like a wave, explains Derek Arnold, lead investigator of the study.
In the case of the Canada lynx, this cycle is closely tied to the fluctuating numbers of their main prey, the snowshoe hare, which goes through a boom-and-bust pattern every 10 to 12 years. When hare numbers increase, lynx thrive, but as soon as their prey declines due to food shortages, lynx populations follow suit – typically lagging a year or two behind.
Arnold and his team conducted their research between 2018 and 2022, right as the hare population was peaking. Their work tracked the reproduction, movements and survival of 143 lynx across five wildlife refuges – Tetlin, Yukon Flats, Kanuti and Koyukuk (all in Interior Alaska), as well as Gates of the Arctic National Park – with GPS collars providing valuable insight into how lynx respond to the prey population's decline.
The lynx’s response to the snowshoe hare collapse played out in three distinct phases, starting in the east and sweeping westward across the landscape – clear evidence of the travelling wave.
First, researchers observed a sharp drop in reproduction. When the study began, some dens contained up to eight kittens, but as the hare population dropped, the lynx’s ability to reproduce disappeared entirely by the end of the study.
Next, the lynx began to disperse. In search of better conditions, these agile predators left their territories, crossing mountain ranges and even rivers in their quest for food. One adventurous lynx travelled nearly 1,000 miles to the Alberta border, showing just how far they’ll go when resources dry up.
In the final stage, lynx survival rates plummeted. Interestingly, those that travelled eastward, against the population wave, had higher mortality rates, while those that went westward or stayed put fared better.
Arnold notes that while these findings align with what local trappers and hunters have long observed, the data offers concrete evidence and a broader view of the phenomenon. "We’ve known lynx and hares are linked by this 10- to 12-year cycle, but this study helps us see how it moves across the landscape," he says.
Understanding that this cycle typically sweeps from east to west makes lynx population trends more predictable. Wildlife managers can now make more informed, localised decisions about lynx conservation, rather than treating the entire state as one unit.
A key takeaway from the study is the importance of protected areas. Lynx that leave their home territories during population crashes often don’t survive, highlighting the role that refuges play in safeguarding these animals through tough times.
The study was published in the Proceedings of the National Academy of Sciences.
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