Data from: Hidden founder effects: small-scale spatial genetic structure in recently established populations of the grassland specialist plant Anthyllis vulneraria

The long-term establishment success of founder plant populations has been commonly assessed based on measures of population genetic diversity and among population genetic differentiation, with founder populations expected to carry sufficient genetic diversity when population establishment is the results of many colonists from multiple source populations (the ‘migrant pool’ colonization model). Theory, however, predicts that, after initial colonization, rapid population expansion may result in a fast increase in the extent of spatial genetic structure (SGS), independent of extant genetic diversity. This SGS can reduce long-term population viability by increasing inbreeding. Using 12 microsatellite markers, we inferred colonization patterns in four recent populations of the grassland specialist Anthyllis vulneraria and compared the extent of SGS between recently established and old populations. Assignment analyses of the individuals of recent population based on the genetic composition of nine adjacent putative source populations suggested the occurrence of the ‘migrant pool’ colonization model, further confirmed by high genetic diversity within and low genetic differentiation among recent populations. Population establishment, however, resulted in the buildup of strong SGS, most likely as a result of spatially restricted recruitment of the progeny of initial colonists. Although reduced, significant SGS was nonetheless observed to persist in old populations. Presence of SGS was in all populations associated with elevated inbreeding coefficients, potentially affecting the long-term viability of these populations. In conclusion, this study illustrates the importance of studying SGS next to population genetic diversity and differentiation to adequately infer colonization patterns and long-term establishment success of plant species.

奠基植物种群的长期建立成功率，通常通过种群遗传多样性与种群间遗传分化的相关指标进行评估。当种群建立源自多个源种群的大量定植个体时，奠基种群应携带充足的遗传多样性，即所谓的“迁移池（migrant pool）”定殖模型。然而理论预测，在初始定殖完成后，种群的快速扩张可独立于现存遗传多样性，快速提升空间遗传结构（spatial genetic structure, SGS）的发育水平。此类空间遗传结构会通过提升近交水平，降低种群的长期生存能力。本研究采用12个微卫星标记（microsatellite markers），对专性草原物种驴食豆（Anthyllis vulneraria）的4个新近建立种群的定殖模式进行了推断，并比较了新近建立种群与古老种群的空间遗传结构水平。基于9个相邻潜在源种群的遗传组成，对新近建立种群的个体开展归属分析，结果支持“迁移池”定殖模型的存在，这一结论进一步得到了新近种群内部较高遗传多样性、以及种群间较低遗传分化的验证。尽管如此，种群建立仍催生了强烈的空间遗传结构，这极有可能是初始定植者后代的招募过程在空间上受限所致。尽管有所减弱，但古老种群中仍存在显著的空间遗传结构。所有种群中，空间遗传结构的存在均与升高的近交系数相关，这可能会对这些种群的长期生存能力造成负面影响。综上，本研究阐明了：在充分推断植物物种的定殖模式与长期建立成功率时，除考量种群遗传多样性与分化水平外，对空间遗传结构开展研究同样具有重要意义。