Roberta D’Archino1, Wendy A. Nelson 1,2, Kate F. Neill1, Ngāti Kuri3
1National Institute of Water and Atmospheric Research, Private Bag 14901, Wellington 6241, New Zealand
2School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
3Ngāti Kuri, 5399 Main North Road, Nga Taki, RD 4 Kaitaia 0484, New Zealand
Rangitāhua/Kermadec Islands are a subtropical volcanic archipelago situated in the South Pacific Ocean, halfway between New Zealand and Tonga. Rangitāhua hosts New Zealand’s largest marine reserve and is considered one of the most pristine ecosystems on Earth. The macroalgal flora, still not fully described, has strong affinities with other warm-water regions of the Pacific and Indian Oceans. Of 157 species previously recorded, more than half are not found in New Zealand mainland. In November 2021, the first expedition to the islands as part of a five-year research programme, Te Mana o Rangitāhua, enabled targeted macroalgal collections associated with different habitats. The programme is led by Ngāti Kuri, (iwi (tribe) with mana moana) and Auckland Museum, and through a holistic approach combining indigenous knowledge and science, aims to understand the biodiversity and ecosystems of Rangitāhua from land to sea and identify indicators of ecosystem change.
Preliminary investigations, with over 160 samples sequenced, uncovered both new taxa, and new understanding of genera and species already recorded. For example, samples identified in the field as Coelarthrum or Botryocladia, genera with a very distinctive morphology, as well as some samples of turfing red algae, do not align with available data for currently recognised genera. High diversity has been found in the red algae Nemaliales and crustose coralline algae, in the brown algae Dictyotales as well in the green algae. The process of naming the new taxa is bringing together taxonomists and iwi and it will be guided by mātauranga Māori (Māori knowledge).