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No. 3207:
New Zealand's Ecosystem

by Andy Boyd

Today, what once was. The University of Houston presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

What weighs 900 pounds, has four legs, four wings, and is yellow all over? The answer, of course, is two 450-pound canaries.

Canaries   Photo Credit: pxhere

The joke works because the thought of a 450-pound bird of any kind is outrageous. Or is it? At one time flightless birds standing twice as tall as humans and weighing over 500 pounds wandered the earth. And we needn't look back to the time of the dinosaurs. Two hundred years before Christopher Columbus sailed the ocean blue, settlers from Polynesia found their way to the two great land masses we today call New Zealand. The settlers, known as the as the Maori, encountered an estimated 58,000 of the birds, known as moa. Yet as big as the birds were, they were both unfamiliar with predators and a good source of meat. By the time Columbus did set sail, the moa had been hunted to extinction. And it was only a hint of the changes to come.

Moa   Photo Credit: Wikipedia

New Zealand became separated from other land masses some 82 million years ago, thus allowing it to develop its own unique ecosystem; an ecosystem free of large land predators. The only terrestrial mammals were bats. Birds ruled the roost. So when non-native land animals were introduced, the consequences were devastating. Beginning in the late eighteenth century, British colonists imported an array of animals. Rabbits were brought in as a source of food, but soon escaped and began breeding like, well, rabbits. To combat the exploding rabbit population, ferrets, stoats, and weasels were brought in. But these predators took a liking to local bird eggs. So did the burgeoning rat and possum populations - the latter introduced for commercial fur trade. Native birds began to disappear. To this day many forests remain devoid of birdsong.

The highly intelligent and endangered Kea
The highly intelligent and endangered Kea   Photo Credit: Flickr

New Zealand isn't alone in its woes. It's a problem wherever humans go. But New Zealand is uncommon in its concerted desire to restore what once was. Recognizing that native animals are part of its "national identity," in 2016 the country announced a program called Predator Free 2050. The goal is to eradicate the most damaging, non-native predators.

It's a big undertaking that many believe is unachievable. Unless entirely eradicated, predatory species can re-emerge from very small populations. And conventional methods like trapping and poisoning, at least as now practiced, can't scale to a country the same size as Colorado. But looking ahead to 2050, New Zealand is banking on future technology. Part of that technology may include what's known as a gene drive - genetic engineering that kills predatory species by introducing a genetic change handed down through reproduction. Imagine, for example, if all newly born rats were male. It's controversial and even a bit scary. But given their history, I'm sure the New Zealanders will be very careful when they consider turning something loose on the environment.

The flightless kiwi, national bird of New Zealand
The flightless kiwi, national bird of New Zealand   Photo Credit: Wikimedia

I'm Andy Boyd at the University of Houston, where we're interested in the way inventive minds work.

Gene drives can be used for passing on any number of inherited attributes. Here I have mentioned only eradicating predatory species since it is the primary focus of the New Zealand government.

Gene Drive. From the Wikipedia website: Accessed April 16, 2019

Michael Greshko. New Zealand Announces Plan to Wipe Out Invasive Predators. From the National Geographic website: Accessed April 16, 2019

Moa. From the Wikipedia website: Accessed April 16, 2019