Island eradications a conservation ‘silver bullet’? – Expert Reaction

New Zealand is leading the world when it comes to preserving islands’ unique and fragile wildlife by eliminating invasive mammals, according to new research.

The international team of researchers, including several New Zealanders, systematically assessed the global impact of eradicating invasive mammals, such as rats, goats and cats, from islands.

Their findings, published today in PNAS, identified more than 230 species on 181 islands that had benefited from eradications. The authors conclude the island pest control is one of the most cost-effective approaches for conservation and note that New Zealand has lead the way.

“Many eradication techniques were first developed in New Zealand, so much so that it’s been commonplace to ‘call the Kiwis’ if you want to eradicate mammals,” said study co-author Holly Jones, an assistant professor in biological sciences at Northern Illinois University. “Now, more and more conservation organizations worldwide are embracing this conservation intervention.”


The Science Media Centre collected the following expert commentary.

Prof Bruce Clarkson, Director of the Environmental Research Institute, University of Waikato, comments:

“This is a compelling evidence based analysis and yes, islands (offshore islands) are a silver bullet for biodiversity conservation. Congratulations to the authors for pulling this together. But they are one silver bullet with others needed. Offshore islands can never save all of New Zealand’s indigenous biodiversity as they are unrepresentative of the full range of ecosystems and habitats of the New Zealand archipelago.

“We need to use all the systematic conservation planning tools at our disposal to determine the balance needed between offshore island restoration/conservation and other types of conservation/restoration eg mainland island restoration including mainland sanctuaries employing predator proof fences and other types of conservation/restoration in a full range of representative ecosystems and habitats to ensure we retain the full range of biodiversity.  So a systematic analysis across the whole system would be needed to demonstrate if more or less offshore island restoration is needed.

“I would also like some more information which characterises the size and habitat diversity of the islands which were the focus of this study and of course from my quick reading of the paper the other components of the ecosystems are not discussed, for example vegetation recovery, plant species and so on.

“Offshore island restoration is also significant as the springboard for the later development of mainland island approaches and the new frontier urban restoration which seeks to reconnect New Zealanders with their biological heritage by reinstating key species in urban environments, for example Zealandia.”

Dr Marie Brown, Senior Policy Analyst, Environmental Defence Society, comments:

“Island sanctuaries provide a critical first line of defence against extinction and have been instrumental in securing small populations of threatened species here and globally. New Zealand has led the charge here and the success of these amazing projects demonstrates both their ecological importance and the unique contribution of NZ science to the rest of the world.

“All of New Zealand’s landmass is an ‘island’ by definition, so this paper illustrates the game-changing impact that a transformative project like Predator Free New Zealand could have. We’d be having very different conversations about conservation in the absence of pests. The challenge here and elsewhere is to work out how to best apply those techniques to populated areas

“It is important to note however, that pest control is the removal of just one pressure. Habitat loss presents an equal or greater threat, and we must do very much better at curtailing that – so that when populations rebound as set out in the article, they have somewhere to live.”