Genetic diversity in over-exploited and threatened species has important, but often neglected, implications for conservation. In South Africa, the bark of the regionally endangered pepper-bark tree, Warburgia salutaris, is extensively harvested for subsistence medicine. We developed 11 polymorphic microsatellite markers to examine the genetic diversity and structure among 227 W. salutaris individuals sampled from across much of its range in South Africa’s Kruger National Park (KNP) and 31 trees growing in local nurseries. We also tested the cross-amplification success of these markers in two closely related species, Warburgia elongata (IUCN listed as Endangered) and W. stuhlmannii (IUCN listed as Vulnerable). Contrary to our expectations, we found evidence of clonality and for high genetic diversity in all wild KNP sub-populations of W. salutaris. We identified between 114 and 149 unique multi-locus genotypes in the 258 individuals included in our analyses. Bayesian assignment tests identified three distinct genetic clusters that are represented by the sampled KNP sub-population of W. salutaris, with minimal geographic structure and some admixture. Three genetic clusters were also identified among all sampled individuals, i.e., KNP and nursery trees. Nursery W. salutaris germplasm comprised unique genotypes with similar levels of observed heterozygosity to the wild population. High levels of clonality and reported self-incompatibility, along with short distance pollination, likely explain the lack of recent sexual recruitment (i.e., reduced fruit set and lack of seedlings) in the wild population. These findings will be useful to identify sub-populations where genets may be sampled to maximize genetic diversity within subpopulations for restoration throughout KNP.

过度开发和受威胁物种的遗传多样性对保护具有重要但常常被忽视的影响。在南非，当地濒临灭绝的胡椒树Warburgia salutaris的树皮被广泛采伐用于维持生计的药物。我们开发了 11 个多态性微卫星标记，以检查 227 个W. salutaris个体的遗传多样性和结构，这些个体 采样自南非克鲁格国家公园 (KNP) 的大部分分布范围，以及当地苗圃中生长的 31 棵树。我们还在两个密切相关的物种Warburgia elongata  （IUCN 列为濒危物种）和W. Stuhlmannii中测试了这些标记的交叉扩增成功率（世界自然保护联盟将其列为易危物种）。与我们的预期相反，我们在W. salutaris的所有野生 KNP 亚群中发现了克隆性和高遗传多样性的证据。我们在分析中包含的 258 名个体中鉴定出了 114 至 149 种独特的多位点基因型。贝叶斯分配测试确定了三个不同的遗传簇，它们以W. salutaris的 KNP 亚群样本为代表，具有最小的地理结构和一些混合。在所有采样个体中还鉴定出了三个遗传簇，即 KNP 和苗木。苗圃W. salutaris种质包含独特的基因型，观察到的杂合性水平与野生种群相似。高水平的克隆性和报道的自交不亲和性，以及短距离授粉，可能解释了野生种群中近期性招募的缺乏（即坐果减少和幼苗缺乏）。这些发现将有助于确定亚群，在这些亚群中可以对基因进行采样，以最大限度地提高亚群内的遗传多样性，从而在整个 KNP 中进行恢复。