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 reso...探明驱动濒危物种种群丰度波动的关键因素，是生态学领域的棘手难题，同时亦是实现高效物种管理与保护成效的核心前提。大型哺乳动物的生态学特征进一步提升了该研究的复杂度，故而亟需整合式研究方案。我们构建了一套融合基于个体的建模（individual-based modelling）与统计推断的研究框架，用于评估伊比利亚半岛坎塔布连山脉棕熊种群动态的多项备选假说。纳入环境因素对死亡率影响的模型，可复现过去三十年间年度带幼崽雌性棕熊（Females with Cubs of the Year, Fcoy）的数量变化趋势，其中既涵盖了20世纪90年代中期该种群濒临灭绝的数量下滑过程，也包含了此后棕熊种群的恢复增长态势。该外部环境效应的影响强度超越了密度依赖机制（性选择杀婴行为与雌性生殖抑制），其中气候驱动的资源变化发挥了核心作用