Evolutionary Biogeography of New Zealand

by

Hamish G. Spencer, Nicolas J. Rawlence

• LAST REVIEWED: 15 August 2022
• LAST MODIFIED: 22 April 2020
• DOI: 10.1093/obo/9780199941728-0125

Introduction

Ever since the first western scientists visited Aotearoa New Zealand, biologists have been fascinated by the relationships of New Zealand’s biota to that of the rest of the world. (Aotearoa is the usual Māori name for New Zealand; increasingly, the combination Aotearoa New Zealand is also used to refer to the country.) The presence of notable vertebrates (e.g., tuatara), together with a high level of endemism among plants and invertebrates, was clearly a consequence of the islands’ long geological isolation. However, some elements showed clear affinities with taxa elsewhere—Australia and South America, most prominently. Explaining the evolutionary history of this biodiversity was (and is) an attractive driver for much scientific research. Leading vicariance biogeographer Gareth Nelson even claimed that, from a biogeographic standpoint, New Zealand’s biota was the most important in the world: “Explain New Zealand and the world falls into place around it.” Biologist Jared Diamond described New Zealand’s biodiversity as “the nearest approach to life on another planet.” Part of the reason for New Zealand providing so many biogeographic puzzles and exemplars lies in its active geology, a consequence of its position across the boundary of the Australian and Pacific tectonic plates. Unlike most oceanic islands, New Zealand comprises continental crust, remnants of the now largely submerged continent of Zealandia, which extended beyond present-day New Caledonia to the north, Campbell Island to the south, and Chatham Island to the east. In addition, New Zealand has periodically been subject to marine transgressions of varying degree. This geological history has been conducive to in situ geographical speciation, which has made a major contribution to the current levels of biodiversity, with some groups (e.g., punctid landsnails) remarkably speciose. In addition, the fluctuations in sea level have resulted in an excellent marine fossil record (especially in the Cenozoic era). Quaternary ice ages rapidly changed the New Zealand landscape, repeatedly isolating plants and animals in glacial refugia. Finally, the late arrival of humans in Aotearoa New Zealand resulted in widespread extinctions and biological turnover events. New Zealand’s biodiversity is enhanced by its geographical and consequent climatic range. It consists of a chain of islands extending over ~2800 km, from the subtropical Kermadec Islands in the north, via the three main temperate islands (North, South and Stewart Islands) to a number of subantarctic islands (Snares, Auckland, Bounty, Antipodes and Campbell Islands) in the south, as well as the Chatham Islands in the east. The politically Australian subantarctic Macquarie Island is often also considered biogeographically neozelanic. Various debates in biogeography, most notably the disputes between the dispersalist school and the vicariance-panbiogeographers, have cited New Zealand examples and, indeed, involved New Zealand scientists. Obviously, the arguments for and against so called “Oligocene drowning”—whether or not all of proto-New Zealand was submersed ~27 million years ago (mya)—involved New Zealand scientists and examples. More generally, the resolution of this latter debate illustrated how to evaluate dispersalist and vicariance hypotheses using modern techniques and integrative approaches.

Documenting the Biota

One of the first steps in understanding New Zealand’s biogeographic history is, of course, the documentation of its biota. Since the 19th century, numerous biologists, both professional and amateur, have been involved in recording and naming species, as well as revising their classification to reflect their evolutionary relationships. Today, New Zealand has, by world standards, a remarkably well-documented biota, even if a large proportion of species, especially invertebrates, remain unnamed. Many animal and plant groups also have particular checklists, but these are not listed here. Plants were first addressed comprehensively in Hooker 1864 and later in the multivolume set Allan, et al. 1961–2000. Buller 1873 documented the avifauna, but it was Oliver 1930 that first gave serious scientific attention to New Zealand’s species. The Mollusca were monographed in Suter 1913; Solem, et al. 1981 points out the remarkable sympatric diversity in the landsnail microfauna. Buckley, et al. 2015 gives an overview of the insect fauna. Hutton 1904 attempted a full list of the animal species known from New Zealand; in this century Gordon 2009–2012 lists all the species represented in the biota, living and extinct, named and unnamed, requiring three volumes. Chilton 1909 is critical in understanding New Zealand’s subantarctic biota.

• Allan, H. H., L. B. Moore, E. Edgar, et al. 1961–2000. Flora of New Zealand. 5 vols. Wellington, NZ: Government Printer, Botany Division, D.S.I.R. and Manaaki Whenua Press.

  Different authors contributed detailed descriptions of New Zealand’s flora to different volumes in this five-volume work, with each volume covering a different taxonomic group of vascular plants. Originally printed, but now also available electronically online; further volumes covering lichens, liverworts, and hornworts are available only online.

• Buckley, T. R., M. Krosch, and R. A. B. Leschen. 2015. Evolution of New Zealand insects: Summary and prospectus for future research. Austral Entomology 54.1:1–27.

  DOI: 10.1111/aen.12116

  An overview of the evolution, especially the biogeography, of New Zealand’s insect fauna. Notes the low diversity of some groups that are often very speciose overseas, as well as unexpected radiations in others. The paper argues for the importance of Quaternary glaciations in generating present-day patterns.

• Buller, W. L. 1873. A history of the birds of New Zealand. London: John Van Voorst.

  This seminal publication (and the second edition in 1888, supplement in 1905; and third edition in 1967[Christchurch, NZ: Whitcombe and Tombs]) with lavish paintings by J. G. Keulemans, was the first popular book on the avian biodiversity of New Zealand.

• Chilton, C., ed. 1909. The subantarctic islands of New Zealand, Vol I. and II. Christchurch, NZ: Philosophical Institute of Canterbury.

  This two-volume treatise reports on the 1907 expedition to the subantarctic Auckland and Campbell Islands, and reports on the geology, zoology, and botany of the islands. This seminal publication involved many of the leading scientists of the day.

• Gordon, D. P., ed. 2009–2012. New Zealand inventory of biodiversity. Volume 1, Kingdom Animalia: Radiata, Lophotrochozoa and Deuterostomia; Volume 2, Kingdom Animalia: Chaetognatha, Ecdysozoa, Ichnofossils; Volume 3, Kingdoms Bacteria, Protozoa, Chromista, Plantae, Fungi. Christchurch, NZ: Canterbury Univ. Press.

  A truly herculean effort to list all the species, described and undescribed, from New Zealand. Each chapter begins with an overview of the group, including such matters as the numbers of species and the degree of endemism, as well as a brief history of the taxonomic study. The proportion of recognized but unnamed species was remarkably high in many “well-known” groups (e.g., molluscs).

• Hooker, J. D. 1864. Handbook of the New Zealand flora: A systematic description of the native plants of New Zealand and the Chatham, Kermadec’s, Lord Auckland’s, Campbell’s and MacQuarrie’s [sic.] Islands. London: Reeve.

  This two-volume compendium, by Darwin’s close ally, was the first to attempt an exhaustive taxonomic description of New Zealand’s plant, algal, lichen, and fungal species.

• Hutton, F. W., ed. 1904. Index faunae Nova-Zealandiae. London: Dulau.

  The first real attempt to list all the native animal species recorded from New Zealand. The Index starts with a general overview, before proceeding to a discussion of the biogeographical affinities of various elements of the fauna, including a discussion of geological and paleontological evidence. Presciently, Hutton noted that there were biogeographical affinities between Australia and South America that were not shared with New Zealand. Available online.

• Oliver, W. R. B. 1930. New Zealand birds. Wellington, NZ: Fine Arts New Zealand.

  Walter Oliver continued the tradition of Buller documenting the evolution, ecology. and taxonomy of the birds of New Zealand. This book (and the extensively revised second edition [Wellington, NZ: A.H. and A.W. Reed] in 1955) became the seminal reference on the taxonomy of New Zealand birds until the Ornithological Society of New Zealand (Birds New Zealand) published taxonomic checklists.

• Solem, A., F. M. Climo, and D. J. Roscoe. 1981. Sympatric species diversity of New Zealand land snails. New Zealand Journal of Zoology 8.4:453–485.

  DOI: 10.1080/03014223.1981.10427971

  New Zealand’s micro-landsnail fauna is perhaps even more remarkable than its better known giant landsnail diversity. Extraordinary radiations within the Charopidae and Punctidae have resulted in >700 species, almost all endemic, and an equally noteworthy degree of sympatry, with >70 species estimated to live in small areas of North Island forest, a number well in excess of the more usual fifteen sympatric species overseas. Available online by subscription or purchase.

• Suter, H. 1913. Manual of the New Zealand Mollusca. Wellington, NZ: John MacKay, Government Printer.

  An historically important attempt to provide descriptions and figures of all the New Zealand molluscs. Suter’s appreciation of the rules of taxonomy means that many of his designations of type species for molluscan genera are relevant to faunas worldwide.