New Caledonia: plant paradise of the Pacific

The Pacific Ocean might be mostly water, but over twenty-seven thousand islands are dotted across its shimmering surface. On each speck of sand and stone, life has found a way to survive, adapt, and diversify; what little land there is in this sprawling sea supports a vast array of unique species. But one island nation stands head and shoulders above the rest – known for both its coral and its conifers, welcome to New Caledonia!

An aerial view over Noumea, the nation’s capital.
Image from brewbooks, via Flickr

It ain’t easy being green – unless you live here

New Caledonia could be the poster child for cultural diversity; the native Kanak people have mingled with French colonisers and waves of Asian and Polynesian immigrants to create a melting pot with truly international flavour. Scientists, however, are far more interested in the diversity of New Caledonia’s leafy residents.

Many of the Pacific’s plant species are found on hundreds of different islands – and sometimes as far afield as Asia and Australia. New Caledonia, on the other hand, simply won’t be outdone when it comes to individuality. An astounding four in five of New Caledonia’s more than three thousand plant species are endemic – found nowhere else on Earth. From the world’s most ancient flowering plant to its only parasitic pine tree, New Caledonia is filled to the brim with botanical sensations. How did all this richness come to be? The answer’s buried in the soil, and across the sea.

 

Amborella is only found in New Caledonia’s rainforests. It’s also the sole member of the world’s oldest flowering plant family! Image from scottzona, via Flickr

Bon voyage, baby

Head out for a bushwalk on this island paradise, and there’s a good chance you’ll be reminded of an Australian nursery. Some of our most iconic plants, like grevilleas and bunya pines, crop up all over this far-flung nation. But these aren’t imports – they travelled across the ocean with the island itself!

Most of the islands in the Pacific formed from volcanic eruptions, mere babies in geological time. New Caledonia is much, much older: it was born from an ancient landmass called Gondwana, which once joined the southern continents together. The breakup of Gondwana began almost 200 million years ago (mya), but around the same time as the dinosaurs died out (65 mya), New Caledonia broke away from eastern Australia, and drifted north.

Alone in the big blue, this enduring isolation has given the plants of ancient Australia time to evolve into a range of new species. The stable, moist climate of the tropics also helped these old groups to flourish (particularly in the mountain rainforests), while they died out in Australia as deserts gradually replaced the lush woods of old. To botanists, New Caledonia’s flora is a whisper of what once grew upon our red dust.

 

New Caledonia has 14 species of Araucaria pine – an ancient Gondwanan group also found in Australia. Image from dcaloren, via Flickr

 

If I had a nickel for every time…

Visit the southern hills of New Caledonia, and you might be reminded of this same red dust – but the local dirt isn’t from Uluru. Geologists think this colourful soil formed well after New Caledonia split from Australia, when a portion of the Earth’s mantle poked above the crust. This rumble from below left behind a rare, strange rock known as serpentine. The soils that form from serpentine are equally bizarre: rich in toxic metals, and lacking the nutrients that plants need to grow. Of the many toxic metals, nickel is especially abundant – New Caledonia holds a whopping one-tenth of the world’s reserves.

Nickel deposits are great news for mining companies, but pure poison for most plants. Some of New Caledonia’s plants have bucked the trend and adapted to this lethal toxin, moving onto the free real estate of these serpentine wastelands. The untapped potential of this new environment led to another explosion of diversification, as nickel-loving plant species gradually spread and competed to fill gaps in the landscape. Today, the result is an alien shrubland that coats the rolling slopes and valleys of the south – only 9% of the species here can be found elsewhere in New Caledonia, let alone the world.

 

The serpentine soils of southern New Caledonia look like they could be straight from Mars.
Image from dcaloren, via Flickr

 

A defoliated future?

It should be clear by now that this humble archipelago has been blessed with nature’s bounty. But will this bounty last forever?

The local fossil record shows that, like most of the Pacific’s islands, big extinctions followed human arrival. Islands are naturally susceptible to human disturbance, and this French outpost is no exception. Giant turtles, snail-munching land crocs (really!), and a bevy of hapless birds have all vanished from New Caledonia since the Kanaks first landed on its pristine beaches.

The story for plants is less clear – they don’t have bones! – but we do know that land use across the nation is putting on the squeeze. A horrifying ninety-eight percent of western New Caledonia’s dry forests have already been wiped out for mining and development. Will New Caledonia still be an arborescent ark in the centuries to come? That depends on us.


13 Responses to “New Caledonia: plant paradise of the Pacific”

  1. Heidi Roleff says:

    Fascinating read. Biodiversity is so important, it’s such a shame to be facing loss like this. What an interesting history.

  2. Oakley Germech says:

    Thank you! It’d be really interesting to see how similar the soils of Mars and New Caledonia are 🙂

  3. Oakley Germech says:

    Glad you liked it, Lindy 🙂

  4. Oakley Germech says:

    Thank you so much for the kind words, Kaya!

  5. Kaya B Moore says:

    Wow Oakley, This was a truly beautiful piece of writing to read. Your vocabulary is exquisite, which paralleled the diversity of the plants you were describing.
    Can’t wait to read your others!

  6. Jillian Cornelious says:

    Oakley, this is a fabulous read! Those serpentine soils could provide a handy model for astrobiologists who will be trying to grow plants on Mars. My favourite line from your blog: ‘New Caledonia’s flora is a whisper of what once grew upon our red dust’. Love it, well done!

  7. Lindy says:

    Thanks, Oakley. That was really interesting.!

  8. Oakley Germech says:

    Thanks, Bruce! Glad you enjoyed it 🙂

  9. Oakley Germech says:

    Thank you so much for your feedback 🙂 Flights are $545 return at the moment – go before all the trees are cut down!

  10. Oakley Germech says:

    Thanks so much, Kim! I agree – it’s so upsetting to read all the facts and figures and see just how extensive the problem is. And plants are so important for habitat structure that affects ALL life in the environment; it’s almost more scary to me to see photos of land clearance than when I see photos of dead animals.

  11. R. Bruce Richardson says:

    This is wonderfully written… love your style. It was honestly a fun read. Well done, Oakley! Well done!

  12. rwills1 says:

    I’ve always wanted to go to New Caledonia, and this blog post just makes me want to go there even more. I especially like the use of bold text to highlight the important bits, and might even steal that technique for my own use in the future.

  13. Kimberly Chhen says:

    Beautifully written piece. It’s devastating the impacts we as humans have on our environment. On top of that, we tend to associate extinctions with animals rather than plants. Your blog really put it into perspective.