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 dive...定居过程对于依托原生植被自然更新的生境修复项目而言至关重要。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瓶颈效应会提升奠基者效应发生的概率。本研究针对某孤立沿海沙丘群内异交陆生兰淡红手兰（Dactylorhiza incarnata）的全部现存种群，将其AFLP（扩增片段长度多态性）遗传变异与适合度指标，与其定居历史开展关联分析。约1970年，淡红手兰曾经历严重的瓶颈效应，但最终得以存续，并借助开放型植被修复的助力，逐渐扩散至整片空间隔离的沙丘洼地。遗传指派分析结果显示，该物种向空置生境的扩散仅来自少数邻近现存种群，且来自该空间孤立保护区之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，造成了遗传多样性的丧失，并推动了遗传分化……