Six new species of wētā discovered in New Zealand, as their habitat slowly disappears | New Zealand


Six new alpine species of New Zealand’s most unusual and beloved insect – the wētā – have been discovered, but it’s a bittersweet victory, with further research outlining the threat global warming poses to their snowy mountain habitat.

Wētā belong to the same group of insects as crickets and grasshoppers, and there are between 70 and 100 species of wētā endemic to New Zealand. They are wingless and nocturnal, and some, including the wētāpunga, are among the heaviest insects in the world – comparable to the weight of a sparrow.

Forests, grasslands, caves, and alpine terrain once teemed with wētā, but their populations have suffered from the introduction of foreign pests and increasing habitat decline due to dairy farming. Sixteen of New Zealand’s wētā species are endangered, and the remainder are listed as threatened or endangered.

Today, global warming is accelerating their decline, especially for the elusive alpine wētā who live in the mountains – a land that is gradually disappearing and becoming isolated.

“We knew there were wētā up there at high altitude, but the description of their variation was never made, because even though we knew they were there, they weren’t getting many sightings” said Steve Trewick of Massey University. ecologist and wētā specialist.

Alpine wētā are agile (one is nicknamed the Mount Cook flea, despite its much larger size) and have an impressive ability to freeze solidly through the harsh winter months before thawing again in the spring.

But in the excitement of the “fantastic” discovery comes a grim realization: “Now we know they’re there and we can sit and watch them disappear,” Trewick said. “We are still discovering what we have, and at the same time we are discovering this, we know that biodiversity is more threatened than ever,” he said, adding that alpine habitats topped the list of destruction.

The latest report from the Intergovernmental Panel on Climate Change (IPCC) has found that it is now ‘almost inevitable’ for temperatures to exceed 1.5°C – the level above which many of the effects of the climate degradation will become irreversible.

A paper Trewick helped write, published in the Royal Society, examines climate change and alpine insects, including the wētā’s cousin, the grasshopper. It shows that global warming seriously threatens the alpine environment, which will have devastating consequences for biodiversity.

“As the planet warms, the alpine zone is rising in the mountains, so the cold conditions become more and more attenuated for the mountain tops – and the mountains have a finite height.”

When these alpine environments shrink, they become isolated from other similar terrain, creating small isolated populations of animals, which then become more prone to extinction.

While the research focuses on New Zealand’s biodiversity and terrain, Trewick said it has wider applications and demonstrated that “no part of the planet is immune to global climate change”.

“All of these taxa associated with these habitats are going to increasingly feel the pinch over the next 30 to 50 years – we’re talking over human lifetimes.”


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