[Taxacom] Review of Biogeography and Evolution in New Zealand

John Grehan calabar.john at gmail.com
Tue Feb 7 16:32:16 CST 2017

For those interested, below is the text copy of a review I wrote for the
Botanical Society of Otago Newsletter 80: 13-14.

>From the shores of Gondwana: Review of Biogeography and Evolution in New
Zealand, 2016 by Michael Heads. Taylor & Francis, Boca Raton, Florida. 635

Kaikoura residents recently awoke to see their shoreline raised by two
meters and all sorts of marine life stranded above the water. As sudden and
dramatic as this disruption was to these organisms, it was only one moment
in a long history of millions of years that has moulded the evolution of
plants and animals in New Zealand. This evolutionary history is outlined in
Michael Heads’ new book.

Featuring both geological and biological patterns, this book is unlike any
other, and gives a comprehensive study of animal and plant distributions in
New Zealand. Beginning with a thorough review of the tectonic structure and
history of New Zealand and Zealandia, the book provides a sound platform
upon which to assess the origin and evolution of New Zealand taxa and their
historical connections with the rest of the world.

One of the main differences between this book and just about every other
book on New Zealand’s evolution is that distributions within New Zealand
are shown to be integral parts of global distributions. .  Organisms in New
Zealand are associated with particular geological regions, and these are
related to the localities of sister taxa beyond New Zealand. Distributions
are at the core of this book, and Heads provides innumerable examples of
distributions that either follow particular geological sectors (such as
terranes) or have their boundaries disrupted by tectonic formations (such
as faults or suture zones). Heads argues convincingly, with example after
example, that these distributions are meaningful if they are interpreted as
remnants of ancestral distributions that go back to the Mesozoic, to a time
when neither New Zealand nor Zealandia, existed. This ancient origin for
most, if not all, New Zealand’s endemics may seem unlikely, but it is  in
the tradition of some of New Zealand’s most outstanding early naturalists
and explorers, such as  Ernst Dieffenbach, Thomas Kirk and Leonard

Heads’ book presents extensive biogeographic evidence for the persistence
of New Zealand’s endemic animal and plant distributions from the time of
the dinosaurs - despite all sorts of geological and climatic upheavals.
Yes, there has been a widespread popularization of the notion that New
Zealand must have sunk beneath the sea in the Oligocene, leaving the moa,
kiwi, tuatara and all other species to float or fly across the oceans to
New Zealand after it re-emerged.  But this ‘drowning’ hypothesis never had
any geological or biogeographic credibility, and Biogeography and Evolution
effectively hammers the final nail into the coffin of that somewhat
fanciful notion.

What is particularly remarkable about Biogeography and Evolution is that it
presents an integrated historical model in which animal and plant
distributions are shaped by geological events, when widespread ancestors
fragment or break up over time into a multitude of descendants.. Using
geological data and up-to-date biological studies, Heads explains
 previously puzzling distributions such as disjunctions either side of the
Alpine Fault, distributions between Fiordland and Stewart Island (rather
than Otago and Stewart Island), distributions  among islands off the
northeast of the North Island, and many others.  This model (called
vicariance) also explains why related organisms may only occur in New
Zealand and  in certain other places, such as Tasmania, eastern Australia,
New Caledonia, Lord Howe Island, or Chile, to name a few. There are many
important questions addressed in this book, including why widespread
species are not always found everywhere in New Zealand, or why certain
species stop where they do, even though there is no ecological barrier.
Persistence of life, through its ability to locally disperse and adapt, is
a major evolutionary theme developed in this book that explains why young
volcanic islands or even young volcanoes in New Zealand can harbour ancient

This  book  is really for the curious naturalist – the naturalist who
ponders the deeper question of how New Zealand’s living landscape came to
be, and, for example,  why certain plants or animals  stop at the Moonlight
Tectonic Zone in west Otago, why Hutton’s shearwater (a seabird)  nests
high up in the Kaikoura Mountains, why some plants in Northwest Nelson have
their nearest relatives in coastal New South Wales and New Caledonia, or
why the Titri-Leith-Waitati fault may help explain the origin of endemic
species in Dunedin. No matter what one may think about these distributions,
they do exist and must be addressed in any scientific explanation for New
Zealand’s biology.  Are you a curious naturalist? Do you want answers
instead of paradoxes? Yes? Then this book is for you.

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