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，定植（colonization）至关重要。然而，当一种此前处于衰退状态的植物物种再度扩散时，反复的种群建立及伴随的连续瓶颈效应会使其遭遇奠基者效应（founder effects）的概率上升。本研究针对一处孤立的沿海沙丘群中所有现存的异交陆生兰——肉质掌裂兰（Dactylorhiza incarnata）种群的扩增片段长度多态性（AFLP）遗传变异与适合度，与定植历史之间的关联展开分析。约1970年，肉质掌裂兰（Dactylorhiza incarnata）遭遇了严重的种群瓶颈，但最终得以存续，并借助开放型植被修复的助力，逐渐在空间隔离的沙丘湿洼地中扩散开来。遗传指派分析结果显示，该物种向空白生境的扩散主要来自附近少量现存种群，且来自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，从少量本地源种群反复建立新种群的过程，造成了种群遗传多样性的丧失，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、保护区外基因流入匮乏，这二者可能放大了反复种群建立所带来的遗传效应。