Phylogeography of colonially nesting seabirds, with special reference to global matrilineal patterns in the sooty tern (Sterna fuscata)

Sooty tern (Sterna fuscata) rookeries are scattered throughout the tropical oceans. When not nesting, individuals wander great distances across open s eas, but, like many other seabirds, they tend to be site-faithful to nestin g locales in successive years. Here we examine the matrilineal history of s ooty terns on a global scale. Assayed colonies within an ocean are poorly d ifferentiated in mitochondrial DNA sequence, a result indicating tight hist orical ties. However, a shallow genealogical partition distinguishes Atlant ic from Indo-Pacific rookeries. Phylogeographic patterns in the sooty tern are compared to those in other colonially nesting seabirds, as well as in t he green turtle (Chelonia mydas), an analogue of tropical seabirds in some salient aspects of natural history. Phylogeographic structure within an oce an is normally weak in seabirds, unlike the pronounced matrilineal structur e in green turtles. However, the phylogeographic partition between Atlantic and Indo-Pacific rookeries in sooty terns mirrors, albeit in shallower evo lutionary time, the major matrilineal subdivision in green turtles. Thus, g lobal geology has apparently influenced historical gene movements in these two circumtropical species.