Genetic Analysis of Spatial and Temporal Variation in Racial Composition of Harvested Canada Geese in Michigan.

摘要

Racial identification of Canada geese (Branta canadensis) has historically relied on marking individuals or measuring phenotypic characteristics that are naturally variable. Genetic markers and methods of statistical inference are currently available to estimate proportional contributions of races or breeding populations to admixed wintering or migratory flocks. We derive estimates of the composition of Michigan's fall harvest of Canada geese from Wildlife Management Areas in 2 regions (southwest Michigan, east-central Michigan) for the first 2 days of the regular hunting season in each of 4 years (1993-96). Harvest samples were also obtained from early and/or late seasons in 3 additional locales in the state. Breeding populations in Canada (B.c. interior; N=4) and Michigan (B.c. maxima; N=5) were characterized for 5 microsatellite loci that were identified as providing accurate and precise estimates of the proportional contribution of samples from each population based on significant sub-specific and inter-population differences in allele frequency. Maximum likelihood estimates of the proportional contributions of breeding populations to fall harvests revealed that the racial composition also varied greatly between managed and unmanaged areas in close geographic proximity. Higher proportions of resident giant Canada geese were harvested during early hunting seasons and on unmanaged areas relative to migratory interior Canada geese.