Data from: Landscape structure and the genetic effects of a population collapse

<b>Abstract</b><br/>Both landscape structure and population size fluctuations influence population genetics. While independent effects of these factors on genetic patterns and processes are well studied, a key challenge is to understand their interaction, as populations are simultaneously exposed to habitat fragmentation and climatic changes that increase variability in population size. In a population network of an alpine butterfly, abundance declined 60–100% in 2003 because of low over-winter survival. Across the network, mean microsatellite genetic diversity did not change. However, patch connectivity and local severity of the collapse interacted to determine allelic richness change within populations, indicating that patch connectivity can mediate genetic response to a demographic collapse. The collapse strongly affected spatial genetic structure, leading to a breakdown of isolation-by-distance and loss of landscape genetic pattern. Our study reveals important interactions between landscape structure and temporal demographic variability on the genetic diversity and genetic differentiation of populations. Projected future changes to both landscape and climate may lead to loss of genetic variability from the studied populations, and selection acting on adaptive variation will likely occur within the context of an increasing influence of genetic drift.

**摘要**
景观结构与种群大小波动均会对种群遗传学产生影响。尽管二者对遗传模式与遗传过程的独立效应已得到充分研究，但理解其交互作用仍是核心挑战——因为种群同时面临生境破碎化与加剧种群大小波动的气候变化的双重影响。本研究以一种高山蝴蝶的种群网络为研究对象，受越冬存活率低下影响，2003年其种群丰度下降了60%至100%。整体而言，该网络内种群的平均微卫星（microsatellite）遗传多样性未发生显著变化。但斑块连通性与种群衰退的局地严重程度共同决定了种群内的等位基因丰富度变化，表明斑块连通性可调节种群对数量衰退的遗传响应。此次衰退还显著改变了空间遗传结构，导致距离隔离格局瓦解，同时丧失了原有的景观遗传特征。本研究揭示了景观结构与时间尺度上的种群数量波动对种群遗传多样性与遗传分化的重要交互作用。未来景观与气候的预期变化可能导致本研究涉及的种群丧失遗传变异，而随着遗传漂变的影响日益增强，针对适应性变异的选择作用也将在这一背景下发生。