Genetic erosion at the range margin: a historical baseline for the endangered garden dormouse (Eliomys quercinus) in Central Europe
Description
The garden dormouse (Eliomys quercinus) has experienced marked population contractions and fragmentation across Central Europe, leaving peripheral populations highly vulnerable to extinction. This study establishes a crucial historical reference framework by assessing the population genetic diversity and structure of 85 individuals from peripheral (Czech Republic) and core (Luxembourg) regions, captured shortly before contemporary collapses. Using nine newly developed, species-specific microsatellite loci, we found that peripheral Czech populations exhibited significantly lower allelic richness (AR= 1.78–2.30) and expected heterozygosity (He = 0.35–0.41) than core Luxembourgian populations (AR= 2.45–2.94); (He = 0.51–0.55), reflecting intense isolation. Significant deviations from Hardy-Weinberg equilibrium and elevated fixation indices (FIS up to 0.297) occurred in most forest populations, whereas a synanthropic Luxembourgian population maintained genetic stability (FIS = 0.056). Pairwise FST values up to 0.192 and Bayesian clustering revealed profound genetic differentiation between regional clusters, driven primarily by historical genetic drift. Conversely, gene flow remained high within the Bohemian Forest over distances of approximately 15 kilometres. Landscape features like rivers partially restricted gene flow, whereas rocky microhabitats supported connectivity. Our results provide an irreplaceable historical baseline capturing the genetic architecture of the Western European lineage prior to major recent bottlenecks. These novel microsatellite loci represent a robust, accessible tool for future non-invasive genetic monitoring and the implementation of regional conservation strategies for this endangered rodent.
Files
Steps to reproduce
the Eliomys_dataset_msat file, treat -9 as missing data, and analyze the nine microsatellite loci using the procedures described in the manuscript.