Unique Aotearoa

Okies, so here we go - this could be an epic.

I've been in NZ now for the best part of 2 years, and the more I learn the more I fall in love with the place. It's unique in so many of its species, both flora and fauna, and that has now become part of my work.

I am now part of the education education team at Zealandia:The Karori Sanctuary Experience. Our job is to interpret Te Māra a Tāne (The Forest of Tāne), why Aotearoa/New Zealand's flora & fauna are so unique, and a whole host of learning outcomes.

I've just sat down to start reading George Gibbs' "Ghosts of Gondwana" - recommended reading for nearly all environmental/ecology course in NZ, and for us newbie guides. He sets out to explain species past and present, how they evolved, and why - biogeography.

I'm hoping to pop a few nuggests of info into this blog to give y'all an appreciation of why this land is so hauntingly incredible, and make you want to visit Aotearoa to see some of the weird and wonderful creatures we have here.

Here goes....

To understand New Zealand's flora and fauna, you have to go back in deep geological time, to around 80mya when it first became isolated from the super-continent Gondwana, and began to drift away - as a continent known as Zealandia - into what is now known as the Pacific Ocean & Tasman Sea. Isolation creates an 'island effect' whereby evolution takes its own merry course free from factors which are present in other mainland areas

Zealandia is a mostly submerged continent now, but maps show the size of the continent which New Zealand & New Caledonia are only the 'tip of the iceberg' of.

There is not only one or two factors which have shaped Aotearoa's flora and fauna; Gibbs gives seven factors in the uniqueness of New Zealand's flora and fauna:

• Gondwanan Heritage
• Lack of Mammals
  
• Dispersal & Invasion
• Orogeny (mountain building)

• Pleistocene Glaciation
• The Oliogocene Drowning
• Human Intervention
  

Gondwana Heritage
The "Moa's Ark" theory that many of New Zealand's species were extant on the landmass as it broke from Gondwana is now largely disproved with leaps forward in understanding in the dynamic geology of the landmass over time (see Oligocene drowning), however there are some species, such as the Tuatara, which are almost certainly surviving ancestors of Gondwana species which simply floated away with Zealandia when it split (this is known as Vicariance) and have evolved over time in isolation. The Tuatara for example is largely unchanged in about 200 million years, and has no living relatives in any of the Gondwanan countries, despite fossil evidence to show they were fairly widespread before mammals; thus we are able to summarise their presence in NZ is due to Gondwanan heritage. Likewise NZ's frogs are all endemic and thought to be of Gondwanan origin.

Mammal Free?
In New Zealand a major factor in the story is the lack of mammals. Bats aside, there were no mammals in New Zealand up until recent times when humans arrived ~ and that evoluntionary gap has been a massive factor in how NZ's species developed. Mammals hunt with their nose, Birds with their eyes and ears. In a land dominated by birds, Aotearoa's flora and fauna evolved to evade/disuade their predators; for example the Kakapo became noctournal and camouflaged - completely at odds with other parrot species around the world. As the Falcon swoops from its perch, the forest goes silent. We startle a Tuatara and it will most likely retreat into its burrow. All of these behaviours do not work with mammals, as they aren't looking for their prey, so much as sniffing it out.

Dispersal and Invasion
It is scientifically proven that not all of NZ's biota were extant when it broke away from Gondwana, thus we accept certain species of flora & fauna were dispersed here from elsewhere - most commonly Eastern Australia. Some come by sea, some by wind - even as recently as 100 years ago magpies were 'blown over' from Australia in a storm. The bulk of New Zealand's flora and fauna are here by dispersal it is currently thought; our short tailed bats (pekapeka) for example, were seemingly dispersed here from Australia around 20 mya, but subsequently died out in Australia. A common plant - the hebe genus - almost certainly dispersed here, and since its introduction 10 mya has undergone massive speciation (i.e. the number of species has increased and spread to new habitats) and then dispersed on to Chile, Australia and New Guinea. Perhaps the most famous of our species - Kiwi and Moa - both were imports, and whilst they have common distant ancestors, they colonised New Zealand on different occasions and in different time periods.

Orogeny
Not as rude as it sounds, simply it refers to mountain building. New Zealand's mountains are young - less than 5 million years old. The alpine region of Aotearoa holds over 30% of our native flora species and probably the same of the invertebrates. Good examples to start with - the ony alpine parrot in the world - the Kea, the only alpine gecko in the world - black-eyed gecko, and the only alpine cicadas in the world - black mountain cicadas. Their story? Well, when the plate boundary became active again, saving NZ from certain drowning, the mountains began to build - rapidly creating a whole new tree-less environment for both in situ species and new imports to colonise.

The Oligocene Drowning
It's now thought by geologists that Aotearoa almost sank completely - some even believe it did - due to a think crust which wasn't buoyant enough to stay afloat. Gibbs suggests that New Zealand around 23 mya was simply a chain of islands, the largest about the size of New Caledonia today. Less land - less habitat for biodiversity is the thought, and it was in this stage that a lot of extinctions could have occurred. However not everything got wiped out it seems - fossilised pollen samples show continuation of certain types of flora, and the continuation of species such as the Tuatara, Moa, Kiwi & endemic Frog species suggest they were able to survive on this island chains.

Pleistocene Glaciation

With an ice age enveloping the Northern hemisphere around 100'000 years ago, so too came cooler climes in New Zealand. The Southern Alps, a product of orogeny mentioned previously, were the first place to feel the pinch. Snow turned to ice as the temperatures dropped, and slowly giant rivers of ice grew into the valleys and spilled out to sea - New Zealand's glaciers formed. Flora & Fauna species would have been forced to adapt, or would have perished in this cold climate, but many of NZ's species show cold-tolerancy quite unnnecessary in today's climate, some such as the Tuatara are known to hibernate/lay dormant for long periods in their burrows for example.

As the global climate began to warm again about 90'000 years later (that's a long hibernation) or 10'000 years ago roughly, the Aotearoa's ice covered lands began to melt. The process of glaciers advancing and retreating shaped New Zealand's landscapes that we see today - Fiordland's Malborough Sounds, river valleys of the West Coast, the Canterbury Plains' braided rivers etc. The uncovering of the land would've given rise to gradual reforestation, and new habitat for many of Aotearoa's flora & fauna.

Human Intervention
And then the humans came to the party. It started with a wave of Polynesians arriving and settling the island - until this point there is no evidence of any human settlement, meaning flora & fauna had evolved without human interference. The Polynesians, who settled and became the Māori people of Aotearoa, brought with them dogs and kiore (Polynesian Rats), they hunted and fished, and altered the land for settlement, fortifications & farming - causing loss of forest cover, species loss (many species became extinct), and an alteration in behaviour of species, especially birds.

With the second wave of settlement - Pakeha / Europeans - much more widespread changes came about, much faster. Land was cleared in huge percentages, but worst of all the introduction of mammals and environmental weed-species were brought over in abundance.

As we now know, many of these mammals - especially mustelids, possums, rats, cats & dogs, have been & are still responsible for the carnage which has beset the New Zealand native flora & fauna.

So what next?
Our aim as guides is to not only entertain and inform our guests (be they 8 or 80), but to tie our stories, props and explanations back into these topics; if we can do this, we can make our visitors appreciate why Aotearoa's species are so interesting and different, and why we must try to save them from a new wave of extinctions which threaten.

I see Zealandia as a great leap forward in this conservation thinking - it is human intervention which is too-rapidly changing the face of the planet, and humans who can make the changes to prevent annihilation of some of the precious, interesting, important endemic species of New Zealand (and throughout the world).

A large part of New Zealand's species-focused conservation is done on off-shore islands, but Zealandia is a 'mainland island' on the edge of Wellington, with the potential for tens of thousands of Kiwis and tourists to visit. With the environmental education we can provide, and the revenue generated from tourism, there is the potential for successful conservation of these species on the mainland.

I appreciate the vision that our trustees have - mainland islands such as this spreading throughout Aotearoa and the rest of the world, linking up patches and corridors for the re-generation and conservation of fragmented ecosystems. Conservation has to be a balance now; looking after the ecosystems which support life, be it biodiversity as a whole, or simply our own, and space and resources for ongoing human inhabitation.


Make sure you also check out The Unnatural History of the Kakapo:

The Unnatural History of the Kakapo Opening Sequence from Scott Mouat on Vimeo.

The world's last remaining kakapo population is plagued by a deadly curse, without a cure it will be the end of the worlds rarest and strangest wild parrot.