Witnessing extinction: Population genetics of the last European Rollers ( Coracias garrulus ) in Austria and a first phylogeographic analysis of the species across its distribution range

Genetic diversity of a recovering European roller (Coracias garrulus) population from Serbia

The European Roller (Coracias garrulus), a long-distance migratory bird, faced a considerable decline in breeding pairs throughout Europe at the end of the 20th century. Due to conservation efforts and the installation of nesting boxes, the population of the European Roller in Serbia has made a remarkable recovery. Here, we used the variability of nucleotide sequences of the mitochondrial DNA (mtDNA) control region and 10 microsatellite loci to assess the genetic diversity and structuring, phylogeographic patterns and demographic history of this species using 224 individuals from Serbia. Our results showed moderate level of genetic diversity (HO = 0.392) and a slightly elevated level of inbreeding and homozygosity (FIS = 0.393). Genetic structuring based on microsatellite data indicated three genetic clusters, but without a clear spatial pattern. High haplotype diversity (Hd = 0.987) of the mtDNA control region sequences was detected, and neutrality tests indicated a recent demographic expansion. The phylogeographic analysis, which also included previously published sequences of the mtDNA control region, supported the subdivision into two distinct European and Asian haplogroups (ΦST = 0.712). However, the results of our study showed that a larger number of haplotypes sampled in Serbia are clustered in the Asian haplogroup as compared to previous studies, indicating a historically continuous distribution of this species and possibly a wider distribution of the subspecies Coracias garrulus semenovwi. Our results suggest that the European Roller population in Serbia is genetically stable, with no evidence of recent bottlenecks, and emphasize the importance of artificial nest boxes for promoting and maintaining population dynamics of European Rollers.