Vital rates of large herbivores normally respond to increased resource limitation by following a progressive sequence of effects on life‐history characteristics from survival of young, age at first reproduction, reproduction of adults, to adult survival. Expected changes in life‐history characteristics, however, should operate through changes in nutritional condition, which is the integrator of nutritional intake and demands represented primarily by the deposition and catabolism of body fat. Elucidating seasonal patterns of nutritional condition and its relative influence on individual and population performance should improve our understanding of life‐history strategies and population regulation of ungulates, provide insight into the capacity of available habitat to support population growth, and allow assessment of the underlying consequences of mortality on population dynamics. We acquired longitudinal data on individual female mule deer (Odocoileus hemionus), and linked those data with environmental and population characteristics. Our goal was to provide a nutritional basis for understanding life‐history strategies of these large mammals, and to aid in the conservation and management of large herbivores in general. We studied a migratory population of mule deer that overwintered in Round Valley on the east side of the Sierra Nevada, California, USA, and was subject to a highly variable climate and predation from a suite of large carnivores. We intensively monitored nutritional and life‐history characteristics of this population during 1997–2009 as it recovered from a population crash, which occurred during 1985–1991. Deer in Round Valley migrated to high‐elevation summer ranges on both sides of the crest of the Sierra Nevada (Sierra crest), where a rain shadow resulted in a mesic and more forested range on the west side compared with xeric conditions east of the Sierra crest. Average survival of neonatal mule deer to 140 days of age during 2006–2008 was 0.33 (SE = 0.091), but was lower for neonates on the west side (0.13, SE = 0.092) compared with those on the east side (0.44, SE = 0.11) of the Sierra crest. Birth mass and nutritional condition of mothers had a positive effect on survival of young; however, those effects were evident only for neonates born east of the crest where predation pressure was less intense compared with the west side. Black bear (Ursus americanus) predation was the main cause of mortality for west‐side young (mortality rate = 0.63, SE = 0.97) compared with canid and felid predation for east‐side young (0.29, SE = 0.076). Mean autumn recruitment of young during 1997–2008 was lower for females on the west side (0.42, SE = 0.037) than for females on the east side (0.70, SE = 0.041) of the crest, and was affected positively by March ingesta‐free body fat (IFBFat) of individual females. At the level of the population, ratios of young‐to‐adult females (1991–2009) were highly variable and strongly related to March IFBFat of adult females during the current and preceding year. Reproduction by yearling females was sensitive to per capita availability of forage during summer (as 1‐yr‐old individuals), thereby influencing whether a sufficient body mass for ovulation was obtained. Litter size remained high (1.69, SE = 0.027) during the study, but was influenced positively by forage availability, negatively by summer temperature, and was greater for females that resided on the west side of the Sierra crest during summer than those on the east side. In contrast, pregnancy rates remained unchanged across years of study (0.98, SE = 0.005). Survival of prime‐age (2‐ to 9‐yr‐old) females was 0.90 (SE = 0.021) in summer, 0.94 (SE = 0.012) in winter, and 0.87 (SE = 0.025) annually. Although relatively stable across years, both winter and summer survival were influenced positively by the preceding April snowpack relative to the density of the population. Mean IFBFat of adult females was 7.2% (SE = 0.077) in March 1997–2009 and 9.7% (SE = 0.23) in November 2002–2008. Nutritional condition offered a mechanistic link between factors that influence resource limitation and population performance, because condition of adult females in autumn and late winter was sensitive to the nutritional history of individual animals as related to forage growth, population density, migratory tactic, reproductive costs, and nutritional carryover. Nutritional condition of adult females in March also was the most parsimonious predictor of finite rate of population growth (λ) during the forthcoming year. The relative magnitude of effect of nutritional condition on survival and reproduction was mostly in accordance with the predicted changes of vital rates in response to resource limitation for populations of large herbivores. Our results indicate that management and conservation of large herbivore populations could be improved by integrating indices of nutritional condition into current monitoring and research programs. We offer a method to estimate the proximity of a population to nutritional carrying capacity (NCC) that is based on nutritional status of the population relative to population performance (termed animal‐indicated NCC). The proximity of the population to animal‐indicated NCC represents the short‐term capacity of the environment to support population growth. A nutritional approach to monitor and manage populations offers a direct link to the capacity of the habitat, and reduces the need to estimate population abundance or set goals according to population size. We also propose that the consequences of mortality (degree of additive or compensatory mortality) on population dynamics can be assessed by comparing the estimated nutritional capacity for survival and recruitment of young to that measured empirically, because more young are produced than what the habitat can support when nutrition is limiting. Our approach is useful for quantifying effects of predation, and provides a basis for determining the efficacy of predator control to enhance ungulate populations. © 2014 The Wildlife Society.

中文翻译：

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of的生活史特征：营养在可变环境中的影响

大型草食动物的存活率通常通过遵循对生命历史特征的逐步影响顺序来应对资源的增加，这些影响从年轻人的存活，初次繁殖的年龄，成年的繁殖到成年的存活。但是，预期的生活史特征变化应通过营养状况的变化来进行，而营养状况的变化是营养摄入量和需求量的综合，其主要表现为体内脂肪的沉积和分解代谢。阐明营养状况的季节性模式及其对个体和种群表现的相对影响，应有助于我们了解生活史策略和有蹄类动物的种群调控，深入了解可利用的栖息地支持种群增长的能力，并可以评估死亡率对人口动态的潜在影响。我们获得了有关雌性m鹿的纵向数据（海豚），并将这些数据与环境和人口特征相关联。我们的目标是为了解这些大型哺乳动物的生命史策略提供营养基础，并总体上帮助大型草食动物的保护和管理。我们研究了USA鹿的迁徙种群，这些种群在美国加利福尼亚内华达山脉东侧的朗德河谷过冬，并受到气候变化的强烈影响和一系列大型食肉动物的捕食。随着人口从1985-1991年间的崩溃中恢复过来，我们在1997-2009年期间对其种群的营养和生活史特征进行了集中监测。圆谷的鹿迁移到内华达山脉（Sierra crest）顶峰两侧的高海拔夏季山脉，与塞拉利昂峰以东的干旱环境相比，那里的雨影在西侧造成了更陡峭的森林范围。在2006–2008年期间，新生儿ule鹿的平均存活时间为140天，为0.33（SE = 0.091），但在西侧（0.13，SE = 0.092）的新生儿比东侧（0.44，SE）低= 0.11）。母亲的出生质量和营养状况对年轻的生存有积极影响；但是，这些影响仅对出生在波峰以东的新生儿是明显的，与西侧相比，它们的掠食压力较弱。黑色的熊 （SE = 0.092），而塞拉利昂峰东侧（0.44，SE = 0.11）。母亲的出生质量和营养状况对年轻的生存有积极影响；但是，这些影响仅对出生在波峰以东的新生儿是明显的，与西侧相比，它们的掠食压力较弱。黑色的熊 （SE = 0.092），而塞拉利昂峰东侧（0.44，SE = 0.11）。母亲的出生质量和营养状况对年轻的生存有积极影响；但是，这些影响仅对出生在波峰以东的新生儿是明显的，与西侧相比，它们的掠食压力较弱。黑色的熊 （美洲熊）捕食是西侧幼犬死亡的主要原因（死亡率= 0.63，SE = 0.97），而东侧幼犬的犬齿和猫科动物的捕食（0.29，SE = 0.076）。1997-2008年期间，西侧的女性平均秋季招聘人数（0.42，SE = 0.037）要比东侧的女性（0.70，SE = 0.041）要低，并且受到三月摄食的积极影响。雌性个体的游离脂肪（IFBFat）。在人口水平上，年轻和成年女性的比例（1991-2009年）变化很大，并且与当年和上一年的成年雌性的3月IFBFat密切相关。一岁雌性的繁殖对夏季人均饲草的敏感性（以一岁个体为准），从而影响是否获得足够的体重来排卵。在研究过程中，凋落物的大小仍然很高（1.69，SE = 0.027），但受草料供应量的影响是积极的，夏季温度的影响是负面的，并且在夏季居住在塞拉利昂峰西侧的雌性比东部的雌性更大。侧。相反，在整个研究年中，怀孕率保持不变（0.98，SE = 0.005）。夏季（2至9岁）的成年女性存活率为0.90（SE = 0.021），冬季为0.94（SE = 0.012），每年为0.87（SE = 0.025）。尽管历年相对稳定，但相对于人口密度，冬季和夏季的生存都受到前四月积雪的积极影响。成年女性的平均IFBFat在1997–2009年3月为7.2％（SE = 0.077），在2002–2008年11月为9.7％（SE = 0.23）。营养条件在影响资源限制和种群表现的因素之间建立了机械联系，因为成年雌性在秋季和冬季末的状况对个体动物的营养史很敏感，因为它们与饲草生长，种群密度，迁徙策略，生殖成本，和营养残留。3月成年女性的营养状况也是来年有限人口增长率（λ）的最简约预测指标。营养条件对生存和繁殖的影响的相对大小主要是根据大型草食动物种群对资源的限制而对生命率的预期变化。我们的结果表明，通过将营养状况指标纳入当前的监测和研究计划，可以改善大型草食动物种群的管理和保护。我们提供了一种方法来估算人口与营养承载力（NCC）的接近度，该方法基于人口相对于人口绩效的营养状况（称为动物指示NCC）。人口接近动物指示的NCC代表环境支持人口增长的短期能力。一种营养方法来监视和管理种群，可直接与栖息地的能力联系起来，并减少了根据种群数量估算种群数量或设定目标的需求。我们还建议，可以通过将估计的年轻人生存和补充的营养能力与经验测得的营养能力进行比较，来评估死亡率（加性或代偿性死亡率的程度）对种群动态的影响，因为产生的年轻人比栖息地所能支持的更多当营养受到限制时。我们的方法可用于量化捕食的效果，并为确定捕食者控制提高有蹄类种群的功效提供基础。©2014野生动物协会。并为确定捕食者控制增加有蹄类动物种群的效力提供了基础。©2014野生动物协会。并为确定捕食者控制增加有蹄类动物种群的效力提供了基础。©2014野生动物协会。