Genetic structure and diversity of the endangered fir tree of Lebanon (Abies cilicica Carr.): implications for conservation

The threatened conifer Abies cilicica currently persists in Lebanon in geographically isolated forest patches. The impact of demographic and evolutionary processes on population genetic diversity and structure were assessed using 10 nuclear microsatellite loci. All remnant 15 local populations revealed a low genetic variation but a high recent effective population size. FST-based measures of population genetic differentiation revealed a low spatial genetic structure, but Bayesian analysis of population structure identified a significant Northeast-Southwest population structure. Populations showed significant but weak isolation-by-distance, indicating non-equilibrium conditions between dispersal and genetic drift. Bayesian assignment tests detected an asymmetric Northeast-Southwest migration involving some long-distance dispersal events. We suggest that the persistence and Northeast-Southwest geographic structure of Abies cilicica in Lebanon is the result of at least two demographic proc...

受威胁的针叶树种西里西亚冷杉（Abies cilicica）目前仅在黎巴嫩残存于地理隔离的林分斑块中。本研究利用10个核微卫星位点，评估了人口统计学过程与进化过程对种群遗传多样性及遗传结构的影响。全部15个残存本地种群均表现出较低的遗传变异水平，但近期有效种群规模较高。基于FST的种群遗传分化测度显示其空间遗传结构较弱，但种群结构的贝叶斯分析鉴定出显著的东北-西南方向种群遗传格局。种群间呈现显著但微弱的距离隔离效应，表明扩散与遗传漂变之间处于非平衡状态。贝叶斯归属检验检测到不对称的东北-西南方向迁移事件，涉及多起长距离扩散事件。我们推测，西里西亚冷杉在黎巴嫩的存续现状及其东北-西南方向的地理遗传结构，至少由两类人口统计学过程塑造而成……