Providing student research grants is a key feature of our Science and Knowledge program, where we assist students in progressing their post-graduate studies and careers.

The program encourages students in the ecological sciences and helps us understand our nature reserves better.

We are delighted to bring you this research report update from 2023 Grand Start Grants – PhD recipient, Jack Bilby.

Comparing the responses of a native and invasive mammal to extreme heat events

• Jack Bilby
• Grand Start Grants – PhD recipient
• PhD, University of New South Wales, UNSW Sydney

Heat waves are becoming more frequent, longer, and more extreme under climate change. The severity of heat waves is predicted to increase the most in arid areas, where native mammals have already undergone the highest extinction rates.
 
Understanding how native and invasive terrrestrial mammals respond to extreme heat events and how effective their responses are will be crucial for future conservation efforts. This research is of significant importance in the context of climate change and wildlife conservation and has the potential to fill a significant knowledge gap and provide hope for the conservation of native species.
 
Jack’s project uses the Greater Bilby (Macrotis lagotis) and European Rabbit (Oryctolagus cuniculus) and the methods thus far have involved attaching GPS units and iButton temperature and humidity loggers to eight Bilbies (3726 total fixes – 200 days) and fifteen Rabbits (6092 total fixes – 295 days) to assess micro- and macro-habitat use during extreme heat events during summer at the Arid Recovery Reserve in northern South Australia.
 

All animals are regularly radio-tracked to assess shelter site selection across a temperature gradient. Accelerometers have also been used on Bilbies (~184 days) and Rabbits (~368 days) to determine energy expenditure and novel neural network analyses to categorise behaviours remotely.
 
While rigorous statistical analyses are yet to occur, the preliminary results are already indicating significant differences in the strategies of Bilbies and Rabbits for avoiding extreme temperatures. During daylight hours, Bilbies consistently experience lower temperatures than Rabbits, while also experiencing far higher humidity

This suggests that Bilbies are deep in their burrows during the heat of the day, whereas Rabbits may remain on the surface or right at the burrow entrance. This observation may suggest that Bilbies rely more on their burrows to avoid extreme temperatures, while Rabbits rely on evaporative cooling to maintain their body temperatures.
 
These findings suggest that Bilbies may be more susceptible to longer heatwaves, where high temperatures penetrate lower into the soil, while Rabbits are more susceptible to heatwaves during drier years. Understanding these differences in susceptibility could be crucial for developing effective conservation strategies for these species in the face of climate change.
 
In addition to more detailed analysis, the next step for this project is to increase the sample size, specifically by collecting data during heat waves to assess how different heat wave attributes (intensity, duration, and frequency) relate to the response variables.
 
Jack is the recipient of another Grand Start Grant – PhD through our 2024 student research grants round to assist him with continuing this multi-year research project. We look forward to bringing you further updates on his research and findings.
 
See details of all our 2024 student research grant recipients here.

Learn more about our Research Grants here.

Donate to and support our Grand Start Grants here.