Story: Threatened species
New Zealand’s lizard-like tuatara once lived throughout New Zealand, but became extinct on the mainland after humans arrived. The species survived on some nearshore islands, but people, dogs, cats and rats soon took their toll. Fortunately, people can also do good: raising tuatara in captivity, and removing predators from the islands. The fate of many threatened species lies in our hands.
Full story by Gerard Hutching and Carl Walrond
Main image: Mahoenui giant wētā
The Short Story
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What is a threatened species?
When a species dwindles to very low numbers or lives in just one place in the wild, it is threatened: it may become extinct. Thousands of such species exist worldwide – bears, sharks, snails, corals. ‘Threatened’ ranges from highly endangered to lower risk of extinction.
Why do species become threatened?
It is natural for species to slowly die out. But humans have caused drastic changes in a short time. The main activities that threaten species are:
- destroying habitats (e.g. farming, pollution)
- bringing in weeds and pests
- over-harvesting (e.g. fish, birds).
Human impact in New Zealand
New Zealand’s plants and animals evolved free of many predators. When humans arrived they brought rats and other predators that killed animals and ate plants. Many became extinct or scarce. This continues today.
New Zealand has a high number of threatened species – birds (including kiwi, kākāpō, kea and takahē), marine mammals, bats, frogs, fish and mosses. In 2007 they numbered 2,788, including 37% of the birds and 34% of the plants.
Many smaller species such as worms and insects have not been well studied, and some may have already become extinct.
Conservation projects often focus on birds because they are popular and very visible. For example, in 1976 there were just seven black robins in the Chatham Islands, but now there are about 250.
… and other species
Also being saved and protected are rare species such as:
- tuatara – a lizard-like reptile
- Canterbury mudfish
- red mistletoe.
What is being done?
About 30% of New Zealand is protected conservation land. The government aims to save the diversity of remaining species, and councils are trying to restore habitats. Project Crimson is saving the red-flowered pōhutukawa and rātā. Companies give funding – the Bank of New Zealand is helping to save the kiwi.
How are species being saved?
The Department of Conservation and other groups are saving threatened species through:
- Island sanctuaries. Birds, frogs and other species often survived only on predator-free islands. Other rare animals may be moved there, and trees planted. Native birds are thriving on Kapiti Island, near Wellington.
- Controlling pests. Methods include poisoning, hunting, and building fences.
- Breeding in captivity. For example, takahē eggs are incubated in a safe place, and the chicks are raised, to breed further.