Low genetic differentiation among reed warbler Acrocephalus scirpaceus populations across Europe


  • Petr Procházka,

  • Bård G. Stokke,

  • Henrik Jensen,

  • Drahomíra Fainová,

  • Erica Bellinvia,

  • Frode Fossøy,

  • Johan R. Vikan,

  • Josef Bryja,

  • Manuel Soler

P. Procházka (prochazka@ivb.cz), D. Fainová, E. Bellinvia and J. Bryja, Inst. Vertebrate Biol., Acad. Sci. Czech Republic, v.v.i., Květná 8, CZ-603 65 Brno, Czech Republic. – B. G. Stokke, F. Fossøy and J. R. Vikan, Dept of Biol., Norwegian Univ. of Sci. Techn., Realfagbygget, NO-7491 Trondheim, Norway. – H. Jensen, Centre Conserv. Biol., Dept of Biol., Norwegian Univ. Sci. Techn., Realfagbygget, NO-7491 Trondheim, Norway. – D. F. also at Dept of Zool., Faculty of Sci., Univ. South Bohemia, Branišovská 31, CZ-370 05 České Budějovice, Czech Republic. – M. Soler, Depto de Biol. Anim., Facult. Ciencias, Univ. de Granada, ES-18071 Granada, Spain. – M. S. also at Centre for Adv. Stud., Norwegian Acad. Sci. Let., Drammensveien 78, NO-0271 Oslo, Norway and Grupo Coevol., Unidad Asociada al CSIC, Univ. Granada, Spain. – E. B. currently at Dept of Plant Physiol., Faculty of Sci., Charles Univ., Viničná 5, CZ-128 44 Praha 2, Czech Republic.


Migratory birds generally have higher dispersal propensity than resident species and are thus expected to show less genetic differentiation. On the other hand, specific migration patterns may promote genetic structure, such as in situations where migratory divides impede random mixing of individuals. Here we investigated population genetic structure and gene flow patterns in a polytypic passerine, the reed warbler Acrocephalus scirpaceus which shows a migratory divide in central Europe. Using ten polymorphic microsatellite loci and extensive sampling we found low but significant overall genetic differentiation (FST=0.013, G’ST=0.078, D=0.063). Hierarchical F-statistics and barrier analyses showed low but significant genetic differentiation of Iberian populations, and also slight genetic differences across the migratory divide and between subspecies (A. s. scirpaceus and A. s. fuscus). Three individual-based Bayesian methods, however, inferred a single genetic unit. Our study thus found low levels of genetic differentiation among reed warbler populations but this genetic differentiation was not pronounced enough to detect a clear population structure using the microsatellite data and no prior information on geographic location of the sampled individuals. This result indicates high levels of gene flow and suggests a possibly recent divergence of European populations after a rapid range expansion. Further studies are necessary to assess divergence times and to reveal the evolutionary history of the reed warbler populations.