New Zealand’s unremitting war against pests has earned it the global top spot for island pest eradication but researchers warn the pace of eradication is slowing.
An international study, published in Scientific Reports, found New Zealand leads the world in creating island sanctuaries and is responsible for nearly a quarter of the world’s island pest eradications. Australia is the second most successful with just over 12% of global eradications.
“The reason New Zealand can lead the world is because we support [pest eradication] at all levels, from the grassroots to the government,” said Prof James Russell, a New Zealand co-author on the study from the University of Auckland.
The country has a well-established history of driving out pests from islands. The fruits of those efforts have been many – from thriving native bird populations, to creating eco-tourism destinations that further generate community interest in protecting species.
It has also committed to an ambitious national programme – Predator Free 2050 – that aims to clear stoats, rats and possums from 26m hectares (64m acres) of mainland, along with all offshore islands, by 2050.
Islands are hotspots for biodiversity and extinction, representing just 5% of Earth’s land area but enduring 61% of extinctions since the 1500s and hosting 40% of today’s highly threatened vertebrates.
The review of 1,550 eradications on nearly 1,000 islands since 1872 found an 88% success rate using methods such as hunting, trapping and targeted poisoning to help restore island biodiversity. Completely removing invasive species from islands has proven to be one of the most effective tools at halting and reversing this damage, the study found.
Last month, New Zealand conservationists announced they would attempt the biggest ever eradication of invasive species on an inhabited island. The project aims to remove predators including possums, rats, feral cats and hedgehogs from Rakiura/Stewart Island – the country’s third largest Island – over the next four years.
But Russell said it was heartening that efforts were also being helped by people setting traps in their own backyards. “Now the database shows that everyone doing things in their backyard makes a huge difference internationally,” he said.
The country’s conservation technology and expertise has become something of an export industry for New Zealand, Russell said, and that was something to be proud of. “We don’t make a lot of money exporting it, but we do make the world a better place.”
The research may have given New Zealand’s pest control efforts a gold star, but it also showed that its eradication efforts were slowing down. This is partly due to conservationists making headway on the smaller islands and leaving the islands with a larger land mass til last – meaning control efforts take longer to produce results.
But that does not mean the country can become complacent, Russell said.
“It’s not enough to just let nature be tucked away in some corner and feel good that we’ve created a few islands. We should be very proud of that … but we should have [native birds such as] saddlebacks, kākāpō and kōkako everywhere in New Zealand.
“It seems manifestly unjust to me that they can’t be.”
