Data from: A genetic assessment of the human-facilitated colonization history of black swans in Australia and New Zealand

Movement of species beyond their indigenous distribution can fundamentally
alter the conservation status of the populations involved. If
introductions are human-facilitated, introduced species could be
considered pests. Characterizing the colonization history of introduced
species can, therefore, be critical to formulating the objectives and
nature of wildlife management strategies. The black swan (Cygnus atratus)
is native to Australia but is considered a reintroduced species in New
Zealand, where the endemic population was reported extinct during the 19th
century. After the re-introduction of a small number of individuals from
Australia, the New Zealand population expanded unexpectedly rapidly, which
was attributed to simultaneous waves of migration from Australia. An
alternative, but hitherto unformalized, hypothesis is that local extant
populations remained and admixed with introduced individuals. To
contribute to our understanding of the reintroduction history of the
species, we investigated dispersal patterns and demographic histories of
seven populations from Australia and New Zealand, using population genetic
inferences from a microsatellite dataset. Our results on genetic
structure, dispersal rates, and demographic histories provide mixed
evidence on the origin of New Zealand black swans. The hypothesis that
reintroduced individuals mixed with remaining local individuals and that
the subsequent dramatic population expansion may have been due to genetic
rescue of the inbred indigenous population cannot be discarded and needs
further investigation.