Population connectivity across a highly fragmented distribution: Phylogeography of the Chalcophaps doves

<p><i>Chalcophaps</i> is a morphologically conserved genus of ground-walking doves distributed from India to mainland China, south to Australia, and across the western Pacific to Vanuatu. Here, we reconstruct the evolutionary history of this genus using DNA sequence data from two nuclear genes and one mitochondrial gene, sampled from throughout the geographic range of <i>Chalcophaps</i>. We find support for three major evolutionary lineages in our phylogenetic reconstruction, each corresponding to the three currently recognized <i>Chalcophaps </i>species. Despite this general concordance, we identify discordant mitochondrial and nuclear ancestries in the subspecies <i>C. longirostris timorensis, </i>raising further questions about the evolutionary history of this Timor endemic population. Within each of the three species, we find evidence for isolation by distance or hierarchical population structure, indicating an important role for geography in the diversification of this genus. Despite being distributed broadly across a highly fragmented geographic region known as a hotspot for avian diversification, the <i>Chalcophaps</i> doves show modest levels of phenotypic and genetic diversity, a pattern potentially explained by strong population connectivity owing to high overwater dispersal capability.</p>