I must confess to being rather ignorant about the flora and fauna of New Zealand before arriving here however it didn’t take very long before we began to realise what a unique country this is.
To understand the uniqueness of the country plants and animals you must first know something about its formation. The supercontinent of Gondawana existed over 500 million years ago and it started to separate around 180 million years ago. This break up formed the parts of the world we today know as Australia, Antarctica, Africa, South America, India and New Zealand. New Zealand became isolated around 90 million years ago and it has been out there on its own ever since. As a result it does not have any native land mammals with the exception of a couple of species of bat. Indeed the first humans did not arrive in New Zealand until the thirteenth century with the arrival of explorers from Polynesia.
Approximately 65 million years ago there was a mass extinction event that wiped out 75% of the plants and animal species on earth, including the dinosaurs. The removal of top predators meant that small mammals could evolve rapidly to fill all the newly created empty habitats. The age of the mammals had begun but New Zealands isolation meant that they couldn’t get there. All land mammals in New Zealand today were introduced by humans. In the absence of native mammals the birds flourished. With no natural predators it didn’t matter if the birds could fly or not so gradually, over time, many lost the ability to fly. Much of the bird population was flightless and ground dwelling.
Human settlers in New Zealand began introducing mammals. Cattle, sheep and goats were highly successful and profitable but other introductions were less so. in 1857 1000 Australian possum were brought to the country for their pelts. By the 1980s their numbers were estimated at around 70 million and the environmental effects disastrous. Possums are carriers of TB .They also grazed on native plants which had no adaptations to grazing and they also ate the eggs and chicks of flightless birds which could not escape them. Stoats and ferrets which were. introduced to try and control rabbits also added to the problem. Now birdsong and native birds in the forests are rare. Control measures are now in place to reduce numbers and there has been some success but there is still a long way to go. Native birds are being reintroduced into areas of forest which have been declared predator free.
Isolation has meant that New Zealand has developed a unique native flora. Most native trees are evergreens, species of deciduous trees having been introduced by settlers. There is a relatively high number of species of fern for a temperate climate. As you drive the west coast rainforests you can not fail to be impressed by the number of ferns and their size. Indeed New Zealand national sports teams have the silver fern as their emblem. Mosses an liverworts also abound. Many plants are larger than similar forms elsewhere. Forests are dense with a large under canopy, it is relatively easy to get lost if you stray from a track in such areas. Some of the forests are old and it is easy to see where the inspiration for the Ents in Peter Jacksons Lord of the Rings came from.
