Hull Joshua M, Hull Angus C, Sacks Benjamin N, Smith Jeff P, Ernest Holly B
Wildlife and Ecology Unit, Veterinary Genetics Laboratory, 258 CCAH, University of California, One Shields Avenue, Davis, CA 95616, USA.
Mol Ecol. 2008 Feb;17(3):810-24. doi: 10.1111/j.1365-294X.2007.03632.x. Epub 2008 Jan 14.
Landscape-scale population genetic structure in vagile vertebrates was commonly considered to be a contradiction in terms whereas recent studies have demonstrated behaviour and habitat associated structure in several such species. We investigate whether landscape features influence morphological and genetic differentiation in a widespread, mobile raptor. To accurately describe genetic differentiation associated with regional landscape factors, we first investigated subspecies relationships at a continental scale. We used 17 microsatellite loci and five morphological measurements to investigate differentiation between eastern and western subspecies of red-tailed hawks (Buteo jamaicensis) and to identify patterns between differentiation and habitat within western North America. Bayesian and frequency-based analyses of microsatellite data revealed clear distinctions between B. j. borealis (eastern) and B. j. calurus (western) samples. Furthermore, hawks sampled in Texas were stouter than those collected from the Rocky Mountains and farther west. Among western samples, birds from the Great Basin, Rocky Mountains, and Washington were significantly different in morphology than those from Oregon and California. We identified a pattern of isolation by distance among western breeding sites around the Sierra Nevada. Given the long-range dispersal capabilities of raptors, this pattern suggests that population-specific habitat preferences, corresponding with habitat breaks between eastern and western slopes of the Sierra Nevada, and/or regionally variable population densities limit migration between the Mediterranean habitat of central California and the xeric habitats of southern California and interior west. We suggest habitat preferences and regionally disparate population densities may play a role in shaping genetic structure in vagile avian taxa.
在易迁移的脊椎动物中，景观尺度的种群遗传结构通常被认为是自相矛盾的，然而最近的研究表明，在一些此类物种中存在与行为和栖息地相关的结构。我们调查景观特征是否会影响一种分布广泛、善于移动的猛禽的形态和遗传分化。为了准确描述与区域景观因素相关的遗传分化，我们首先在大陆尺度上研究了亚种关系。我们使用17个微卫星位点和5种形态测量方法，来研究红尾鹰（Buteo jamaicensis）东部和西部亚种之间的分化，并确定北美西部内部分化与栖息地之间的模式。对微卫星数据的贝叶斯分析和基于频率的分析揭示了北方红尾鹰（东部）和加州红尾鹰（西部）样本之间的明显差异。此外，在得克萨斯州采集的鹰比从落基山脉及更西部采集的鹰体型更粗壮。在西部样本中，来自大盆地、落基山脉和华盛顿的鸟类在形态上与来自俄勒冈州和加利福尼亚州的鸟类有显著差异。我们在内华达山脉周围的西部繁殖地之间发现了一种距离隔离模式。鉴于猛禽具有远距离扩散能力，这种模式表明，特定种群的栖息地偏好，与内华达山脉东西坡之间的栖息地断裂相对应，和/或区域可变的种群密度限制了加利福尼亚中部的地中海栖息地与加利福尼亚南部和内陆西部的干旱栖息地之间的迁移。我们认为，栖息地偏好和区域不同的种群密度可能在塑造易迁移鸟类类群的遗传结构中发挥作用。
