Data from: Shared genetic diversity across the global invasive range of the Monk parakeet suggests a common restricted geographic origin and the possibility of convergent selection

While genetic diversity is hypothesized to be an important factor
explaining invasion success, there is no consensus yet on how variation in
source populations or demographic processes affects invasiveness. We used
mitochondrial DNA haplotypic and microsatellite genotypic data to
investigate levels of genetic variation and reconstruct the history of
replicate invasions on three continents in a globally invasive bird, the
monk parakeet (Myiopsitta monachus). We evaluated whether genetic
diversity at invasive sites could be explained by (i) the native source
populations from which they were derived and (ii) demographic bottlenecks
during introduction. Genetic data indicated a localized source area for
most sampled invasive populations, with limited evidence for admixing of
native source populations. This pattern largely coincides with historical
data on pet trade exports. However, the invasive populations are
genetically more similar than predicted from the export data alone. The
extent of bottleneck effects varied among invasive populations. The
observed low genetic diversity, evidence of demographic contraction and
restricted source area do not support the hypothesis that invasion is
favoured by the mixing and recombining of genetic variation from multiple
source populations. Instead, they suggest that reduced genetic variation
through random processes may not inhibit successful establishment and
invasion in this species. However, convergent selection across invasive
sites could also explain the observed patterns of reduction and similarity
in genetic variation and/or the restricted source area. In general, the
alternative explanation of intraspecific variation in invasive potential
among genotypes or geographic areas is neglected, but warrants more
attention as it could inform comparative studies and management of
biological invaders.