Data from: Hybridization following population collapse in a critically endangered antelope

Population declines may promote interspecific hybridization due to the shortage of conspecific mates (Hubb’s ‘desperation’ hypothesis), thus greatly increasing the risk of species extinction. Yet, confirming this process in the wild has proved elusive. Here we combine camera-trapping and molecular surveys over seven years to document demographic processes associated with introgressive hybridization between the critically endangered giant sable antelope (Hippotragus niger variani), and the naturally sympatric roan antelope (H. equinus). Hybrids with intermediate phenotypes, including backcrosses with roan, were confirmed in one of the two remnant giant sable populations. Hybridization followed population depletion of both species due to severe wartime poaching. In the absence of mature sable males, a mixed herd of sable females and hybrids formed and grew progressively over time. To prevent further hybridization and recover this small population, all sable females were confined to a large enclosure, to which sables from the other remnant population were translocated. Given the large scale declines in many animal populations, hybridization and introgression associated with the scarcity of conspecific mates may be an increasing cause of biodiversity conservation concern. In these circumstances, the early detection of hybrids should be a priority in the conservation management of small populations.

种群数量下降可能因同种配偶短缺而促进种间杂交（interspecific hybridization）——即哈勃“绝望”假说（Hubb’s ‘desperation’ hypothesis），这将大幅提升物种灭绝风险。然而，在野外证实这一过程始终颇具挑战。本研究耗时七年，结合相机陷阱监测（camera-trapping）与分子调查手段，记录了极危物种大黑马羚（Hippotragus niger variani）与自然同域分布的马羚（H. equinus）之间的渐渗杂交（introgression hybridization）相关种群动态过程。在两个残存大黑马羚种群中的一个内，已确认存在具有中间表型的杂交个体，包括与马羚的回交（backcross）个体。此次杂交事件发生于两个物种因战时严重偷猎导致种群锐减之后。在缺乏成熟雄性大黑马羚的情况下，由大黑马羚雌性与杂交个体组成的混合种群随时间推移不断壮大。为防止进一步杂交并恢复该小种群，所有大黑马羚雌性被安置于大型围栏中，并将另一个残存种群的大黑马羚迁至此围栏。鉴于众多动物种群正经历大规模数量下降，由同种配偶稀缺引发的杂交与渐渗现象，或正成为生物多样性保护领域日益值得关注的问题。在此类情形下，早期检测杂交个体应成为小种群保护管理的优先事项。