Conservation genetics of a resident population of Greylag Goose (Anser anser) at the southernmost limit of the species' distribution in Europe

Abstract

Background: Conservation of small and isolated populations can be challenging since they are prone to loss of genetic diversity due to random genetic drift and inbreeding. Therefore, information from the assessment of genetic diversity and structure are needed for conservation programs to determine the appropriate management strategy for the populations. We investigated the levels of genetic variability in a resident Greylag Goose (Anser anser) population, the southernmost breeding population of the species in Europe and the sole viable population of any goose species in Greece. Methods: A fragment of mtDNA Control Region and a panel of 11 microsatellite markers were used to search for any signs of genetic impoverishment and population substructure and to reveal the underlying processes through the identification of possible past demographic events. Results: The population was found to be monomorphic in the amplified fragment of the mitochondrial Control Region, with all individuals sharing a single private haplotype. Analyses showed a lack of any population substructure indicating a panmictic population. Although the population seems to have experienced a strong and recent genetic bottleneck and exhibits a small effective population size, we did not find evidence of either extremely low levels of genetic diversity or inbreeding depression. Conclusions: The recent demographic decline we detected and the combined influence of residency and anthropogenic factors have probably shaped the current genetic status. Our study population does not need emergency conservation actions but should be regarded as a discrete management unit. Future management strategies should focus on population and genetic monitoring and preventing further abundance declines that would increase the risk of genetic impoverishment.