Data from: Recolonization after habitat restoration leads to decreased genetic variation in populations of a terrestrial orchid

Colonization is crucial to habitat restoration projects that rely on the spontaneous regeneration of the original vegetation. However, as a previously declining plant species spreads again, the likelihood of founder effects increases through recurrent population founding and associated serial bottlenecks. We related AFLP genetic variation and fitness of all extant populations of the outcrossing terrestrial orchid Dactylorhiza incarnata in an isolated coastal dune complex to colonization history. Around 1970, D. incarnata suffered a severe bottleneck yet eventually persisted and gradually spread throughout the spatially segregated dune slacks, aided by the restoration of an open vegetation. Genetic assignment demonstrated dispersal to vacant sites from few nearby extant populations and very limited inflow from outside the spatially isolated reserve. Results further indicated that recurrent founding from few local sources resulted in the loss of genetic diversity and promoted genetic divergence (FST=0.35) among populations, but did not influence population fitness. The few local sources initially available and the little gene inflow from outside the study reserve, as a consequence of respectively habitat degradation and spatial isolation, possibly magnified the genetic effects of recurrent population founding.对于依赖原生植被自然更新的生境恢复（habitat restoration）项目而言，拓殖（colonization）至关重要。然而，当曾一度衰退的植物物种重新扩散时，反复的种群建立及其伴随的连续瓶颈效应会增加奠基者效应（founder effect）的发生概率。本研究将异交陆生兰掌裂兰（Dactylorhiza incarnata）在孤立沿海沙丘复合体中的所有现存种群的扩增片段长度多态性（Amplified Fragment Length Polymorphism）遗传变异与适合度，与拓殖历史进行了关联分析。约1970年，掌裂兰经历了一次严重的瓶颈效应，但最终得以存续，并借助开阔植被恢复的助力，逐渐在空间分隔的沙丘湿洼地中扩散开来。遗传分配分析显示，空置生境的个体主要从附近少数现存种群扩散而来，该空间孤立保护区外的基因流入极为有限。研究结果进一步表明，从少数本地源种群反复建立种群的过程，造成了种群间遗传多样性的丧失并推动了遗传分化（固定指数Fst=0.35, Fixation Index Fst），但并未对种群适合度产生影响。分别受限于生境退化与空间隔离，研究区内初始可利用的本地源种群稀少、保护区外基因流入微弱，这可能放大了反复种群建立带来的遗传效应。