Connectivity of Alpine newt populations (Ichthyosaura alpestris) exacerbates the risk of Batrachochytrium salamandrivorans outbreaks in European fire salamanders (Salamandra salamandra)

Abstract The pathogenic chytrid fungus Batrachochytrium salamandrivorans ( Bsal ) was introduced from Asia to Europe, most likely via the pet trade. It is currently causing a severe local decline in populations of European fire salamanders Salamandra salamandra ). Laboratory tests confirmed that all infected individuals succumbed disease within two weeks. Furthermore, mass mortality events wild were observed Germany, Belgium and Netherlands. Some newt species, including Alpine Ichthyosaura alpestris ), can also become with . However, they seem be ‘tolerant’ often survive disease, but maintain an infectious load, which could spread among connected populations. is, therefore, hypothesized this species functions as vector threatens syntopic susceptible such salamander. To assess risk newts vectors for , we sampled 233 50 sites 2017 performed genetic population connectivity analysis using microsatellites. results showed are not spatially structured, suggesting high gene flow across study area. Tests 150 other five individuals. Infected thus function reservoirs it through dispersal. As result, salamander declines region further exacerbated by