How will Top End geckos cope with climate change?

With the increasing frequency and severity of heatwaves, how will some of our scalier friends cope with looming changes to their habitats? Crocodile researcher Kade Skelton has swapped the prehistoric predators for a littler lizard in order to find out.

Studying a Higher Degree by Research with CDU, Kade Skelton is now focused on a group of native nocturnal lizards found in the Top End, known as dtellas.

“Testing for differences in physiology (the ways in which an animal’s body functions) across species, environments and seasons can indicate whether dtellas are adapted to their local environment or can cope with changes to their environmental conditions.”

The findings may assist with species conservation efforts in the face of climate change. 

Locating lizards

Kade’s research involved travelling to a number of remote locations with different environments across the Northern Territory and Western Australia. 

They wanted to compare the physiological traits of dtellas to their different habitat conditions. 

An animal’s biology only makes sense in the context of its environment.

The dtellas were each placed in an experiment chamber where dry air was passed over their bodies to measure the amount of water the air collected from the dtella’s skin. This allowed Kade to calculate the rate of evaporative water loss.

Some dtellas were also taken back to CDU for another experiment, which involved a large enclosure that was warm at one end and cool at the other. 

“Dtellas were able to select whichever they were most comfortable at, and we measured these temperatures using a thermal imaging camera,” says Kade.

After repeating the experiments in different seasons to measure differences in their hydric and thermal physiology, the geckos were released back to their original habitats.

Will they adapt?

By measuring the rates of water lost passively through the skin and the optimal temperatures at which their bodies function, Kade’s research may hold answers to whether or not they will be able to adapt to environmental conditions changing in the future.

According to the findings, tropical dtellas may be able to cope with the reduced water availability that comes from more arid conditions such as increased drought frequency and severity – a real risk posed by climate change. 

“They can reduce their rates of evaporative water loss by up to 80% during the dry season, surviving up to three weeks without water intake before reaching lethal levels of dehydration,” Kade explains.

While this hydric physiology may serve them well, their thermal physiology is a different story.

As the temperature changes in wet-dry tropics are minimal, they have not needed to be as flexible. 

Because of this, if environmental temperatures change over time as predicted, dtellas are going to be very sensitive to these changes.

“They may be able to adapt behaviourally rather than physiologically by changing the way they use microhabitats; however, this relies on access to favourable conditions in these microhabitats.”

“My findings highlight how the ability to shift physiology in response to environmental changes may be associated with climatic zones, and why it is important to consider this association when assessing species’ risks to climate change.”

Kade hopes the results of their research will also contribute to the importance of considering physiology (and how it relates to environmental differences) in conservation efforts for dtellas. 

CDU is seeking Higher Degree by Research students to take part in research projects just like these. Scholarships are available. Learn more.