Svalbard reindeer winter diets (1995–2012) dataset

Arctic ecosystems are changing dramatically with warmer and wetter conditions resulting in complex interactions between herbivores and their forage. We investigated how Svalbard reindeer (Rangifer tarandus platyrhynchus) modify their late winter diets in response to long-term trends and interannual variation in forage availability and accessibility. By reconstructing their diets and foraging niches over a 17-year period (1995–2012) using serum δ13C and δ15N values, we found strong support for a temporal increase in the proportions of graminoids in the diets with a concurrent decline in the contributions of mosses. This dietary shift corresponds with graminoid abundance increases in the region and was associated with increases in population density, warmer summer temperatures and more frequent rain-on-snow (ROS) in winter. In addition, the variance in isotopic niche positions, breadths and overlaps also supported a temporal shift in the foraging niche and a dietary response to extreme RO...北极生态系统正经历剧烈变化，气候暖湿化使得植食动物与其取食植被间的相互作用愈发复杂。本研究探讨了斯瓦尔巴群岛驯鹿（Rangifer tarandus platyrhynchus）如何响应取食资源可获得性与可及性的长期趋势及年际变化，调整其晚冬季采食食谱。本研究借助血清碳稳定同位素δ¹³C与氮稳定同位素δ¹⁵N值，重建了1995至2012年共计17年的种群食谱与觅食生态位序列，结果发现其食谱中禾草类植物占比随时间显著提升，苔藓类的贡献则同步下降，该结论得到了强有力的支持。该食谱转变与该区域禾草类植物丰度的增加相契合，同时与种群密度上升、夏季气温升高以及冬季雪雨事件（ROS）发生频次增加存在显著关联。此外，同位素生态位的位置、宽度及重叠度的方差变化，同样支持了觅食生态位的时间推移特征，以及种群食谱对极端雪雨事件的响应。