Comment on Krüger (2023): Decreasing Trends of Chinstrap Penguin Breeding Colonies in a Region of Major and Ongoing Rapid Environmental Changes Suggest Population Level Vulnerability. Diversity 2023, 15, 327

Data and analyis scripts for: Comment on Krüger (2023): Decreasing Trends of Chinstrap Penguin Breeding Colonies in a Region of Major and Ongoing Rapid Environmental Changes Suggest Population Level Vulnerability. Diversity 2023, 15, 327 W. Chris Oosthuizen, Murray Christian, Mzabalazo Ngwenya Centre for Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Cape Town, 7701, South Africa Abstract Historical data on chinstrap penguin (Pygoscelis antarctica) breeding population sizes are sparse and sometimes highly uncertain, making it hard to estimate true population trajectories. Yet, information on population trends is desirable as changes in population size can help inform conservation assessments. Krüger (2023) (Diversity 2023, 15, 327) used chinstrap penguin nest count data to predict breeding colony size trends between 1960 and 2020, to estimate whether the level of population change within three generations exceeded IUCN Red List Criteria for "Vulnerable" populations. Chinstrap penguin population trends are an important research topic, but we caution that Krüger (2023)’s statistical analyses (intended to form the foundation for drawing valid, evidence-based inferences from sparse data) contain fundamental errors that invalidate that paper's findings. We discuss these oversights to help others detect and avoid some of the pitfalls associated with estimating population trends with mixed models. While we do not address all challenges, we also show through reanalysis that improved statistical modelling can yield better predictions of chinstrap penguin population trends, at least within the range of observed data. This case study highlights (1) the profound influence that seemingly minor differences in modelling procedures (both unintentional errors and other decisions) can have on predictions of population trends, and (2) the substantial inherent uncertainty in population trend predictions derived from sparse, heterogenous data. Keywords: Antarctic Peninsula, IUCN red list criteria, Mapping Application for Penguin Populations and Projected Dynamics (MAPPPD), population assessment, population trend, Pygoscelis antarctica, reproducible research本数据集与分析脚本配套的研究为：对Krüger（2023）的评论：《在持续快速发生重大环境变化的区域中，纹颊企鹅繁殖种群的下降趋势预示种群级脆弱性》，发表于*Diversity* 2023, 15, 327。 作者：W. Chris Oosthuizen、Murray Christian、Mzabalazo Ngwenya 南非开普敦大学统计科学系生态、环境与保护统计中心，开普敦 7701 摘要： 纹颊企鹅（Chinstrap Penguin，学名*Pygoscelis antarctica*）的繁殖种群规模历史数据稀缺且部分存在高度不确定性，因此难以准确估计其真实种群动态轨迹。然而种群趋势信息仍是亟需的，因为种群规模变化可为保护评估提供依据。Krüger（2023）（发表于*Diversity* 2023, 15, 327）利用纹颊企鹅的巢计数数据，预测了1960年至2020年间的繁殖种群规模趋势，并以此评估三代以内的种群变化幅度是否达到国际自然保护联盟（IUCN）红色名录中“易危（Vulnerable）”种群的标准。 纹颊企鹅种群趋势是重要的研究议题，但我们需指出，Krüger（2023）的统计分析——其初衷是为从稀缺数据中得出可靠且循证的推断奠定基础——存在根本性错误，导致该论文的研究结论不成立。我们在此讨论这些疏漏，以期帮助其他研究者识别并规避混合模型在种群趋势估计中可能存在的部分陷阱。尽管我们并未涵盖所有挑战，但通过重新分析我们也证明，优化后的统计模型能够更准确地预测纹颊企鹅的种群趋势，至少在观测数据的范围内是如此。本案例研究揭示了两点：（1）建模流程中看似细微的差异（包括无意的错误与其他决策选择）会对种群趋势预测产生深远影响；（2）基于稀缺且异质性数据得出的种群趋势预测，本身存在显著的固有不确定性。 关键词：南极半岛，国际自然保护联盟红色名录标准，企鹅种群与预测动态绘图应用（Mapping Application for Penguin Populations and Projected Dynamics，MAPPPD），种群评估，种群趋势，*Pygoscelis antarctica*，可重复研究