Post-epizootic salamander persistence in a disease-free refugium suggests poor dispersal ability of Batrachochytrium salamandrivorans

Sci Rep. 2018 Feb 28;8(1):3800. doi: 10.1038/s41598-018-22225-9.

Abstract

Lack of disease spill-over between adjacent populations has been associated with habitat fragmentation and the absence of population connectivity. We here present a case which describes the absence of the spill-over of the chytrid fungus Batrachochytrium salamandrivorans (Bsal) between two connected subpopulations of fire salamanders (Salamandra salamandra). Based on neutrally evolving microsatellite loci, both subpopulations were shown to form a single genetic cluster, suggesting a shared origin and/or recent gene flow. Alpine newts (Ichthyosaura alpestris) and fire salamanders were found in the landscape matrix between the two sites, which are also connected by a stream and separated by no obvious physical barriers. Performing a laboratory trial using alpine newts, we confirmed that Bsal is unable to disperse autonomously. Vector-mediated dispersal may have been impeded by a combination of sub-optimal connectivity, limited dispersal ability of infected hosts and a lack of suitable dispersers following the rapid, Bsal-driven collapse of susceptible hosts at the source site. Although the exact cause remains unclear, the aggregate evidence suggests that Bsal may be a poorer disperser than previously hypothesized. The lack of Bsal dispersal between neighbouring salamander populations opens perspectives for disease management and stresses the necessity of implementing biosecurity measures preventing human-mediated spread.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chytridiomycota / physiology*
  • Multigene Family / genetics
  • Refugium*
  • Urodela / genetics
  • Urodela / microbiology*