Invasion genomics of the alpine newt in Britain reveal a complex history
of introductions and translocations
Abstract
The spread of invasive species to regions outside of their typical,
native range has been fuelled by globalization and trade, with
human-facilitated introductions being a primary driver of invasion by
non-native species. The alpine newt, Ichthyosaura alpestris is native to
mainland Europe, and has become well-established at several locations
across the UK, with a pattern of invasion in the UK suggesting both
primary introductions from its native range, and secondary
translocations from established sites. We sampled 95 individuals from 23
ponds in 11 sites across the UK and obtained their genomic SNP (Single
Nucleotide Polymorphisms) data from ddRAD-sequencing to answer questions
about the invasion history of these UK non-native amphibians. In
conjunction with these genomic tools, anecdotal evidence is also used to
better understand the pattern of invasion and subsequent spread of
alpine newts across the country. Our results provide an insight into the
genetic variation within these populations, with strong population
structure among sites and ponds within a site. Population structure
analyses also provide evidence for human-assisted movement of newts
within the UK and the results are consistent with multiple independent
introductions. Such findings support the idea that human-mediated
translocation plays a central role in the movement of alpine newts
around the UK. This research illustrates how genomics can be used in
conjunction with historical data to better understand the invasion
history of non-native organisms.