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Snowshoe Hae Hypothesis

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Records from Hudson Bay Company post show a pattern of fluctuating numbers of snowshoe hare fur. Every ten years there appear to be a shortage of snowshoe hare fur, but then the number always rises. Following the cycle, it was noticed that the Canada lynx time lagged behind the snowshoe hare. Traded fur was used as a proxy to reflect the populations of snowshoe hares and Canada lynx. Additionally, not only is there a ten year cycle, but it is also synchronized with most of Canada. Krebs et al. (2001) discusses the mechanism of this 10-year cycle and synchrony, and explains why the Lotka-Volterra predator-prey model is only half correct for this system. The authors developed three hypotheses to answer the question of what drives the ten year cycle. They proposed food quantity and quality, social …show more content…

(2001) determined that predation is the main factor driving the snowshoe hare cycle. First they identified that 81% of the radio tagged snowshoe hares died due to predation. Then they conducted experiments to further test their hypothesis. They had a control and two treatments (predator exclosure and food, and predator exclosure). Mammalian predators were excluded, however avian predators were able to still prey on the hares within the exclosures. This was due to avian predators avoiding the fish netting in the trees.
During the decay phase of the cycle the snowshoe hare population in the exclosures didn’t decrease as dramatically as it did outside of the exclosures. There was a higher survival rate of snowshoe hares within the exclosures. Also, the exclosure with added food had a higher survival rate than the exclosure without added food. This experiment produces several results. Firstly, predation is the direct factor driving the snowshoe hare cycle. Secondly, the cycle is more driven by mammalian predation, rather than avian predation. Thirdly, both predation and food supply are important factors in determining the

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