Context. Some populations of introduced species cause significant undesirable impacts but can also
act as reservoirs for genetic diversity. Sambar deer (Cervus unicolor) are ‘Vulnerable’ in their native
range and invasive in Australia and New Zealand. Genetic data can be used to determine whether
these introduced populations might serve as genetic reservoirs for declining native populations and
to identify spatial units for management. Aims. We aimed to identify the provenance of sambar deer
in Australia and New Zealand, and to characterise their genetic diversity and population structure.
Methods. We used mitochondrial control region sequences and 18 nuclear microsatellite loci of 24
New Zealand and 63 Australian sambar deer collected across continuous habitat in each location.
We estimated genetic diversity and population differentiation by using pairwise FST, AMOVA, and
STRUCTURE analyses. We compared our data with 27 previously published native and invasive range
sequences to identify phylogenetic relationships. Key results. Sambar deer in Australia and New
Zealand are genetically more similar to those in the west of the native range (South and Central
Highlands of India, and Sri Lanka), than to those in the east (eastern India, and throughout Southeast
Asia). Nuclear genetic diversity was lower than in the native range; only one mitochondrial haplotype
was found in each introduced population. Australian and New Zealand sambar deer were genetically
distinct but there was no population structure within either population. Conclusions. The genetic
differences we identified between these two introduced populations at putatively neutral loci
indicate that there also may be underlying diversity at functional loci. The lack of population genetic
structure that we found within introduced populations suggests that individuals within these popula-
tions do not experience barriers to dispersal across the areas sampled. Implications. Although
genetic diversity is reduced in the introduced range compared with the native range, sambar deer
in Australia and New Zealand harbour unique genetic variants that could be used to strengthen
genetic diversity in populations under threat in the native range. The apparent high levels of gene
flow across the areas we sampled suggest that localised control is unlikely to be effective in Australia
and New Zealand
