Species → Canada Lynx

Canada Lynx

Lynx canadensis

no reliable global estimate exists; populations considered secure in…
Extinction risk Least Concern
Predator-prey cycleBoreal forestSpecialist predatorArctic environment
Canada Lynx (Lynx canadensis)
Photo: Michael Zahra, Wikimedia Commons (CC BY-SA 3.0)

What if it disappeared?

Impact Major
Over 199 years

The number of lynx trapped tracked, with a slight lag, the highs and lows of the snowshoe hare in a cycle of about 9.6 years — a regularity that remained striking across two full centuries of records.

Documented
Detail

Elton, C. et Nicholson, M. (1942). The Ten-Year Cycle in Numbers of the Lynx in Canada. Journal of Animal Ecology, 11(2), 215–244.

A foundational study in population ecology, built from the fur sale records of the Hudson's Bay Company and other traders, covering up to 206 years depending on the region (regional detail for 1821-1934/1937). The lynx, a near-specialist predator of the snowshoe hare, sees its own numbers rise and fall in step with the hare's — one of the most studied datasets in all of animal ecology.

8 years (Yukon)

Excluding mammalian predators (including the lynx) from a plot doubled hare density compared to control plots; combining this exclusion with supplemental food pushed density up to 11 times that of control plots — experimental proof that predation, not just food, drives the cycle.

Documented
Detail

Krebs, C.J., Boutin, S., Boonstra, R. et al. (1995). Impact of Food and Predation on the Snowshoe Hare Cycle. Science, 269(5227), 1112–1115.

A large-scale factorial experiment conducted on one-square-kilometer plots in southwestern Yukon over eight years, manipulating both available food and mammalian predator access. The doubling of density achieved by excluding predators alone isolates the contribution of predation; the elevenfold factor obtained by combining both manipulations shows that food and predation act together, not one in the absence of the other.

By extrapolation

The lynx, a hare specialist, and the coyote, a generalist able to fall back on other prey, do not respond the same way to the troughs of the cycle — losing the lynx specifically could therefore dampen the cycle's amplitude without erasing it, rather than having the same effect as excluding all predators at once.

Extrapolated
Detail

Extrapolation à partir de O'Donoghue, Boutin, Krebs et al. (1998). Functional responses of coyotes and lynx to the snowshoe hare cycle. Ecology, 79(4), 1193–1208, qui compare les deux prédateurs sans mesurer l'effet du retrait du seul lynx.

The study shows that the lynx and the coyote, predators of comparable size, differ in their hunting behavior and their ability to catch replacement prey when hares become scarce — the coyote shifts its diet, the lynx much less so. This asymmetry suggests that the lynx's role in the cycle's trough is not interchangeable with the coyote's, but no experiment has isolated the effect of removing the lynx alone to confirm it.

What's missing to confirm it: No field experiment has excluded the lynx alone (leaving other predators in place) to directly measure the extent to which the hare cycle would persist without it specifically.

Over the long term

Hare browsing influences the regeneration of willow, birch and poplar in the boreal forest — but no study directly links a change in the lynx's role in the cycle to a measured change in forest composition.

Insufficient

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