Population structure and biogeography of Hemiphaga pigeons (Aves: Columbidae) on islands in the New Zealand region

Abstract

Aim The New Zealand avifauna includes lineages that lack close relatives elsewhere and have low diversity, characteristics sometimes ascribed to long geographic isolation. However, extinction at the population and species levels could yield the same pattern. A prominent example is the ecologically important pigeon genus Hemiphaga. In this study, we examined the population structure and phylogeography of Hemiphaga across islands in the region.Location New Zealand, Chatham Islands and Norfolk Island.Methods Mitochondrial DNA was sequenced for all species of the genus Hemiphaga. Sixty-seven individuals from mainland New Zealand (Hemiphaga novaeseelandiae novaeseelandiae), six of the Chatham Islands sister species (Hemiphaga chathamensis), and three of the extinct Norfolk Island subspecies (Hemiphaga novaeseelandiae spadicea) were included in this study. Novel D-loop and cytochrome b primers were designed to amplify DNA from museum samples. Additionally, five other mitochondrial genes were used to examine placement of the phylogenetic root.Results Analyses of mitochondrial DNA sequences revealed three Hemiphaga clades, consistent with the allopatric populations of recognized (sub)species on oceanic islands. Of the 23 D-loop haplotypes among 67 New Zealand pigeons (Hemiphaga n. novaeseelandiae), 19 haplotypes were singletons and one haplotype was common and widespread. Population genetic diversity was shallow within and between New Zealand populations, indicating range expansion with high inter-population exchange. Tentative rooting of the Hemiphaga clade with cyt b data indicates exchange between mainland New Zealand and the Chatham Islands prior to colonization of Norfolk Island. We found low genetic divergence between populations on New Zealand, the Chatham Islands and Norfolk Island, but deep phylogenetic divergence from the closest living relatives of Hemiphaga. Main conclusionsThe data are consistent with the hypothesis of population reduction during the Pleistocene and subsequent expansion from forest refugia. Observed mobility of Hemiphaga when feeding helps explain the shallow diversity among populations on islands separated by many hundreds of kilometres of ocean. Together with comparison of distribution patterns observed among birds of the New Zealand region, these data suggest that endemicity might represent not long occupancy of an area, but descent from geologically recent colonizations. We consider the role of lineage pruning in creating the impression of old endemicity.

Postglacial expansion and not human influence best explains the population structure in the endangered kea (Nestor notabilis)

“…) that exhibited a pattern of low diversity, shallow phylogenetic network and high connectivity within mainland New Zealand, consistent with a severe bottleneck at the onset of the glaciations and rapid recent range expansion (Rogers & Harpending ; Goldberg et al . ). However, the absence of a star‐like network characteristic of rapid population expansion (Slatkin & Hudson ) is rather surprising as the contemporary widespread distribution of kea in the South Island supports some range expansion after the Pleistocene.…”

“…Here, we have confirmation that the recent evolutionary history of kea is very similar to the New Zealand pigeon H. n. novaeseelandiae (Goldberg et al . ) and Emeus crassus (Bunce et al . ) that exhibited a pattern of low diversity, shallow phylogenetic network and high connectivity within mainland New Zealand, consistent with a severe bottleneck at the onset of the glaciations and rapid recent range expansion (Rogers & Harpending ; Goldberg et al .…”

“…) and many avian species, among them the pigeon Hemiphaga novaseelandiae novaseelandiae (Goldberg et al . ), moas such as Megalapteryx sp . (Bunce et al .…”

Genetic structure of the critically endangered Red‐headed Wood Pigeon Columba janthina nitens and its implications for the management of threatened island populations

“…These differences are a little higher than that between the two sister species: the New Zealand Pigeon Hemiphaga novaeseelandiae and the Chatham Pigeon Hemiphaga chathamensis (1.3% in cytochrome‐ b region and 2.9% in control region; Goldberg et al . ). Considering the strong genetic differentiation and geographical isolation, the nominate Japanese Wood Pigeon and the Red‐headed Wood Pigeon may be regarded as separate species.…”

Closing the gap: Avian lineage splits at a young, narrow seaway imply a protracted history of mixed population response

“…Minimum‐spanning and median‐joining networks (Bandelt, Forster, & Röhl, ) were inferred for Weka haplotypes in PopArt (Leigh & Bryant, ) and colour‐edited in Adobe Illustrator. We downloaded published mtDNA Control Region sequence for seven other New Zealand bird taxa that span the Cook Strait (Dussex, Sainsbury, Moorhouse, Jamieson, & Robertson, ; Goldberg, Trewick, & Powlesland, ; Miller & Lambert, ; Robertson, Steeves, et al., ; Shepherd et al., ; Trewick & Olley, ) and inferred haplotype networks for each using minimum‐spanning and median‐joining networks.…”