“…All markers were highly polymorphic and allelic richness indicated similarly high level of genetic variation. Such maintenance of high genetic variation, despite great fluctuations in population density and thus possible threat of repetitive bottlenecks, has already been observed in yellow‐necked mouse (Gortat et al., ; Kozakiewicz et al., ; Rico et al., ) and in several vole species (e.g., Aars et al., ; Berthier et al., , ; Ehrich & Jorde, ; Ehrich et al., ; Gauffre, Estoup, Bretagnolle, & Cosson, ; Gauffre et al., ; Plante, Boag, & Bradley, ; Redeker et al., ; Rikalainen et al., ; Vuorinen & Eskelinen, ). The authors explained a minor impact of often dramatic decline in population size (up to 90% of population; Rikalainen et al., ) by constant and relatively large effective population size, intense migration negatively correlated with density, and the consequential accumulation of new alleles during the population peaks.…”