Show all
Browse by Editions Authors Topics Locations

1200 kilometres to track lizards

menu_book picture_as_pdf bookSophie Cross Environment Australia Western Australia
Issue_40_April_2020-52

1200 Kilometres to Track Lizards

Sophie Cross

The method used GPS and a VHF tracking antenna to follow the perentie. All pictures by Sophie Cross

In 2017 and 2018 I walked the equivalent of 28 marathons in the scorching Western Australian outback. Why, you ask? To assess how some of Australia’s largest lizard species interact with restored mines.

52 | BWA April 2020


Sophie Cross walked more than 1200 kilometres and tracked a young adult perentie to find out whether they were using a restored mining area.

BWA April 2020 | 53


Do animals return to restored habitats?I wanted to know whether restored habitats properly support the return of animals, or whether animals are only using these areas opportunistically or, worse still, avoiding them completely.

To study how reptiles behave in restored mining areas, I hand-caught and tracked a young adult perentie. The perentie is Australia’s largest lizard species, growing to around 2.5 metres in length, and is an apex predator in arid parts of the country.

I tracked the lizard for three weeks to determine whether it was using the restored area, before the tracker fell off during mating.

Previous methods of tracking assume the animal used all locations equally. But I used a new method that measures both the frequency with which animals visit particular places, and the amount of time they spend there. This provided a valuable opportunity to assess how effective restoration efforts have been in getting animals to return.

Restoration needs more workMy research, published in the Australian Journal of Zoology, shows that while the perentie did visit the restored mine, it was very selective about which areas it visited, and avoided some places entirely. The lizard went on short foraging trips in the restored mine area, but regularly returned to refuge areas such as hollow logs.

This is because hot, open landscapes with minimal refuges present high risks for reptiles, which rely on an abundance of coverage to regulate their body temperature

and to avoid predators. Such costs may make these areas unfavourable to reptiles and limit their return to restored landscapes.

In comparison, undisturbed vegetation supported longer foraging trips and slower movement, without the need to return to a refuge area. Unfortunately, areas undergoing restoration often require exceptionally long time-periods for vegetation to resemble the pre-disturbed landscape.

How can we help reptiles move back into restored areas?Restored landscapes often lack key resources necessary for the survival of reptiles. As vegetation can require a long time to reestablish, returning fauna refuges like hollow logs and fauna refuge piles (composed of mounds of sand, logs, and branches) could be crucial to aiding in the return of animal populations.

My research team and I have called for animals to be considered to a greater extent in assessments of restoration success. In the face of increasing rates of habitat destruction, we need to understand how animals respond to habitat change and restoration.

Failing to do so risks leaving a legacy of unsustainable ecosystems and a lack of biodiversity.

Sophie CrossPhD candidate, Curtin University

This article first appeared in The Conversation on 7 February 2020.

The tracking device revealed how the perentie navigated a restored mine, before it fell off during mating.

54 | BWA April 2020