Data from: Sympatric population divergence within a highly pelagic seabird species complex (Hydrobates spp.)

Both physical and non-physical barriers can restrict gene flow among seabird populations. Understanding the relative importance of non-physical barriers, such as breeding phenology, is key to understanding seabird biodiversity. We investigated drivers of diversification in the Leach’s storm-petrel species complex (Hydrobates spp.) by examining population genetic structure across its range. Variation in the mitochondrial control region and six microsatellite loci was assayed in birds sampled from breeding colonies throughout the North Atlantic and North Pacific (H. leucorhoa leucorhoa), as well as from San Benito Islands (H. l. chapmani), and two seasonal populations in Guadalupe (summer breeding H. socorroensis and winter breeding H. cheimomnestes), Mexico. Weak but significant differentiation was found between populations of H. l. leucorhoa breeding in the Atlantic versus North Pacific, as well as between H. l. chapmani and H. l. leucorhoa, and between H. socorroensis and H. cheimomnestes within Guadalupe. In contrast, strong differentiation in both mitochondrial DNA and microsatellites was found between H. leucorhoa and both H. socorroensis and H. cheimomnestes. Phylogenetic reconstruction suggested the Guadalupe seasonal breeding populations are sister taxa, at least in their mitochondrial DNA. Non-physical barriers to gene flow appear to be more important than physical barriers in driving divergence within the Leach’s storm-petrel species complex. In particular, allochronic speciation may have occurred between the seasonal populations within Guadalupe. Further work should include higher resolution sequencing to confirm results, and an increased sampling effort, particularly within the California area, to fully resolve the relationship between H. l. leucorhoa and H. l. chapmani.物理屏障与非物理屏障均可限制海鸟种群间的基因流（gene flow）。明晰非物理屏障（如繁殖物候（breeding phenology））的相对重要性，是解析海鸟生物多样性的关键所在。本研究以利奇氏风暴海燕（Leach’s storm-petrel）物种复合群（叉尾海燕属Hydrobates spp.）为研究对象，通过解析其分布范围内的种群遗传结构，探讨其物种分化的驱动因子。研究团队对采集自北大西洋、北太平洋全域繁殖群落的H. l. leucorhoa（指名亚种）、墨西哥圣贝尼托群岛的H. l. chapmani（瓜达卢普亚种），以及墨西哥瓜达卢普岛的两个季节性繁殖种群（夏季繁殖的H. socorroensis与冬季繁殖的H. cheimomnestes）的样本，进行了线粒体控制区（mitochondrial control region）与6个微卫星位点（microsatellite loci）的变异检测。研究发现，北大西洋与北太平洋的H. l. leucorhoa种群间、H. l. chapmani与H. l. leucorhoa间，以及瓜达卢普岛的H. socorroensis与H. cheimomnestes间，均存在微弱但显著的遗传分化。与之形成对比的是，利奇氏风暴海燕（H. leucorhoa）与社氏叉尾海燕、切氏叉尾海燕之间，在线粒体DNA与微卫星位点上均呈现出强烈的遗传分化。系统发育重建（phylogenetic reconstruction）结果显示，瓜达卢普岛的季节性繁殖种群互为姊妹群，至少在线粒体DNA层面如此。在利奇氏风暴海燕物种复合群的种群分化过程中，非物理基因流屏障的作用似乎较物理屏障更为关键。具体而言，瓜达卢普岛的两个季节性繁殖种群间可能发生了异时成种（allochronic speciation）。未来研究可采用更高分辨率的测序技术以验证本研究结果，并扩大采样范围（尤其是加利福尼亚地区），以完全阐明H. l. leucorhoa与H. l. chapmani之间的系统发育关系。