Predation strongly limits demography of a keystone migratory herbivore in a recovering transfrontier ecosystem

Large herbivore migrations are imperiled globally; however, the factors limiting a population across its migratory range are typically poorly understood. Zambia’s Greater Liuwa Ecosystem (GLE) contains one of the largest remaining blue wildebeest (Connochaetes taurinus taurinus) migrations, yet the population structure, vital rates, and limiting factors are virtually unknown. We conducted a long-term demographic study of GLE wildebeest from 2012–2019 of 107 collared adult females and their calves, 7,352 herd observations, 12 aerial population surveys, and concurrent carnivore studies. We applied methods of vital rate estimation and survival analysis within a Bayesian estimation framework. From herd composition observations, we estimated rates of fecundity, first-year survival, and recruitment as 68%, 56%, and 38% respectively, with pronounced inter-annual variation. Similar rates were estimated from calf detections with collared cows. Adult survival rates declined steadily from 91% at a...全球范围内，大型草食动物的迁徙正面临生存威胁；然而，学界对其迁徙分布区内限制种群存续的关键因素往往缺乏深入认知。赞比亚大刘瓦生态系统（Greater Liuwa Ecosystem, GLE）拥有现存规模最大的蓝色牛羚（Connochaetes taurinus taurinus）迁徙种群之一，但该区域内牛羚的种群结构、生命率以及种群限制因素几乎尚未被系统研究。本研究于2012至2019年间针对大刘瓦生态系统的牛羚开展了长期种群生态学研究：共追踪107头佩戴卫星项圈的成年雌性牛羚及其幼崽，完成7352次种群群观测、12次航空种群调查，并同步开展了食肉动物相关研究。研究团队在贝叶斯估计框架下，运用生命率估算与生存分析方法开展数据分析。通过种群群组成观测，我们估算出牛羚的繁殖率、第一年存活率与种群补充率分别为68%、56%与38%，且各年份间存在显著的年际波动。通过佩戴项圈母羚的幼崽观测数据，我们得到了相近的估算结果。成年个体存活率从91%起持续呈下降趋势，在……