title: Geographic variation and genetic structure in the Bahama Oriole (Icterus northropi), a critically endangered synanthropic species.
abstract: Bird species may exhibit unexpected population structuring over small distances, with gene flow restricted by geographic features such as water or mountains. The Bahama Oriole (Icterus northropi) is a critically endangered, synanthropic island endemic with a declining population of fewer than 300 individuals. It now remains only on Andros Island (The Bahamas), which is riddled with waterways that past studies assumed did not hinder gene flow. We examined 1,858 base pairs of mitochondrial DNA sequenced from four gene regions in 14 birds (roughly 5% of the remaining population) found on the largest land masses of Andros Island (North Andros and Mangrove Cay/South Andros). We sought to discern genetic structuring between the remaining subpopulations and its relationship to current conservation concerns. Four unique haplotypes were identified, with only one shared between the two subpopulations. Nucleotide and haplotype diversity were higher for the North Andros subpopulation than for the Mangrove Cay/South Andros subpopulation. Analysis of molecular variance (AMOVA) yielded a Wright's fixation index (F st) of 0.60 (P Fst = 0.016), with 40.2% of the molecular variation explained by within-population differences and 59.8% by among-population differences. Based on the mitochondrial regions examined in this study, we suggest the extant subpopulations of Bahama Oriole exhibit significant population structuring over short distances, consistent with some other non-migratory tropical songbird species.
authors.affiliation: Department of Natural Resources and Environmental Management, University of Hawai'i at Mānoa , Honolulu, HI , United States ; Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawaii at Manoa , Honolulu, HI , United States.
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Price
authors.affiliation: Department of Earth and Biological Sciences, Loma Linda University , Loma Linda, CA , United States.
authors.forename: Carl
authors.initials: C
authors.lastname: Person
authors.affiliation: Department of Earth and Biological Sciences, Loma Linda University , Loma Linda, CA , United States.
authors.forename: William K
authors.initials: WK
authors.lastname: Hayes
keywords: Conservation genetics; Non-migratory subtropical species; Ornithology; Population genetics; Single-island endemic species