Population dynamics of a northern-adapted mammal: disentangling the influence of predation and climate change.
Population dynamics of a northern-adapted mammal: disentangling the influence of predation and climate change.
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适应北方的哺乳动物的种群动态：理清捕食和气候变化的影响。
作者：
J. W. Pokallus;J. Pauli
群落结构和种间相互作用特别容易受到迅速变化的气候状况的影响。最近的气候和脊椎动物群落组合的变化创造了一个独特的机会来研究两种动态力量对种群调节的影响。我们研究了温暖的冬季条件和重建以前灭绝的捕食者，渔民（Martes pennanti），在北方适应的哺乳动物，豪猪（Erethizon dorsatum），沿着他们的南部范围边界的监管机制的影响。使用长期（17年）捕获-再捕获数据集，我们（1）量化了气候变化和渔民捕食增加对成年豪猪在其区域南部终点生存的影响，（2）评估了补充（3）模拟了捕食和冬季条件对豪猪种群统计学和种群增长率（λ）的相对重要性。严酷的冬季和丰富的捕食者相互作用的协同作用，减少成人生存高达44%，而扩大捕食者种群导致豪猪之间的近生殖失败。不断增加的捕食压力，在这个社区模块的中断，更频繁的极端冬季天气事件导致预测灭绝在50年内，而在没有捕食者，人口是可行的。我们的研究结果提供了一个机制的理解背后的分布变化引起的气候变化，并可能是广泛相关的预测未来的分布变化，在其他适应北方的哺乳动物物种。
Community structure and interspecific interactions are particularly vulnerable to rapidly changing climatic regimes. Recent changes in both climate and vertebrate community assemblages have created a unique opportunity to examine the impacts of two dynamic forces on population regulation. We examined the effects of warming winter conditions and the reestablishment of a previously extirpated predator, the fisher (Martes pennanti), on regulatory mechanisms in a northern-adapted mammal, the porcupine (Erethizon dorsatum), along their southern range boundary. Using a long-term (17-year) capture-recapture data set, we (1) quantified the impacts of climate change and increased fisher predation on the survival of adult porcupines at their regional southern terminus, (2) assessed recruitment (via both adult fecundity and juvenile survival) of porcupines, and (3) modeled the relative importance of predation and winter conditions on the demography and population growth rate (λ). Severe winters and abundant predators interacted synergistically to reduce adult survivorship by as much as 44%, while expanding predator populations led to near reproductive failure among porcupines. Increasing predatory pressure, disruptions in this community module, and more frequent extreme winter weather events led to predicted extirpation within 50 years, whereas in the absence of predators, the population was viable. Our results provide a mechanistic understanding behind distributional shifts resulting from climate change and may be broadly relevant for predicting future distributional shifts in other northern-adapted mammalian species.