Premise A good understanding of genetic variation and gene dispersal in tree populations is crucial for their sustainable management, particularly in a context of rapid environmental changes. West African Sudanian savannahs are being fragmented and degraded, partly due to expansion of crop cultivation and monocultures that reduce tree density and may impact pollinators. The population dynamics of important indigenous trees could also be affected. We investigated the influence of habitat fragmentation on patterns of genetic diversity and gene dispersal of a key Sudanian agroforestry tree species, Parkia biglobosa. Methods Using 10 highly polymorphic nuclear microsatellites, we genotyped 2475 samples from reproductive trees, seedlings, and embryos in four tree populations presenting different levels of habitat fragmentation. Results Parkia biglobosa presented similar high genetic diversity across the four populations studied. Genetic diversity and inbreeding were similar between adults and embryo cohorts. In all four populations, the selfing rate was less than 1%. The effective number of pollen donors per tree was high (N EP~ 18–22), as was the pollen immigration rate (from 34 to 74%). Pollen dispersal was characterized by a fat‐tailed distribution with mean estimates exceeding 200 m. In three populations, stem diameter had a pronounced effect on male reproductive success. Here, the highest male reproductive success was observed in trees with a diameter at breast height between 60 and 75 cm. Conclusions At the scale analyzed, fragmentation does not seem to pose limitations to gene flow in any of the sites investigated, regardless of the landscape configuration associated with the different tree stands. The study provides useful insights on the reproductive biology of an important tree species in the West African savannahs.

中文翻译：

---

不同生境破碎化程度的大叶凤梨种群的精细空间遗传结构、交配和基因扩散模式

前提 充分了解树木种群中的遗传变异和基因扩散对于它们的可持续管理至关重要，尤其是在环境快速变化的背景下。西非苏丹的大草原正在破碎和退化，部分原因是作物种植和单一栽培的扩大降低了树木密度并可能影响传粉媒介。重要的本土树木的种群动态也可能受到影响。我们调查了栖息地破碎化对苏丹主要农林业树种 Parkia biglobosa 的遗传多样性和基因扩散模式的影响。方法 使用 10 颗高度多态性核微卫星，我们对 2475 个样本进行了基因分型，这些样本来自 4 个呈现不同生境破碎程度的树种群的生殖树、幼苗和胚胎。结果 Parkia biglobosa 在所研究的四个种群中表现出相似的高遗传多样性。成虫和胚胎队列之间的遗传多样性和近亲繁殖相似。在所有四个种群中，自交率都低于 1%。每棵树的有效花粉捐赠者数量很高（N EP~18-22），花粉迁移率也很高（从 34% 到 74%）。花粉扩散的特征是肥尾分布，平均估计值超过 200 m。在三个种群中，茎直径对雄性繁殖成功有显着影响。在这里，在胸高直径在 60 到 75 厘米之间的树木中观察到最高的雄性繁殖成功率。结论 在分析的规模上，片段化似乎对任何研究位点的基因流动都没有限制，无论与不同树丛相关的景观配置如何。该研究为西非大草原中一种重要树种的生殖生物学提供了有用的见解。