Data from: Decline and recovery of a large carnivore: environmental change and long-term trends in an endangered brown bear population

Understanding what factors drive fluctuations in the abundance of endangered species is a difficult ecological problem but a major requirement to attain effective management and conservation success. The ecological traits of large mammals make this task even more complicated, calling for integrative approaches. We develop a framework combining individual-based modelling and statistical inference to assess alternative hypotheses on brown bear dynamics in the Cantabrian range (Iberian Peninsula). Models including the effect of environmental factors on mortality rates were able to reproduce three decades of variation in the number of females with cubs of the year (Fcoy), including the decline that put the population close to extinction in the mid-nineties, and the following increase in brown bear numbers. This external effect prevailed over density-dependent mechanisms (sexually selected infanticide and female reproductive suppression), with a major impact of climate driven changes in resource availability and a secondary role of changes in human pressure. Predicted changes in population structure revealed a nonlinear relationship between total abundance and the number of Fcoy, highlighting the risk of simple projections based on indirect abundance indices. This study demonstrates the advantages of integrative, mechanistic approaches and provides a widely applicable framework to improve our understanding of wildlife dynamics.

厘清驱动濒危物种种群数量波动的影响因子，既是生态学领域的核心难题，亦是实现高效野生动物管理与保护成效的必要前提。大型哺乳动物的生态特征进一步加剧了该研究的复杂度，因此亟需整合式研究方法。本研究构建了一套融合基于个体的模型（individual-based modelling）与统计推断的分析框架，用于评估伊比利亚半岛坎塔布连山脉棕熊种群动态的多种备选假说。纳入环境因子对死亡率影响的模型，能够复现近三十年来年度带幼崽母熊（females with cubs of the year, Fcoy）数量的变化趋势，包括1990年代中期该种群濒临灭绝时的数量下降过程，以及此后的种群恢复增长态势。相较于密度依赖调控机制（性选择杀婴行为与母熊繁殖抑制），该外源效应占据主导地位：其中气候驱动的资源可获取性变化为核心影响因子，人类活动压力变化仅发挥次要作用。种群结构的预测变化显示，种群总数量与Fcoy数量之间存在非线性关系，这凸显了基于间接种群数量指标开展简单种群预测的潜在风险。本研究证实了整合式机制研究方法的优势，并提供了一套可广泛推广的分析框架，助力学界深化对野生动物种群动态的认知。