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Abstract |
Cyclic population fluctuations are common in boreal and Arctic species but the
causes of these cycles are still debated today. Among these species, lemmings are Arctic
rodents that live and reproduce under the snow and whose large cyclical population fluctuations
in the high Arctic impact the whole tundra food web. We explore, using lemming
population data and snow modeling, whether the hardness of the basal layer of the snowpack,
determined by rain-on-snow events (ROS) and wind storms in autumn, can affect
brown lemming population dynamics in the Canadian high Arctic. Using a 7-year dataset
collected on Bylot Island, Nunavut, Canada over the period 2003–2014, we demonstrate
that liquid water input to snow is strongly inversely related with winter population growth
(R2 ≥ 0.62) and to a lesser extent to lemming summer densities and winter nest densities
(R2 = 0.29–0.39). ROS in autumn can therefore influence the amplitude of brown lemming
population fluctuations. Increase in ROS events with climate warming should strongly
impact the populations of lemmings and consequently those of the many predators that
depend upon them. Snow conditions may be a key factor influencing the cyclic dynamics
of Arctic animal populations. |
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