Phylogeography and management of snow, Ross's, Canada, and cackling geese

With the development and greater accessibility of molecular techniques, genetic surveys can be conducted to determine the degree of genetic variation for currently defined populations, subspecies, and species of waterfowl. Molecular phylogenies based on maternally- (mitochondrial DNA) and bi-parentally- (neutral nuclear DNA) inherited markers can be examined in a spatial context, and be used to assess the relative influence of historical processes and current behavioral and ecological factors on the spatial genetic structure revealed for specific waterfowl taxa.;This study focused on two co-distributed species groups of migratory waterfowl in North America that have similar historical geographic ranges. Populations, subspecies, and species of these two groups, including snow ( Chen caerulescens) and Ross's geese (Chen rossii) and cackling (Branta hutchinsii) and Canada geese ( Branta canadensis) were genetically characterized using mitochondrial and microsatellite molecular markers. These molecular surveys were designed to evaluate the degree of genetic variation at multiple spatial levels, and identify areas of genetic discordance within and among species. Hypotheses were then tested regarding the relative importance of causal historical and contemporary factors that have defined the genetic spatial structure observed. Finally, a determination was made as to whether the present species, subspecies, and management unit designations for each group of geese reflected the underlying spatial structure as seen at the level of genes.;Data collected as part of the phylogenetic investigation were then utilized to address specific issues of population management in snow geese and within cackling and Canada geese. For snow geese, information regarding the degree of genetic variation among Western populations was used to determine relative levels of historical and contemporary gene flow among populations of conservation concern, and to evaluate population structuring among breeding and wintering groups of these populations. To improve harvest management in the state of Michigan, established methods of genetic stock identification and nationally standardized sample collections were used to estimate proportional contributions of cackling and Canada geese to annual harvests. (Abstract shortened by UMI.)...