Media release
From: Flinders UniversityClimate change and habitat loss are affecting animal populations around the world and reptiles such as South Australia’s own endangered pygmy bluetongue are susceptible to higher temperatures and declining long-term rainfall trends.
Flinders University scientists are working on securing a sustainable future for the burrow-dwelling endemic skink (Tiliqua adelaidensis) by assessing their suitability to cooler and slightly greener locations, below their usual range in the state’s drier, hotter northern regions.
While the lizards take time to acclimatise to their new homes, translocation remains one of the more important ways to conserve rare species and mitigate extinction risk to climate and habitat changes.
The latest research, outlined in a new article in Biology, compared the ability of three separate pygmy bluetongue lizard populations to withstand different microclimates in South Australia – between the northern Flinders Ranges near Jamestown, Mid North near Burra, and southern-most translocation sites near Tarlee and Kapunda.
The study, led by PhD candidate Deanne Trewartha from the College of Science and Engineering, says moving wildlife adapted to a hotter, drier location to another microclimate can mean exposure to different temperatures, water availability and humidity and needs extensive assessment.
“We need to understand how this species, which are highly dependent on body temperature, adapt to cooler and often wetter seasons in these new environments,” says Ms Trewartha, from the Flinders University Lab of Evolutionary Genetics and Sociality (LEGS) research group.
Reptiles rely on attaining certain body temperatures for basic bodily function and increasing body temperature raises dehydration risk.
She says the research so far suggests acclimatisation to new sites may take longer than two years for all three populations and may vary with latitude of origin.
“Despite this acclimatisation delay, our results indicate that these lizards may cope with translocation as a mitigation strategy in the longer term.
“Further monitoring of the three lineages will continue to see any behavioural variations in wet versus dry seasons and the long-term behavioural acclimatisation periods for translocations.”
Australia has the highest reptile diversity in the world, and Flinders University Professor of Biodiversity and Ecology Mike Gardner says translocation may be the only way for the conservation of numerous small burrow-dwelling reptiles, other ectotherms and reptile species in future.
“With high biodiversity loss, translocation to ‘future-suitable’ sites is becoming increasingly urgent for the conservation of numerous reptile species,” says Professor Gardner, who leads an Australian Research Council Linkage project to study various pygmy bluetongue groups at different latitudes in South Australia.
“So far, these three populations are showing various responses to their new locations, but behavioural variations may not be detrimental in the long term and may potentially aid animals in acclimatising to changed environments to optimise their chance their survival.”
A previous study published last year noted differences between the way the colonies behaved.
From spring 2020 to autumn 2021, monthly monitoring of behaviours found the translocated southern lineage lizards showed significantly less daily activity and were active at lower temperatures and higher humidity than northern lineage lizards.
Southern lineage lizards allowed a human observer to approach closer as base-of-burrow humidity increased, while northern lineage lizards were quicker to retreat into burrows, at both source and translocation sites.
The article, ‘Lizards, lineage and latitude: Behavioural responses to microclimate vary latitudinally and show limited acclimatisation to a common environment after two years’ (2025) by Deanne M Trewartha, Stephanie S Godfrey (University of Otago) and Michael G Gardner has been published in Biology DOI: 10.3390/biology14060622.
https://doi.org/10.3390/biology14060622
This project was carried out in accordance with Flinders University ethics approval E453-17, Department of Environment and Water ‘Take from the wild’ permit 20210331 and research permit G25011.
Acknowledgements: The authors acknowledge the Ngadjuri people, who are the traditional custodians of the Mid North study sites and represent the oldest human culture. We acknowledge their elders, past, present and emerging, and that sovereignty was never ceded. Thanks to the Nature Foundation, relevant private landowners, Department for Environment and Water, Renewable Energy Systems Pty Ltd, Flow Power, Nature Foundation and Adelaide Airport Limited for their support in accommodating this research. Thanks to Mark Hutchinson for advice on the species and project methods, and to David Mansueto for assistance with date/time matching and import code.
