Canada lynx (Lynx canadensis) and snowshoe hares (Lepus americanus) form a keystone predator–prey cycle that has large impacts on the North American boreal forest vertebrate community. Snowshoe hares and lynx are both well-suited for snowy winters, but climate change-associated shifts in snow conditions could lower hare survival and alter cyclic dynamics. Using detailed monitoring of snowshoe hare cause-specific mortality, behaviour and prevailing weather, we demonstrate that hare mortality risk is strongly influenced by variation in snow conditions. Although predation risk from lynx was largely unaffected by snow conditions, coyote (Canis latrans) predation increased in shallow snow. Maximum snow depth in our study area has decreased 33% over the last two decades and predictions based on prolonged shallow snow indicate that future hare survival could resemble that seen during population declines. Our results indicate that climate change could disrupt cyclic dynamics in the boreal forest.

加拿大天猫（Lynx canadensis）和雪兔（Lepus americanus）形成了梯形捕食者－被捕食者循环，​​对北美北方森林脊椎动物群落产生了重大影响。雪鞋野兔和山猫都非常适合下雪的冬天，但是与气候变化相关的雪况变化可能会降低野兔的生存率并改变周期性。通过对雪鞋野兔特定原因的死亡率，行为和当前天气的详细监控，我们证明了野兔死亡率风险受雪况变化的强烈影响。尽管天猫的捕食风险在很大程度上不受降雪条件的影响，但土狼（Canis latrans）在浅雪中的捕食增加。在过去的二十年中，我们研究区域的最大积雪深度减少了33％，基于长期浅雪的预测表明，未来的野兔生存可能类似于人口下降期间的生存。我们的结果表明，气候变化可能会破坏北方森林的循环动力。