Close encounters with tuatara

November 13, 2013
Female tuatara on Stephens Island. Credit: Anna Carter

Anna Carter is conducting a climate modelling study on Stephens Island in Cook Strait, home to New Zealand's largest tuatara population.

Her research examines the delicate gender balance among and how it could be affected by rapid environmental change, such as a 2ºC increase in New Zealand temperatures predicted by 2050.

A key factor in how tuatara will cope lies in recent Victoria-led research which has revealed that the sex of baby tuatara is determined solely by the surrounding eggs during incubation.

"Rapid climate warming could disrupt this system, in which warmer incubation temperatures above 21.7 ºC leads to the development of males only. My aim is to predict the potential for changes in nest temperatures, using mechanistic modelling to investigate the physical processes underlying soil temperatures.

"Accurately predicting soil temperature is more complicated than collecting field measurements, especially if produces new situations we haven't measured before.

"Particularly on Stephens Island, which is returning to a pre-human, forested state, we need high resolution models of soil temperatures in tuatara nests as well as a thorough understanding of their nesting behaviour, such as their choice of habitat and nest depth."

Anna's behavioural analysis of nesting female tuatara has included several month-long trips to Stephens Island, tracking the reptiles during their nocturnal nesting period in November. She has also made numerous visits to Little Barrier Island to study the small population there.

"The findings from Stephens Island will help predict how smaller, more vulnerable populations of tuatara might fare in future.

"The practical aim of my research is to provide information relevant for conservation of tuatara and other species with temperature-dependent sex determination."

Anna's research expands on work by her co-supervisor, reptile expert Dr Nicky Nelson, who heads Victoria's Conservation Biology programme, and Dr Nicola Mitchell, a former Post-Doctoral Fellow at Victoria currently based at the University of Western Australia. This research developed initial predictive models for temperatures and hatchling sex ratios of tuatara on North Brother Island in Cook Strait, New Zealand.

Explore further: Tuatara, the fastest evolving animal

Related Stories

Tuatara, the fastest evolving animal

March 20, 2008

In a study of New Zealand’s “living dinosaur” the tuatara, evolutionary biologist, and ancient DNA expert, Professor David Lambert and his team from the Allan Wilson Centre for Molecular Ecology and Evolution recovered ...

Rare reptile hatchling found on NZ mainland

March 19, 2009

(AP) -- A hatchling of a rare reptile with lineage dating back to the dinosaur age has been found in the wild on the New Zealand mainland for the first time in about 200 years, a wildlife official said Thursday.

Help at hand to relocate threatened species

October 17, 2013

Australian and New Zealand scientists Thursday said they have devised the "first rigorous framework" on deciding whether to relocate endangered animals threatened with extinction by climate change.

Warmer beaches influence sex ratios of loggerhead hatchlings

October 22, 2013

While Dirk Hartog Island is the southernmost rookery for loggerhead turtles (Caretta caretta), UWA and Murdoch University biologists say climate change may ultimately lead to the species nesting successfully on beaches further ...

Recommended for you

In changing oceans, cephalopods are booming

May 23, 2016

Humans have changed the world's oceans in ways that have been devastating to many marine species. But, according to new evidence, it appears that the change has so far been good for cephalopods, the group including octopuses, ...

A 100-million-year partnership on the brink of extinction

May 24, 2016

A relationship that has lasted for 100 million years is at serious risk of ending, due to the effects of environmental and climate change. A species of spiny crayfish native to Australia and the tiny flatworms that depend ...

Rare evolutionary event detected in the lab

May 23, 2016

It took nearly a half trillion tries before researchers at The University of Texas at Austin witnessed a rare event and perhaps solved an evolutionary puzzle about how introns, non-coding sequences of DNA located within genes, ...

Is aging inevitable? Not necessarily for sea urchins

May 25, 2016

Sea urchins are remarkable organisms. They can quickly regrow damaged spines and feet. Some species also live to extraordinary old ages and—even more remarkably—do so with no signs of poor health, such as a decline in ...

Why fruit fly sperm are giant

May 25, 2016

In the animal kingdom, sperm usually are considerably smaller than eggs, which means that males can produce far more of them. Large numbers of tiny sperm can increase the probability of successful fertilization, especially ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.