New Zealand's remarkable Maud Island frog

In time to celebrate international Save the Frogs Day, a major study has shown that one of New Zealand’s frog species not only lives longer than most other frogs, but has one of the smallest home-ranges known for any vertebrate.

Maud Island, in the Marlborough Sounds, is home to a small and globally threatened frog—Leiopelma pakeka. The frogs grow to just 5cm in length.

Maud Island frogs have been studied by Victoria University Associate Professor Ben Bell for 35 years, making his study one of the longest studies of frogs to date in the world—and it is still ongoing.

The data have shown that the frogs have some interesting oddities: they live for 35 to 40 years—extreme longevity for wild frogs—and have one of the smallest home-ranges known for any vertebrate.

Dr Bell says that the results are remarkable. "The frogs exist within 30 square metres for their entire lives, shifting the centre of their range by only 1.3 metres every ten years. This extreme site fidelity is unusual for frogs.

"This research has given us a much better understanding of the life-history patterns of these native frogs. It assists their conservation management by providing long-term data on their numbers, growth rates, movements and survival. It also contributes directly to the global Save The Frogs campaign, by providing basic population data on a frog of very limited world distribution," says Dr Bell.

For many years the long-term native frog research undertaken by Dr Bell has provided the Department of Conservation with up to date population data for assessment of the status of the Maud Island frog, as well as Archey’s frog which he also studies in the Coromandel Ranges.

This year’s international Save the Frogs Day takes place on Saturday, 28 April.

Dr Bell is an Associate Professor within Victoria University’s Centre for Biodiversity and Restoration Ecology, a centre that identifies and researches the restoration of depleted populations, species and communities in ecosystems that have been impacted by human activity. Dr Jennifer Moore of Michigan State University, who completed a PhD at Victoria in 2008, analysed the results in collaboration with Dr Bell.