Does hybridization with an invasive species threaten Europe’s most endangered reptile? Genomic assessment of Aeolian lizards on Vulcano island
Josephine R. Paris,
Gentile Francesco Ficetola,
Joan Ferrer Obiol,
Iolanda Silva-Rocha,
Miguel Angel Carretero,
Daniele Salvi
Affiliations
Josephine R. Paris
Department of Health, Life and Environmental Sciences, University of L’Aquila, Coppito, Italy; Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
Gentile Francesco Ficetola
Department of Environmental Science and Policy, University of Milan, Milano, Italy; Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, Laboratoire d’Ecologie Alpine (LECA), Grenoble, France; Corresponding author
Joan Ferrer Obiol
Department of Environmental Science and Policy, University of Milan, Milano, Italy
Iolanda Silva-Rocha
CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Capus de Vairão 4485-661 Vairão, Portugal
Miguel Angel Carretero
CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Capus de Vairão 4485-661 Vairão, Portugal; Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão 4485-661 Vairão, Portugal
Daniele Salvi
Department of Health, Life and Environmental Sciences, University of L’Aquila, Coppito, Italy; Corresponding author
Summary: Interspecific hybridization can be consequential for insular species. The Critically Endangered Aeolian wall lizard, Podarcis raffonei, severely declined due to interactions with the invasive Italian wall lizard, Podarcis siculus. The largest population of P. raffonei survives on a narrow peninsula (Capo Grosso) that is mildly connected to the island of Vulcano, which has been entirely invaded by P. siculus. Recent observation of individuals with an intermediate phenotype raised concern over the risk that hybridization might swamp this last stronghold. We genetically characterized lizards from Vulcano, considering individuals showing multiple phenotypes (native, invasive, and “intermediate”). Hybridization rate was low (∼3%), with just two F1 hybrids and two backcrosses, suggesting that hybridization does not currently represent a major threat. However, we identified low genetic diversity, a small effective population size, and a low Ne/Nc ratio. Management strategies are urgently needed to control invasive species and maintain the genetic diversity of P. raffonei.
