Department of Ecoscience and Arctic Research Centre, Aarhus University, Roskilde, Denmark.
Department of Biology, University of Copenhagen, Copenhagen Ø, Denmark.
Rapid Commun Mass Spectrom. 2023 Mar 30;37(6):e9470. doi: 10.1002/rcm.9470.
Analysis of stable isotopes in tissue and excreta may provide information about animal diets and their nutritional state. As body condition may have a major influence on reproduction, linking stable isotope values to animal demographic rates may help unravel the drivers behind animal population dynamics.
We performed sequential analysis of δ N values in guard hair from 21 muskoxen (Ovibos moschatus) from Zackenberg in high arctic Greenland. We were able to reconstruct the dietary history for the population over a 5-year period with contrasting environmental conditions. We examined the linkage between guard hair δ N values in 12 three-month periods and muskox calf recruitment to detect critical periods for muskox reproduction. Finally, we conducted similar analyses of the correlation between environmental conditions (snow depth and air temperature) and calf recruitment.
δ N values exhibited a clear seasonal pattern with high levels in summer and low levels in winter. However, large inter-annual variation was found in winter values, suggesting varying levels of catabolism depending on snow conditions. In particular δ N values during January-March were linked to muskox recruitment rates, with higher values coinciding with lower calf recruitment. δ N values were a better predictor of muskox recruitment rates than environmental conditions.
Although environmental conditions may ultimately determine the dietary δ N signal in muskox guard hairs, muskox calf recruitment was more strongly correlated with δ N values than ambient snow and temperature. The period January-March, corresponding to late gestation, appears particularly critical for muskox reproduction.
分析组织和排泄物中的稳定同位素可以提供有关动物饮食及其营养状况的信息。由于身体状况可能对繁殖有重大影响，将稳定同位素值与动物人口统计数据联系起来可能有助于揭示动物种群动态背后的驱动因素。
我们对来自格陵兰北极 Zackenberg 的 21 只麝牛（Ovibos moschatus）的护毛中的 δN 值进行了顺序分析。我们能够在 5 年的时间内重建该种群的饮食史，该时期的环境条件截然不同。我们检查了 12 个为期三个月的护毛 δN 值与麝牛小牛招募之间的联系，以检测麝牛繁殖的关键时期。最后，我们对环境条件（雪深和气温）与小牛招募之间的相关性进行了类似的分析。
δN 值表现出明显的季节性模式，夏季水平高，冬季水平低。然而，冬季值存在很大的年际变化，这表明根据雪况存在不同程度的分解代谢。特别是 1 月至 3 月的 δN 值与麝牛的招募率有关，较高的值与较低的小牛招募率相对应。δN 值是麝牛招募率的更好预测指标，而不是环境条件。
尽管环境条件最终可能决定麝牛护毛中的饮食 δN 信号，但麝牛小牛的招募与 δN 值的相关性强于环境雪温和温度。1 月至 3 月的时间段，对应于晚期妊娠，似乎对麝牛的繁殖特别关键。
