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修复项目而言，种群拓殖（colonization）至关重要。然而，当一种曾一度衰退的植物物种再度扩散时，反复的种群建立及伴随的连续性瓶颈效应，会提升奠基者效应（founder effect）出现的概率。本研究将一处隔离性海岸沙丘群中异交陆生兰淡红手兰（Dactylorhiza incarnata）所有现存种群的扩增片段长度多态性（AFLP，Amplified Fragment Length Polymorphism）遗传变异与适合度，与其拓殖历史相关联。约1970年，淡红手兰经历了一次严重的种群瓶颈，但最终得以存续，并借助开放型植被的修复工作，逐渐扩散至整片空间隔离的沙丘湿洼地。遗传归属分析结果显示，该物种向空白生境的扩散仅来自少数邻近的现存种群，且来自该空间隔离保护区外的基因流入极为有限。研究结果进一步表明，从少数本地源种群进行的反复拓殖，导致了种群内遗传多样性的丧失，并推动了种群间的遗传分化（FST=0.35），但并未对种群适合度产生影响。由于生境退化与空间隔离分别导致了初始可用本地源种群数量稀少、研究保护区外基因流入有限，这二者可能放大了反复种群拓殖带来的遗传效应。