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Long-term isolation of a highly mobile seabird on the Galapagos

September 1, 2011

The Galapagos Islands are renowned for their high degree of endemism. Marine taxa inhabiting the archipelago might be expected to be an exception, because of their utilization of pelagic habitats—the dispersal barrier for terrestrial taxa—as foraging grounds. Magnificent frigatebirds (Fregata magnificens) have a highly vagile lifestyle and wide geographical distribution around the South and Central American coasts. Given the potentially high levels of gene flow among populations, the species provides a good test of the effectiveness of the Galapagos ecosystem in isolating populations of highly dispersive marine species. We studied patterns of genetic (mitochondrial DNA, microsatellites and nuclear introns) and morphological variation across the distribution of magnificent frigatebirds. Concordant with predictions from life-history traits, we found signatures of extensive gene flow over most of the range, even across the Isthmus of Panama, which is a major barrier to gene flow in other tropical seabirds. In contrast, individuals from the Galapagos were strongly differentiated from all conspecifics, and have probably been isolated for several hundred thousand years. Our finding is a powerful testimony to the evolutionary uniqueness of the taxa inhabiting the Galapagos archipelago and its associated marine ecosystems.

Publication Year 2011
Title Long-term isolation of a highly mobile seabird on the Galapagos
DOI 10.1098/rspb.2010.1342
Authors Frank Hailer, E.A. Schreiber, Joshua M. Miller, Iris I. Levin, Patricia G. Parker, R. Terry Chesser, Robert C. Fleischer
Publication Type Article
Publication Subtype Journal Article
Series Title Proceedings of the Royal Society B: Biological Sciences
Index ID 70004034
Record Source USGS Publications Warehouse
USGS Organization Patuxent Wildlife Research Center