Adelie penguin diet metadata, 1991-2024

The fundamental long-term objective of the seabird component of the Palmer LTER (PAL) has been to identify and understand the mechanistic processes that regulate the mean fitness (population growth rate) of regional penguin populations. Since the inception of PAL, Adélie penguin populations have effectively collapsed, gentoo penguin populations have increased dramatically and chinstrap penguin populations have remained relatively stable. These trends are spatially and temporally coherent with regional warming and decreasing sea ice duration. Adélie penguins are an ice-obligate polar species whose life history is intimately linked to the presence of sea ice, while chinstrap and gentoo penguins are ice-intolerant species whose life histories evolved in the sub-Antarctic, where sea ice is a less permanent feature of the marine ecosystem. The PAL study region includes five main islands on which Adélie penguin colonies have historically occurred, with each island containing a different number of spatially segregated sub-colonies. These colonies are censused to determine the total number of nests and chicks produced each year, and breeding success. Diet samples are acquired to understand diet composition (e.g., krill, fish) and krill length-frequencies. In general, krill constitute the most important component of the summer diets by mass of these three penguin species, but changes in PAL krill abundances have exhibited no long-term trends and thus far, have failed to explain the divergent patterns in penguin populations evident in our time series. Chick fledging masses are recorded as a cumulative measure of climate, weather, diet, and parental influences on chick health at the end of the breeding season. These data have provided valuable insights into the marine and terrestrial factors that influence Adélie penguin population fitness. No data were collected during the 2021-2022 season due to the Palmer Station pier rebuild.

帕尔马长期生态研究计划（Palmer LTER, PAL）的海鸟研究分支，其核心长期目标一直是识别并阐明调控区域企鹅种群平均适应度（种群增长率）的机制过程。自本计划启动以来，阿德利企鹅种群已出现实质性衰退，巴布亚企鹅种群数量大幅增长，而帽带企鹅种群则保持相对稳定。上述趋势在时空分布上与区域变暖、海冰持续时间缩短的特征高度一致。阿德利企鹅为依赖海冰的极地物种，其生活史与海冰的存在紧密关联；而帽带企鹅与巴布亚企鹅均为不耐海冰的物种，其生活史演化于亚南极海域——该海域中海冰并非海洋生态系统的永久性特征。PAL的研究区域涵盖历史上曾存在阿德利企鹅聚居地的5个主要岛屿，每个岛屿均分布有数量不等、空间上相互隔离的亚聚居群。研究人员会对这些聚居地开展普查，以统计每年的总筑巢数、雏鸟数量，并评估繁殖成功率。同时采集食性样本，以明确其饮食组成（如磷虾、鱼类）以及磷虾的体长频率分布。总体而言，按生物量占比计算，磷虾是这三种企鹅夏季饮食中最为关键的组成部分，但PAL监测到的磷虾种群丰度并未呈现长期变化趋势，因此至今仍无法解释时间序列中显现的企鹅种群分化模式。雏鸟离巢体重被作为繁殖季末期气候、天气、饮食条件以及亲代抚育对雏鸟健康影响的综合衡量指标进行记录。这些数据为探究影响阿德利企鹅种群适应度的海洋与陆地因素提供了宝贵的研究视角。由于帕尔马站码头重建工作，2021-2022年度未收集任何相关数据。