Genetic and demographic vulnerability of adder populations: Results of a genetic study in mainland Britain

Research output: Contribution to journalArticle


Genetic factors are often overlooked in conservation planning, despite their importance in small isolated populations. We used mitochondrial and microsatellite markers to investigate population genetics of the adder (Vipera berus) in southern Britain, where numbers are declining. We found no evidence for loss of heterozygosity in any of the populations studied. Genetic diversity was comparable across sites, in line with published levels for mainland Europe. However, further analysis revealed a striking level of relatedness. Genetic networks constructed from inferred first degree relationships suggested a high proportion of individuals to be related at a level equivalent to that of half-siblings, with rare inferred full-sib dyads. These patterns of relatedness can be attributed to the high philopatry and low vagility of adders, which creates high local relatedness, in combination with the polyandrous breeding system in the adder, which may offset the risk of inbreeding in closed populations. We suggest that reliance on standard genetic indicators of inbreeding and diversity may underestimate demographic and genetic factors that make adder populations vulnerable to extirpation. We stress the importance of an integrated genetic and demographic approach in the conservation of adders, and other taxa of similar ecology.


  • Sarah Ball
  • Nigel Hand
  • Faye Willman
  • Christopher Durrant
  • Tobias Uller
  • Katja Claus
  • Joachim Mergeay
  • Dirk Bauwens
  • Trenton W.J. Garner
External organisations
  • Zoological Society of London
  • University College London
  • University of Oxford
  • University of Antwerp
  • Research Institute for Nature and Forest
  • Central Ecology
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Evolutionary Biology
Original languageEnglish
Article numbere0231809
JournalPLoS ONE
Issue number4
Publication statusPublished - 2020
Publication categoryResearch