Data from: Assessing current genetic status of the Hainan gibbon using historical and demographic baselines: implications for conservation management of species of extreme rarity

Evidence-based conservation planning is crucial for informing management decisions for species of extreme rarity, but collection of robust data on genetic status or other parameters can be extremely challenging for such species. The Hainan gibbon, possibly the world’s rarest mammal, consists of a single population of c.25 individuals restricted to one protected area on Hainan Island, China, and has persisted for over 30 years at exceptionally low population size. Analysis of genotypes at 11 microsatellite loci from faecal samples for 36% of the current global population and tissue samples from 62% of existing historical museum specimens demonstrates limited current genetic diversity (Na=2.27, Ar=2.24, He=0.43); diversity has declined since the 19th century and even further within the last 30 years, representing declines of c.30% from historical levels (Na=3.36, Ar=3.29, He=0.63). Significant differentiation is seen between current and historical samples (FST=0.156, P=0.0315), and the current population exhibits extremely small Ne (current Ne=2.16). There is evidence for both a recent population bottleneck and an earlier bottleneck, with population size already reasonably low by the late 19th century (historical Ne=1162.96). Individuals in the current population are related at the level of half- to full-siblings between social groups, and full-siblings or parent-offspring within a social group, suggesting that inbreeding is likely to increase in the future. The species’ current reduced genetic diversity must be considered during conservation planning, particularly for expectations of likely population recovery, indicating that intensive, carefully planned management is essential.基于证据的保护规划对于为极稀有物种制定管理决策至关重要，但针对这类物种收集遗传现状或其他参数的可靠数据却极具挑战性。海南长臂猿或许是全球最稀有的哺乳动物，其仅存约25只个体的单一种群，被限制在中国海南岛的一处保护区内，且已以极低的种群规模存续了30余年。通过对全球现存种群36%个体的粪便样本、以及62%现存历史博物馆标本的组织样本进行11个微卫星位点（microsatellite loci）的基因型分析，结果显示当前种群遗传多样性有限（Na=2.27, Ar=2.24, He=0.43）；遗传多样性自19世纪以来便呈下降趋势，近30年降幅更为显著，较历史水平下降了约30%（Na=3.36, Ar=3.29, He=0.63）。当前种群样本与历史标本样本间存在显著遗传分化（FST=0.156, P=0.0315），且当前种群的有效种群大小（Ne）极小，仅为2.16。研究证据显示该种群既经历过近期种群瓶颈，也存在更早的种群瓶颈事件，且至19世纪晚期时种群规模已处于较低水平（历史有效种群大小Ne=1162.96）。当前种群的个体间存在亲缘关系：不同社群间的个体为半同胞至全同胞关系，同一社群内的个体则为全同胞或亲子关系，这表明未来种群的近交程度大概率会进一步升高。在开展该物种的保护规划时，必须考虑到其当前已降低的遗传多样性，尤其是在预测种群恢复潜力时，这意味着精细化且经过周密规划的强化管理至关重要。