Kalahari vulture declines, through the eyes of meerkats§

Vulture populations are experiencing rapid declines across the globe. While the declines have been most precipitous in Asia, recent reports suggest African populations are likewise imminently threatened. As the factors underlying these general population trends are multifaceted and will vary in their relative intensity spatially, it is imperative that monitoring data across different vulture populations is assimilated if targeted conservation action is to prove most effective. In this study, we highlight a medium-term decline in the African White-backed Vulture Gyps africanus population inhabiting the southern Kalahari, South Africa, using a long-term behavioural data set collected from a habituated population of meerkats Suricata suricatta. Meerkats emit an alarm call on sighting airborne vultures, which elicits a group-level response, such that the rates at which this behaviour is recorded in meerkats provides a high-resolution proxy for local vulture abundance. Although unconventional, this sampling method uncovered a steady decline over 17 years in White-backed Vulture numbers that mirrors the temporal decline recently documented in other southern African populations.全球秃鹫种群正经历快速衰退。其中亚洲地区的种群衰退幅度最为急剧，近期报告显示非洲秃鹫种群同样面临迫在眉睫的生存威胁。由于此类种群衰退的驱动因素复杂多元，且其相对影响强度存在空间异质性，若要制定最具针对性的高效保护行动，就必须整合不同区域秃鹫种群的监测数据。本研究依托南非南部喀拉哈里地区一群已适应人类活动的狐獴（Suricata suricatta）的长期行为数据集，揭示了当地栖息的白背秃鹫（Gyps africanus）种群存在中期衰退现象。狐獴在发现空中的秃鹫时会发出警戒叫声，进而触发群体层面的响应行为，因此记录到的该类警戒行为发生频率，可作为当地秃鹫种群丰度的高分辨率替代指标。尽管该采样方法并非传统常规手段，但它仍揭示出17年间白背秃鹫种群数量的持续下降趋势，这与近期南部非洲其他地区同类种群所记录到的时间序列衰退趋势相一致。