The
biodiversity of
New Zealand, a large
island nation located in the southwestern
Pacific Ocean, is one of the most varied and unique on earth due to its long isolation from other
continental landmasses. Its affinities are derived from
Gondwana, from which it
separated 84 million years (
Ma) ago,
New Caledonia and
Lord Howe Island, both of which are part of the same continental
plate as New Zealand, and
Australia. More recently a component has been introduced by humans. New Zealand's pre-human biodiversity exhibited high levels of
endemism, both in its
flora and
fauna. Prior to 66 Ma ago, the fauna included
dinosaurs,
pterosaurs and marine reptiles such as
mosasaurs,
elasmosaurs and
plesiosaurs. The range of ancient fauna is not well known, but at least one species of terrestrial
mammal existed in New Zealand around 19 Ma ago. For at least several Ma before the arrival of the human and its
commensal species, the islands had no terrestrial mammals except for
bats and
seals, the main component of the terrestrial fauna being insects and birds. Its flora is dominated by Gondwanan plants, comprising historically of forests, most famously the giant kauri (
Agathis australis). New Zealand has developed a national
Biodiversity Action Plan to address conservation of considerable numbers of threatened flora and fauna within New Zealand.