Friday, March 15, 2013

unintended consequences.

We humans are not light travelers. We take things with us, leave things behind. We leave our mark like the trails of comets tracing over the earth, the lingering fire of a sparkler as it cuts through a summer night.

Nowhere is this more apparent than in New Zealand, which, according to a recent New Zealand Geographic article, has more introduced species from more sources than perhaps any other country in the world. And we only just got here. Deep in the southern hemisphere, New Zealand was the last country on the planet to be discovered by humans. While early hominids were planting the seeds of agriculture in the Middle East in 8,000 B.C., Maori people first stumbled upon the shores of New Zealand just 800 years ago.

Perhaps because we arrived so late, we are better able to envision what these islands are “supposed” to look like. We can picture an untouched, pre-human New Zealand more vividly than an Egypt free of pyramids or a North America teeming with mammoths. In most places in the world, we left our mark so long ago that we've lost sight of what it “should” look like, but here in New Zealand, paradise lost is still in sight, and there's a growing sentiment that it's our responsibility to return to that state.

Among conservationists in New Zealand, a battle is being waged against invasive and introduced species. The list is long: rats, birds, weasels, cats, goats, fish, deer and countless other creatures were brought to these islands by both Maori and European settlers, some intentionally, others not.

Originally, New Zealand was a land free of mammals, with the exception of two species of bats and some seals. The Jurassic-like forests were filled with fantastic birds of all shapes and sizes, from giant, ostrich-like moas to green alpine parrots to the iconic, diminutive kiwi. When Australia and New Zealand separated from the mega-continent Gondwana 13 million of years ago, Australia got all the poisonous spiders, snakes and mammals, while New Zealand squeaked by with only birds. But with the arrival of human beings, New Zealand's avian biodiversity took a nosedive -- much like native wildlife has wherever humans have arrived. Early hominids hunted mammoths to extinction, our more recent ancestors drove buffalo to a few protected reserves and we ourselves introduced pests that wiped out the American chestnut. Why would New Zealand be any different?

Europeans understandably needed food when they arrived here, and they populated the wilderness with deer and game birds for hunting and the rivers with trout and salmon for fishing. But they didn't stop there. New Zealand was viewed not as an evolutionary wonder but a blank slate, ready to accept all the comforts of home: songbirds resonant of an English garden, pastoral fields dotted with sheep, the spreading boughs of oak trees to picnic under. Buoyed by such successes, some colonists began to dream even bigger, envisioning a New Zealand filled with kangaroos, zebras and monkeys.

Meanwhile, a war was waged against native species. Farmers shot kea by the thousands, as the highly intelligent birds were harming sheep in much the same way that wolves now badger ranchers in the American west. Other birds of prey were hunted with equal vigor.

Now, less than 150 years later, the attitude has shifted dramatically. Riding a wave of eco-tourism and national pride, native species are now glorified and invasives utterly vilified. Recently, I kayaked with a Kiwi who complained bitterly that deer were eating native plants, without mentioning that the deer are filling an ecological niche left by the moa: clearing the forest underbrush. There is no season on deer; they can be hunted at any time, with whatever means necessary. Weasels are trapped, possums poisoned and roadkill applauded. In 2012, a group of conservationists gathered to create a plan for a predator-free New Zealand. That's the ideal: no more mammals, just the birds, free and wild. Joined, of course, by ourselves. Is it wishful thinking that we can return a land to its original state while continuing to live there?

And the actions of today's environmentalists can be as misguided as those of 19th century colonists. Cyanide and the poison known as 1080 are widely distributed to kill possums and other mammals, but also damage native plants, insects and birds. Driving through the South Island, handmade signs everywhere denounce the use of 1080.

But although human actions have eliminated half of New Zealand's native birds and imposed many new species, there have been a few positive consequences as well. A wallaby introduced to New Zealand may prove to be the species' savior as it becomes more endangered in its native Australia. Similarly, on the other side of the world, a species of fish known as the Sunapee trout has become nearly extinct from the lakes in New England where it evolved, but it continues to thrive in remote alpine lakes in Idaho where it was introduced for sportfishing. Ebb and flow. Give and take. We humans bumble our way through this world, bending it to suit our needs while trying somehow to do what's right. Sometimes we succeed, more often we fail, but rarely are the consequences those we had in mind. 
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