New Zealand’s native
biodiversity is unique, born of long
isolation as small islands in a vast ocean. The high percentage of
endemic species (those found nowhere else in the world), make New
Zealand’s native biodiversity both special and highly vulnerable.
After splitting from other continents 80 million years ago, evolution
on land took an eccentric course, leading to plants, animals and
ecosystems so distinctive that New Zealand has been described as the
closest scientists will come to studying life on another planet. From
then, until the arrival of humans, it had the longest period of isolation
of any non-polar landmass on earth.
The main reason is that, unlike other continents, New Zealand was almost
mammal-free – the only native mammals were two species of bat, and marine
mammals. For 65 million years, birds dominated the land. Some evolved into
unique new forms – the world’s largest eagle, a flightless nocturnal parrot,
the kiwi with nostrils at the end of its long beak, and the giant moa,
taller than any other bird. Flightless birds and giant insects (such as the
giant weta) filled roles small mammals filled elsewhere – foraging on the
ground, living in burrows and hollows.
Around our shores, nearly 100 native species such as the threatened
bluefinned butterfish live in rockpools, 60 per cent of them found only in
New Zealand and nowhere else.
Mammals began to arrive in numbers about 1000 years ago in the form of
human settlers who bought with them mammal predators such as rats and
possums. Since then, New Zealand’s biodiversity has radically changed on
land, in our rivers, lakes and streams, and in the sea.
https://www.biodiversity.govt.nz/picture/biodiversity/
