Abstract Peary caribou (Rangifer tarandus pearyi) is listed as Endangered under Canada's Species at Risk Act. Studying rare and endangered species can be particularly challenging due to the constraints posed by incomplete datasets owing to poor weather conditions, lack of technology, organizational deficiencies, and high survey costs in remote areas. A defensible way to remedy data gaps and thus improve the robustness of any given modelling exercise is through imputation schemes, which are typically selected on the basis of missing data patterns. In this study, we develop a regression-based imputation method aiming to identify the linkages among available population records in time and space. One of the fundamental assumptions of our imputation model is that there is a subset of primary islands that act as the core areas from where the Peary caribou populations migrate to secondary or satellite islands. Specifically, we delineated six distinct geographic clusters (Banks, Axel Heiberg, Bathurst, Boothia, Melville and Mackenzie King) across the Canadian Arctic Archipelago, and within each cluster Peary caribou seasonal inter-island movements take place in any given year. Parameterized with Bayesian inference techniques, our imputation modelling strategy has a flexible structure that can accommodate non-monotonic spatiotemporal patterns, and was thus able to capture more than 65% of the variability in our dataset. The two islands (Banks and Northwest Victoria) of the Banks island complex exhibited an average decline rate of 6% per year over the past four decades, which collectively reflects the dramatic population decrease from the early 1970s until the late 1990s, as well as the distinct recovery after the early 2000s. Similar “wax-and-wane” cycles characterize the Peary caribou population patterns on Melville and Bathurst island complexes. Our analysis provides evidence of positive rate of change of the population trends on Axel Heiberg and Ellesmere Islands, which likely stems from pockets on those islands, where favorable climatic/geomorphological conditions, and rich vegetation prevail. In stark contrast, overharvesting, higher predation, adverse climatic conditions, and human-induced forage shortage have led to a dramatic decline, nearing their extirpation, on the Boothia island complex.

中文翻译：

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连接濒危物种数据库中的点：缺失 Peary caribou (Rangifer tarandus pearyi) 种群数据的贝叶斯分层插补策略

摘要 Peary caribou (Rangifer tarandus pearyi) 被加拿大的《濒危物种法》列为濒危物种。由于恶劣的天气条件、缺乏技术、组织缺陷和偏远地区的高调查成本，不完整的数据集带来了限制，因此研究稀有和濒危物种可能特别具有挑战性。弥补数据差距并因此提高任何给定建模练习的稳健性的一种防御性方法是通过插补方案，通常根据缺失的数据模式进行选择。在这项研究中，我们开发了一种基于回归的插补方法，旨在确定可用人口记录在时间和空间上的联系。我们的插补模型的一个基本假设是，有一部分主要岛屿充当 Peary 驯鹿种群迁移到次要或卫星岛屿的核心区域。具体来说，我们划定了横跨加拿大北极群岛的六个不同的地理集群（Banks、Axel Heiberg、Bathurst、Boothia、Melville 和 Mackenzie King），并且在每个集群内，皮里驯鹿在任何给定年份都会发生季节性的岛屿间运动。使用贝叶斯推理技术参数化，我们的插补建模策略具有灵活的结构，可以适应非单调时空模式，因此能够捕获我们数据集中超过 65% 的可变性。班克斯岛综合体的两个岛屿（班克斯岛和维多利亚西北部）在过去 40 年中平均每年下降 6%，这共同反映了从 1970 年代初到 1990 年代后期人口急剧减少，以及2000 年代初后明显复苏。梅尔维尔和巴瑟斯特岛复合体上的皮里驯鹿种群模式具有类似的“盛衰”循环特征。我们的分析提供了 Axel Heiberg 和 Ellesmere 群岛人口趋势正变化率的证据，这可能源于这些岛屿上的口袋，那里有有利的气候/地貌条件和丰富的植被。与此形成鲜明对比的是，过度捕捞、更高的捕食率、不利的气候条件以及人为造成的草料短缺导致了急剧下降，