A molecular investigation into the origin and relationships of karaka/kōpi (Corynocarpus laevigatus) in New Zealand

Abstract

Corynocarpus is a small, morphologically and phylogenetically isolated genus of trees from the southwest Pacific. We examined the phylogeny of Corynocarpus using the nuclear WAXY and ITS loci. Our molecular dating, when examined in combination with other published molecular dating studies, indicates that the origin of the genus and the arrival of Corynocarpus in New Zealand are likely to be much more recent than previously suggested. A second focus of our study was to investigate patterns of pre-European putative translocation of C. laevigatus (karaka, kōpi) by Māori throughout New Zealand using diversity at these two loci. Our New Zealand-wide sampling revealed the distinctiveness of specimens from the Three Kings Islands at both loci, precluding the Three Kings Islands as the source population for translocated C. laevigatus. However, the low level of sequence variation at these loci prevented further insight into the human-mediated dispersal of this species.

Keywords:

• Corynocarpus
• dispersal
• karaka
• molecular dating
• molecular phylogeny
• New Zealand
• nuclear DNA sequence markers
• translocation

Acknowledgements

We would like to acknowledge all iwi and hapū who granted us permission to collect from within their rohe, in particular those who contacted and/or met with us in person: the Hokotehi Moriori Trust Board, Ngāti Kuri, Te Aupouri, Tiakina te Taiao, Rangitāne, Te Atiawa, Ngāi Tahu, Ngātiwai, Patuharakeke Trust, Ngā Puhi, Te Rarawa and Ngā Rauru. Samples were collected under Department of Conservation permits WA-23814-FLO, BOP-23814-FLO, TT-23661-FLO, NO-233360-FLO and Otari Wilton's Bush permit 145. We thank Rewi Elliot and Eleanor Burton (Otari Wilton's Bush, Wellington), Murray Thacker (Okains Bay), Kevin Matthews (Kaitaia), Barbara and Dan Ramsden (Moanaroa), Janene Collings, Jeremy Rolfe and David Havell (Department of Conservation), Trevor Thompson, Bill Wallace, Greg Blunden (QEII Trust), Tricia Aspin and Leon Perrie for assistance with sample collection. We also thank Leon Perrie, Jill Rapson and an anonymous reviewer for comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by the Royal Society of New Zealand’s Marsden Fund (contract number MAU0709). RAA acknowledges financial support from a Massey University Doctoral Scholarship, JP Skipworth Scholarship for Plant Biology, Hokotehi Moriori Trust Board, Intellectual Property in Cultural Heritage (IPinCH) and the Allan Wilson Centre and supervision from Nick Roskruge. LDS acknowledges support from a Rutherford Discovery Fellowship from the Royal Society of New Zealand (contract number RDF-MNZ1201).