Research Article

Conservation Genetics

, Volume 15, Issue 2, pp 453-468

A 40-year-old divided highway does not prevent gene flow in the alpine newt Ichthyosaura alpestris

  • Jérôme G. PrunierAffiliated withEcosphèreUniversité de Lyon, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, ENTPE, CNRSInstitute of Life Sciences (ISV), Université Catholique de Louvain Email author 
  • , Bernard KaufmannAffiliated withUniversité de Lyon, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, ENTPE, CNRS
  • , Jean-Paul LénaAffiliated withUniversité de Lyon, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, ENTPE, CNRS
  • , Serge FenetAffiliated withUniversité de Lyon, UMR 5205 Laboratoire d’Informatique en Image et Systèmes d’information, Bat. Nautibus, Université Lyon 1, CNRS
  • , François PompanonAffiliated withUniversité Joseph Fourier, Laboratoire d’Ecologie Alpine, CNRS, UMR 5553
  • , Pierre JolyAffiliated withUniversité de Lyon, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, ENTPE, CNRS

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Abstract

Roads are of major concern in conservation biology, as they are known to restrict animal movements through landscape fragmentation, and may therefore impact genetic patterns in native terrestrial organisms. We assessed the effect of two large-scale transportation infrastructures (LTIs), a 40-year-old highway and a 30 year-old high-speed railway, on the spatial genetic structure of the alpine newt Ichthyosaura alpestris, a highly nomadic amphibian. Genetic data were gathered following a targeted individual-based sampling scheme and analysed using both overlay and correlative methods. While simulations suggested that the highway may be old enough for a significant barrier effect to be detected, LTIs were never detected as barriers to gene flow: inferred genetic boundaries rather coincided with transition zones between major landscape entities. Furthermore, spatial principal component analysis, a method designed to reveal cryptic genetic spatial patterns in high gene flow species, counter-intuitively suggested that the highway may act as a potential dispersal corridor in low-quality habitats, thus challenging traditional hypotheses on road impacts in amphibians. Our study showed that considering local interactions between species, infrastructures and landscape-specific characteristics is essential for better understanding the potential impacts of roads on movement patterns in terrestrial organisms.

Keywords

Amphibian Bayesian clustering methods Correlative analyses Landscape genetics Spatial Principal Component Analysis