Département des Sciences Biologiques, Université du Québec à Montréal, CP-8888 Succursale Centre-Ville, Montréal, QC, Canada, H3C 3P8.
Mol Ecol. 2012 Nov;21(21):5363-73. doi: 10.1111/mec.12022. Epub 2012 Sep 27.
The study of the spatial distribution of relatives in a population under contrasted environmental conditions provides critical insights into the flexibility of dispersal behaviour and the role of environmental conditions in shaping population relatedness and social structure. Yet few studies have evaluated the effects of fluctuating environmental conditions on relatedness structure of solitary species in the wild. The aim of this study was to determine the impact of interannual variations in environmental conditions on the spatial distribution of relatives [spatial genetic structure (SGS)] and dispersal patterns of a wild population of eastern chipmunks (Tamias striatus), a solitary rodent of North America. Eastern chipmunks depend on the seed of masting trees for reproduction and survival. Here, we combined the analysis of the SGS of adults with direct estimates of juvenile dispersal distance during six contrasted years with different dispersal seasons, population sizes and seed production. We found that environmental conditions influences the dispersal distances of juveniles and that male juveniles dispersed farther than females. The extent of the SGS of adult females varied between years and matched the variation in environmental conditions. In contrast, the SGS of males did not vary between years. We also found a difference in SGS between males and females that was consistent with male-biased dispersal. This study suggests that both the dispersal behaviour and the relatedness structure in a population of a solitary species can be relatively labile and change according to environmental conditions.
在对比环境条件下研究种群中亲属的空间分布，为扩散行为的灵活性以及环境条件在塑造种群亲缘关系和社会结构方面的作用提供了重要的见解。然而，很少有研究评估波动的环境条件对野生独居物种亲缘关系结构的影响。本研究旨在确定环境条件的年际变化对东部花栗鼠（Tamias striatus）野生种群亲属的空间分布（空间遗传结构（SGS））和扩散模式的影响，东部花栗鼠是北美的一种独居啮齿动物，依赖于结实树木的种子进行繁殖和生存。在这里，我们将成年个体的 SGS 分析与六年不同扩散季节、种群大小和种子产量的直接估计的幼体扩散距离相结合。我们发现，环境条件影响幼体的扩散距离，雄性幼体的扩散距离比雌性远。成年雌性的 SGS 程度在不同年份之间有所不同，与环境条件的变化相匹配。相比之下，雄性的 SGS 程度在不同年份之间没有变化。我们还发现，雄性和雌性之间的 SGS 存在差异，这与雄性偏向的扩散一致。本研究表明，独居物种种群的扩散行为和亲缘关系结构都可能相对不稳定，并根据环境条件发生变化。
