Genetic structure, diversity and evolutionary history of the Ivory Gull (Pagophila eburnea) and Ross's Gull (Rhodostethia rosea)

Royston, Stephanie Lynne (2008) Genetic structure, diversity and evolutionary history of the Ivory Gull (Pagophila eburnea) and Ross's Gull (Rhodostethia rosea). Masters thesis, Memorial University of Newfoundland.

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Abstract

The Ivory Gull (Pagophila eburnea) is classified as "Endangered" under the Species at Risk Act in Canada due to an 80% decline in population survey counts at known breeding sites between the early 1980s and 2003-2005. This study aimed to fill critical information gaps with regard to the Ivory Gull's global population structure, with a genomic approach of several mitochondrial gene sequences. Ivory Gulls have a low level of genetic diversity, similar to other endangered and arctic species. Most of the genetic variance is within populations, such that the Canadian, Greenland and Norwegian breeding populations are genetically indistinguishable and the source of the Labrador Sea wintering birds is unidentifiable. The Alaskan non-breeding population was weakly differentiated from the breeding colonies analyzed and the Labrador Sea wintering population. -- Ross's Gull (Rhodostethia rosea) is classified as Threatened in Canada due to the extremely small numbers of breeding birds. A small number of museum specimens were used to analyze the control region sequence. The genetic diversity of the Canadian birds was much lower than the Alaskan individuals and the two populations were weakly differentiated although the source of this was unclear.

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