extreme changes

Extreme and unpredictable environmental changes, such as fires or storms, can pose a serious energetic challenge for endothermic animals, which may cause animals to change their behavioural and physiological responses to increase their chance of survival. In particular, these events can lead to a decrease in food and water resources or a reduction in available foraging time due to detrimental weather or an increase in predation pressure. Such circumstances would lead to a net energy loss as a result of decreased or stressful foraging periods.

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So far, we have examined how small mammals respond physiologically and behaviourally to very low ambient temperatures, heavy rainfall, fires and habitat degradation. We are also interested in examining high ambient temperatures, droughts, storms, strong wind and any other unusual occurrences. Data on how animals cope physiologically and behaviourally with such extreme events are important as the probability of such unusual events is increasing with climate change.

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The graphs below represent changes in physiological (a: torpor frequency, b: torpor bout duration, c: minimum body temperature) and behavioural (d: activity) traits of brown antechinus (Antechinus stuartii) in response to a management burn. The most important thing to note is that all the black bars, representing the animals measured immediately after a fire, are significantly different to all the other bars. In summary, antechinus employed more frequent, longer and deeper bouts of torpor and spent less time active after the fire. This suggests that the animals were stressed and needed to conserve energy, likely due to decreased foraging opportunities as a result of a decrease in food sources and an increase in predation pressure from lack of vegetative cover (as shown in the photos; a: taken shortly after the fire, b: taken one year after the fire).