Seasonal demography of a cyclic lemming population in the Canadian Arctic
Seasonal demography of a cyclic lemming population in the Canadian Arctic
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DOI：
10.1111/1365-2656.12385
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发表时间：
2015-09-01
影响因子：
4.8
通讯作者：
Berteaux, Dominique
中科院分区：
文献类型：
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作者：
Fauteux, Dominique;Gauthier, Gilles;Berteaux, Dominique
动物种群周期性波动的原因在生态学中仍然是一个有争议的话题。食物限制和捕食是解释北方小型哺乳动物种群动态的两个主要假说。我们记录了与旅鼠种群变化相关的下降阶段和人口统计参数（生存和繁殖）的季节性时间，使我们能够评估这两个假设的一些预测。我们研究了棕色旅鼠（Lemmus trimucronatus），一个物种显示3至4年的人口周期，在加拿大北极地区，结合捕获标记再捕获分析夏季活诱捕监测冬季巢超过10年的时间。我们还研究了一些天气变量对生存的影响。我们发现，在夏季和冬季之间出现一个高峰后，人口下降，而不是在冬季。在夏季，人口增长是由生存的变化，但不是在繁殖力或比例的青少年，而在冬季人口增长是由夏末和冬季繁殖的变化。我们没有发现直接的密度依赖于夏季人口参数的证据，虽然我们的分析受到限制的数据在低阶段。然而，体重在高峰年份最高。天气的影响，仅在初夏时，旅鼠的生存呈正相关，积雪深度在融化的发病，但负相关的降雨量。研究结果表明，旅鼠夏秋两季的高死亡率导致旅鼠种群数量下降，表明捕食行为足以导致旅鼠种群崩溃，而冬季的高繁殖力则是导致旅鼠种群崩溃的主要因素。积雪深度和初夏生存之间的正相关可能是由于雪对捕食者提供的保护性覆盖。目前还不清楚为什么在低阶段繁殖率仍然很低。
The causes of cyclical fluctuations in animal populations remain a controversial topic in ecology. Food limitation and predation are two leading hypotheses to explain small mammal population dynamics in northern environments. We documented the seasonal timing of the decline phases and demographic parameters (survival and reproduction) associated with population changes in lemmings, allowing us to evaluate some predictions from these two hypotheses. We studied the demography of brown lemmings (Lemmus trimucronatus), a species showing 3- to 4-year population cycles in the Canadian Arctic, by combining capture-mark-recapture analysis of summer live-trapping with monitoring of winter nests over a 10-year period. We also examined the effects of some weather variables on survival. We found that population declines after a peak occurred between the summer and winter period and not during the winter. During the summer, population growth was driven by change in survival, but not in fecundity or proportion of juveniles, whereas in winter population growth was driven by changes in late summer and winter reproduction. We did not find evidence for direct density dependence on summer demographic parameters, though our analysis was constrained by the paucity of data during the low phase. Body mass, however, was highest in peak years. Weather effects were detected only in early summer when lemming survival was positively related to snow depth at the onset of melt but negatively related to rainfall. Our results show that high mortality causes population declines of lemmings during summer and fall, which suggests that predation is sufficient to cause population crashes, whereas high winter fecundity is the primary factor leading to population irruptions. The positive association between snow depth and early summer survival may be due to the protective cover offered by snow against predators. It is still unclear why reproduction remains low during the low phase.