The vegetation, flora, mycobiota and vertebrate fauna of Motuhinahina, a limestone island in Te Whanga Lagoon, Rēkohu / Wharekauri / Chatham Island

Peter J. de Lange^1,*, Rowan K. Scott², Campbell J. James¹, Dayna J. M. McKenzie¹, Marleen Baling¹, Rachel Klein¹, Karla Butcher³, Amelia Tapp¹, Sophie Rear¹, Andrew Marshall¹, Rob Chappell⁴, Hamish Tuanui-Chisholm⁵

Affiliation:
¹ School of Environmental and Animal Sciences, Unitec, Private Bag 92025, Victoria Street West, Auckland 1142, New Zealand.
² NorthTec, Private Bag 9019, Whangarei 0148, New Zealand.
³ University of Auckland, Thomas Building, 44 Symonds Street, Grafton Auckland 101, New Zealand.
⁴ 200 Mannion Road, Wyuna Bay, Coromandel 3581, New Zealand
⁵ 1007 Waitangi-Tuku Road, Chatham Islands 8016, New Zealand.
^* Corresponding author: pdelange@unitec.ac.nz

Received: 3 September 2025 | Accepted: 13 November 2025 | Published: xx
Associate Editor: Lilith Fisher
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Abstract
Motuhinahina (0.454 ha, 3 m a.s.l., -43.896777, -176.488079) is the largest of the 21 limestone islands and rock stacks present along the western side of Te Whanga, Rēkohu / Wharekauri / Chatham Island. The island is an example of a very uncommon terrestrial ecosystem on the Chatham’s namely ‘karst islands, islets and rock stacks’. The island is notable for its role as a ‘safe’ refuge and nesting site for papua | Chatham Island shag (Leucocarbo onslowi) and kawau o Rangihaute | Pitt Island shags (Phalacrocorax featherstoni), and for having a key population of waiu-atua | shore spurge (Euphorbia glauca), a seriously threatened species on the Chatham Islands, and in decline on the main islands of Aotearoa / New Zealand. In this paper, we document some of the biota of Motuhinahina. For the flora and mycobiota we report 136 taxa present from 78 families (one chromist (brown seaweed), four algal, 12 bryophyte, six pteridophyte (Polypodiopsida), 38 Angiosperm (flowering plant), seven fungal and ten lichenized mycobiota) and 126 genera (one chromist (brown seaweed), four algal, 14 bryophyte, seven pteridophyte, 77 flowering plants, eight fungal and 15 lichenized mycobiont). Fourteen bird species (11 indigenous/endemic, and three naturalised) are also reported. Puhina / kekeno / New Zealand fur seals (Arctocephalus forsteri) are reported to be increasing in numbers and breeding on the island. Six vegetation associations and landforms are described and mapped using the field-based method published by Atkinson in 1985. Two flowering plants, Centipeda minima subsp. minima and Lachnagrostis pilosa subsp. nubifera, and one lichen, Flavoplaca mereschkowskiana, are either new records for the Chatham Islands or Aotearoa / New Zealand as a whole. Motuhinahina has huge potential as a secure site to establish several Chatham Islands ornithocoprophilous endemics.

Cite as
de Lange, P. J., Scott, R. K., James, C. J., McKenzie, D. J. M., Baling, M., Klein, R., Butcher, K., Tapp, A., Rear, S., Marshall, A., Chappell, R., Tuanui-Chisholm, H. (in press). Observations of avifauna on Rēkohu / Wharekauri / Chatham Island, Chatham Islands group, in February 2023. Perspectives in Biodiversity, 4