Maria Island, conservation history on Auckland’s doorstep

Aotearoa is now a world leader in conservation and particularly protecting islands from the ravages of invasive species, but did you know that it is in the Hauraki Gulf where the dream of a predator free New Zealand first began?

By Matt Rayner Senior Research Fellow, Land Vertebrates 

The Hauraki Gulf is studded with over 50 islands from grand barrier isles such as Aotea to small rocky islets, swept by salt spray. These islands are like sparkling jewels in the gulf’s conservation crown; many being havens for native biodiversity, either freed from invading pests through eradications, or never having suffered invasions by our worst mammal pests including browsers such as possums, or predators such as cats, rats, mice, stoats, and dogs.

Not far from our biggest city, about 20 km to the Northeast, lies a little island called Maria/Ruapuke. A former WWII bombing practice target, roughly 150 metres long by 100 metres wide it doesn’t look like much, but it’s here that the dream of a predator free New Zealand began.

In 1960, Ruapuke/Maria Island was successfully cleared of rats that had been decimating the population of takahikare/white-faced storm petrels that breed there. In 1964, the island and the nearby David Rocks were declared the first islands in the world to have rodents eradicated from them, a new idea for conservation science. The approach to rat eradication became a model for other predator eradication programs globally.

Today Maria is honeycombed with seabird burrows, with five seabird species including the oi/grey-faced petrel, kuaka/northern diving petrel, pakaha/fluttering shearwater, korora/little blue penguin, and takahikare/white-faced storm petrels calling the island home. These seabirds leave behind a top dressing of poo (guano), full of essential nutrients which help fire up the island’s food web. Plants thrive in the rich soil feeding invertebrates, reptiles, and the land birds. Run-off of nutrients into the surrounding sea feeds the undersea seaweed forests benefiting all near-shore marine life, which (if protected) contributes to flourishing marine ecosystems.

Along with scientists from the Auckland Council we have been visiting Maria to count the size of the white-faced storm petrel population that was so impacted by rats sixty years ago. Our work is part of a wider project seeking increased marine protection in the Hauraki Gulf with a focus on the interconnection between land and sea. Through seabirds, islands like Maria are fundamentally linked to their surrounding waters, meaning it makes no sense to protecting the land without protecting the sea.