How climate impacts the composition of wolf killed-elk in northern Yellowstone National Park

1. While the functional response of predators is commonly measured, recent work has revealed that the age and sex composition of prey killed is often a better predictor of prey population dynamics because the reproductive value of adult females is usually higher than that of males or juveniles.

2. Climate is often an important mediating factor in determining the composition of predator kills, but we currently lack a mechanistic understanding of how the multiple facets of climate interact with prey abundance and demography to influence the composition of predator kills.

3. Over 20 winters, we monitored 17 wolf packs in Yellowstone National Park and recorded the sex, age, and nutritional condition of kills of their dominant prey – elk – in both early and late winter periods when elk are in relatively good and relatively poor condition, respectively.

4. Nutritional condition (as indicated by percent marrow fat) of wolf-killed elk varied markedly with summer plant productivity, sno...

1. 尽管捕食者功能响应（functional response）的相关测量已较为普遍，但近期研究表明，被捕猎猎物的年龄与性别组成往往能更精准地预测猎物种群动态，究其原因在于成年雌性个体的繁殖价值通常高于雄性或幼体。
2. 气候通常是调控捕食者猎杀猎物组成的关键中介因子，但目前学界尚缺乏机制性认知，难以阐明气候的多维度特征如何与猎物丰度及种群统计特征相互作用，进而影响捕食者的猎杀猎物组成。
3. 在长达20余年的冬季监测周期内，我们对黄石国家公园（Yellowstone National Park）内的17个狼群开展了跟踪调查，记录了其优势猎物——马鹿（elk）——被猎杀个体的性别、年龄与营养状况；监测时段覆盖冬初与冬末两个时期，这两个时期的马鹿身体状况分别处于相对优良与相对较差的状态。
4. 被狼群猎杀的马鹿的营养状况（以骨髓脂肪百分比为表征指标）会随夏季植物生产力呈现显著差异，雪[原文此处未完整呈现]