Climatic oscillations over the Quaternary have had a lasting impact on species’ distribution, evolutionary history, and genetic composition. Many species show dramatic population size changes coinciding with the last glacial period. However, the extent and direction of change vary across biogeographic regions, species-habitat associations, and species traits. Here we use genomic data to assess population size changes over the late Quaternary using the Pairwise Sequential Markovian Coalescent (PSMC) approach in two Eurasian Owlet species—the Spotted Owlet, Athene brama, and the Jungle Owlet, Glaucidium radiatum. While Spotted Owlets are typically associated with open habitats, Jungle Owlets are found in deciduous forests and scrublands. We find that the effective population size for the Spotted Owlet increased after the Interglacial period till the Last Glacial Maxima and subsequently declined toward the Mid-Holocene. On the other hand, effective population size estimates for the Jungle Owlet increased gradually throughout this period. These observations are in line with climatic niche model-based predictions for range size change for both species from a previous study and suggest that habitat associations at the local scale are important in determining responses to past climatic and vegetational changes. The Spotted Owlet result also aligns well with the expectation of open habitat expansion during the arid Glacial Maxima, whereas for the Jungle Owlet the contrasting expectation does not hold. Therefore, assessing the impacts of glacial history on population trajectories of multiple species with different habitat associations is necessary to understand the impacts of past climate on South Asian taxa.

中文翻译：

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晚第四纪来自南亚的两种欧亚鸮物种——Athene brama 和Glaucidium radiatum 种群规模变化的对比趋势

第四纪的气候波动对物种的分布、进化历史和遗传组成产生了持久的影响。许多物种在最后一次冰期期间显示出巨大的种群规模变化。然而，变化的程度和方向因生物地理区域、物种-栖息地关联和物种特征而异。在这里，我们使用基因组数据，在两种欧亚猫头鹰物种中使用成对序列马尔可夫聚结 (PSMC) 方法评估晚第四纪的种群规模变化 - 斑点猫头鹰，Athene brama 和丛林猫头鹰，Glaucidium radiatum。虽然斑点猫头鹰通常与开阔的栖息地有关，但丛林猫头鹰在落叶林和灌木丛中被发现。我们发现斑点鸮的有效种群规模在间冰期至末次冰期最大值后增加，随后向中全新世下降。另一方面，丛林猫头鹰的有效种群规模估计在此期间逐渐增加。这些观察结果与先前研究中基于气候生态位模型对两个物种范围大小变化的预测一致，并表明局部尺度的栖息地关联对于确定对过去气候和植被变化的响应很重要。Spotted Owlet 结果也与干旱冰川最大值期间开放栖息地扩张的预期一致，而对于丛林猫头鹰，相反的预期并不成立。所以，