Genetic fate of the endangered Scarce fritillary Euphydryas maturna with a focus on East Central Europe

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Abstract DNA in museum collections harbours rich information on the past population genetics of endangered species, including butterflies. The remnant (meta)populations of Euphydryas maturna (Nymphalidae), a specialist of open-canopy woodlands, are imperilled by habitat loss and fluctuations in abundance; earlier allozyme studies documented low effective population sizes. Triggered by the fate of the last Czech population (extinct in the wild, highly inbred ex situ), we analysed 24 past, 17 recent, and 3 captive-reared population samples from Central Europe spanning over a century (past amplification rate: 72%). We also analysed 92 individuals for the mitochondrial COI barcode. The populations displayed higher expected (mean H e : 0.60) than observed ( H o : 0.36) heterozygosity, extreme inbreeding ( F IS : 0.39), and high differentiation ( F ST : 0.19). Time-defined samples from identical locations revealed cases of genetic deteriorations, but also extinctions not preceded by genetic declines, and genetic augmentation, possibly by unreported past transfers. The COI barcodes revealed 12 haplotypes, several of which were widespread across Europe and adjacent regions, with local derivatives in particular areas. The species was once persisting via metapopulation dynamics over contiguous open-canopy woodlands. Traditional forest uses contributed to its survival in progressively fragmented landscapes. We recommend crossing the inbred ex-situ individuals with butterflies from several extant populations for reintroductions. Restoring open-canopy woodlands is imperative for long-term survival of the species.