1. The persistence and adaptation of leading‐edge peripheral populations may be critical for allowing species to shift their range limits under climate change. However, peripheral populations are potentially vulnerable to genetic, demographic, and environmental stochasticity.
2. Here, we characterise genetic variation across space and among years in northern peripheral populations of the Behr's hairstreak butterfly in British Columbia, Canada. This butterfly is dependent on antelope‐brush ecosystems that are threatened in this part of the world and is federally listed as Endangered in Canada.
3. Using a large panel of amplified fragment length polymorphism (AFLP) genetic markers, we found low diversity in these populations. We also detected a high degree of year‐to‐year variation in allele frequencies, resulting in low effective population size estimates.
4. Our findings suggest that Canadian populations of the Behr's hairstreak experience high genetic drift and may be vulnerable to genetic stochasticity.
5. Unstable demography, low effective population size, and low genetic diversity in these populations could impede their adaptation to rapidly changing environmental conditions and contribute to a contraction of the species' range under climate change.

中文翻译：

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濒临灭绝的贝hr蝴蝶（Satyrium behrii）的北部外围种群中的高遗传漂移

1. 前沿边缘种群的持久性和适应性可能对于允许物种在气候变化下改变其范围限制至关重要。但是，外围人群可能容易受到遗传，人口和环境随机性的影响。
2. 在这里，我们描述了加拿大不列颠哥伦比亚省贝hr蝴蝶的北部外围种群跨空间和多年间遗传变异的特征。这只蝴蝶依赖于在这一地区受到威胁的羚羊刷生态系统，在加拿大被联邦列为“濒危物种”。
3. 使用大量的扩增片段长度多态性（AFLP）遗传标记，我们发现这些人群的多样性较低。我们还检测到等位基因频率逐年高度变化，从而导致有效人口规模估算值偏低。
4. 我们的发现表明，加拿大Behr的发际线人群经历了高度的遗传漂移，可能容易受到遗传随机性的影响。
5. 这些人口的人口统计不稳定，有效种群数量少，遗传多样性低，可能会阻碍其适应快速变化的环境条件，并导致气候变化下物种范围的缩小。