1. Translocation experiments can be used to study the factors limiting species' distributions and to infer potential drivers of successful colonisation during range shifts.
2. To study the expansion dynamics of the butterfly Pyrgus armoricanus in southern Sweden and to find out whether its distribution was limited by climate, translocation experiments were carried out within and 50–60 km beyond its natural range margin. Populations were monitored for 8 years following the translocation.
3. Although most translocation attempts failed, P. armoricanus was able to survive in two sites north of its current range limit. One of them eventually led to expansion and establishment of a viable metapopulation. Translocation success appeared to be independent of latitude, suggesting that climate is not the main factor determining the current northern distribution limits of this butterfly.
4. Population growth and secondary spread in the expanding population were positively related to patch area and connectivity, while local habitat quality seemed to be less important.
5. The successful translocation and the importance of a well‐connected patch network suggest that the current distribution of P. armoricanus is limited by its low dispersal ability combined with the fragmentation of its habitat, making it unlikely to track its changing climatic niche. Assisted migration could be an effective tool for such species, but long‐term evidence for its effectiveness is not yet available.

中文翻译：

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蝴蝶Pyrgus armilicanus易位后超出其北部范围边缘的种群动态

1. 易位实验可用于研究限制物种分布的因素，并推断范围转移期间成功定居的潜在驱动因素。
2. 为了研究瑞典南部蝴蝶Pyrgus armicalanus的膨胀动力学，并确定其分布是否受到气候的限制，在其自然范围边界外50-60 km内进行了易位实验。迁移后监测种群8年。
3. 尽管大多数易位尝试都失败了，但P. armilicanus仍能够在当前范围以北的两个地点生存。其中之一最终导致扩展并建立了可行的种群。易位成功似乎与纬度无关，这表明气候不是决定该蝴蝶当前北方分布范围的主要因素。
4. 人口增长和人口扩展中的次生扩散与斑块面积和连通性成正相关，而当地栖息地质量似乎不太重要。
5. 成功的易位和良好连接的补丁网络的重要性表明，P。armilicanus的当前分布受到其低散布能力以及栖息地破碎的限制，使其不太可能追踪其变化的气候生态位。辅助迁徙可能是这类物种的有效工具，但尚未获得其有效性的长期证据。