New Zealand: native wildlife on the edge

Coming clean

OK, I’ll admit it, my earlier post about my attitude to New Zealand was a tad economical with the truth.  I wasn’t, from my teenage years, quite as ignorant about Aotearoa as I might have implied, nor was I totally indifferent to it.  In fact, nice people though they probably were – they play cricket, after all – I felt distinctly ambivalent towards New Zealanders on the grounds that they never had much in the way of wildlife, and had done a pretty good job of wiping out what they had.

This was, of course, a totally unfair – and somewhat hypocritical – assessment.

Evolution in isolation

New Zealand was, until the Polynesian settlers turned up less than a thousand years ago, a regular Billy No-Mates.   The landmass that we now know as New Zealand split away from Gondwanaland – the ancient supercontinent that incorporated present-day South America, Africa, Arabia, Madagascar, India, Australia, and Antarctica – around 85 million years ago.  Since then it’s been on its own, largely isolated from the evolutionary forces that shaped life on the rest of the planet.

As a result there are virtually no native mammals in New Zealand, just a couple of species of bat whose ancestors must have flown there, and marine mammals such as seals, dolphins and whales.

File:Kokako.jpg
Kokako. : By Matt Binns (originally posted to Flickr as Kokako) [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)%5D, via Wikimedia Commons

With birds, of course, it’s an entirely different matter.  They could fly in to colonise the ancient landmass, at which point evolution did its thing.  New arrivals in Aotearoa found few competitors, and multiple niches waiting to be filled.  They adapted accordingly, in a process known to biologists as adaptive radiation, where one species rapidly evolves into many species that may live in different environments.  Soon New Zealand had a unique, vibrant bird life, such as the spectacular kokako.

The lack of mammalian predators meant that many birds took a relaxed attitude to personal safety, with some giving up the ability to fly altogether in favour of a more laid back terrestrial lifestyle.  Before humans arrived, a quarter of New Zealand’s land and freshwater birds were flightless, and many that could fly weren’t very good at it.  The only threat to them was predatory birds, and their defensive strategies for avoiding these amounted to little more than hiding in plain site – camouflage, and standing motionless when danger threatened – or maybe running away, albeit quite slowly.   Which was all fine and dandy, until man showed up.

Man turns up, extinction stalks the land

When the Polynesian ancestors of the Māori landed on New Zealand, native birds soon found themselves on the menu.  Nothing in their experience prepared them for the arrival of this tool-bearing super-predator, and pretty soon extinction stalked the land.  Early victims included the moa, massive flightless birds up to two metres tall, like

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ostriches on steroids.  They were lumbering, tasty vegetarians and they didn’t stand a chance when the Maori turned up.  Their flesh was eaten, their feathers and skins were made into clothing. The bones were used for fish hooks and pendants.  Within a couple of centuries they were all gone.

The Maori also brought with them – probably accidentally – the Polynesian rat, and pretty soon after New Zealand’s third native species of terrestrial mammal, the greater short-tailed bat, was extinct on the main islands.  This impact of an introduced mammal on the New Zealand’s native fauna was a sign of things to come.

Europeans don’t do things by halves.  They brought with them a whole host of pest species.  Possums were imported from Australia to create a fur industry, but have since run amok.  There are reckoned to be 65 million of the little buggers, around 20 for each human New Zealander.  They decimate forest and woodland, taking mainly leaves, but also buds, flowers, fruit and seeds from the tallest tree tops.  On the ground they eat seedlings, saplings and sometimes bark.  Possums also eat insects, bats, birds and their eggs and nestlings. They drive native animals out of their dens and nesting sites.

Cats have also run wild since their introduction in the nineteenth century, and are a menace to native wildlife.  Equally deadly is the stoat, which was imported from Britain in the 1870s to control rabbits that the Europeans had already introduced (oops!)  Cats, stoats and rats introduced from Europe have between them been responsible for

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multiple extinctions of New Zealand’s native birds.  It’s a depressing story, and the fact that the wildlife of other isolated islands across the globe has suffered a similar fate doesn’t make it any easier to bear.  It was for this reason that I was reluctant to visit New Zealand.  It seemed impossible to contemplate deriving pleasure from visiting a land where so much had been lost.  And yet …

A glimmer of hope

… and yet, on closer inspection, New Zealand as a nation is stepping up the plate.   What’s gone is gone, there’s no chance of doing a Jurassic Park and bringing back to life the birds that have gone extinct, but it appears that great efforts are being made by a country with a small population to preserve what’s left.  I’ve found references to some excellent conservation initiatives that give a glimmer of hope for the future.  I’m not so naïve as to expect that success is guaranteed; there will be setbacks and disappointments, but at least they are making an effort even though it would plainly be easier – and cheaper – not to bother.  On that basis, New Zealand’s definitely worth a visit.

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