Disentangling direct and indirect determinants of the duration of maternal care in brown bears: environmental context matters

The duration of maternal care, an important life history trait affecting population dynamics, varies greatly within species. Yet, our understanding of its predictors is limited, mostly correlative, and subject to misinterpretations, due to difficulties to disentangle the role of maternal- and offspring-related characteristics.

We conducted path analysis on a dataset including 217 brown bear litters captured over a 29-year period in two populations in Sweden (“North” and “South”) facing contrasting environmental conditions to identify and quantify the causes of variation in the duration of maternal care (1.5 years or 5 years).

Methods
The data presented in this dataset were collected as part of the Scandinavian Brown Bear Research Project, in two study populations of brown bears in Sweden: the North and the South. It includes data on the duration of maternal care as well as its potential determinants (maternal age, maternal mass, maternal parity status, litter size, offspring mass, litter sex ratio). This dataset is a cleaned version (e.g. exludes missing informations) that was used to conduct the analyses presented in the paper Van de Walle et al. 2020 Disentangling direct and indirect determinants of the duration of maternal care in brown bears: environmental context matters.

母体照料时长（duration of maternal care）是影响种群动态（population dynamics）的重要生活史特征（life history trait），在同一物种种内存在显著差异。然而，由于难以厘清母体相关与后代相关特征各自的作用，目前学界对其影响因子（predictors）的认知仍较为有限，相关研究多为相关性分析且易存在解读偏差。

本研究针对环境条件迥异的瑞典南北两处棕熊（brown bear）种群开展路径分析（path analysis），所用数据集涵盖29年间捕获的217窝棕熊幼崽，旨在明确并量化母体照料时长（1.5年或5年）的变异成因。

方法
本数据集的数据采集自斯堪的纳维亚棕熊研究项目（Scandinavian Brown Bear Research Project），涉及瑞典南北两处棕熊研究种群。数据集包含母体照料时长及其潜在影响因子的数据，具体包括母体年龄、母体体重、母体产次（maternal parity status）、窝仔数（litter size）、幼崽体重（offspring mass）以及窝性比（litter sex ratio）。该数据集为经清洗后的版本（例如剔除了缺失数据），曾用于Van de Walle等人2020年发表的论文《Disentangling direct and indirect determinants of the duration of maternal care in brown bears: environmental context matters》中的分析工作。