Rising Temperatures Pose a Fresh Threat to Koalas
For years, koalas have been haunted by habitat fragmentation, drought, and diseases such as chlamydia. A newly published study in Biology Letters adds a worrying twist: even a modest increase in ambient temperature can sharply elevate the risk of death for these iconic marsupials.
What the data reveal
Researchers from the University of Sydney examined records of 11,862 koalas rescued between 2000 and 2022 across New South Wales. By linking each admission to the seven‑day maximum temperature recorded at the capture site, they uncovered a clear temperature threshold. When the average seven‑day maximum exceeded 27 °C, adult koalas began to experience a statistically significant rise in mortality. At 30 °C, the odds of death were 1.5 to 3.5 times higher than at a milder 25 °C.
Why heat matters
Koalas possess several physiological and behavioral tricks to beat the heat: they seek shade, cling to cooler tree trunks, and rely on a sluggish metabolism that generates limited internal heat. Their kidneys are also efficient at conserving water. Yet these adaptations are short‑term buffers. Prolonged heat waves quickly dehydrate the animals, force them to travel farther for food or water, and drain precious energy reserves. Sick individuals, particularly those already battling chlamydia, are disproportionately vulnerable during hot spells.
Implications for conservation
Lead author Valentina Mella warns that the northwest region of New South Wales, once dubbed “the koala capital,” now hosts a functionally extinct population. The study equips rescue services with a predictive map of heat‑stress hotspots, enabling faster interventions when temperatures rise above critical levels. Long‑term strategies should focus on expanding canopy cover, establishing watering stations, and preserving cool microhabitats.
Broader relevance
The findings are not limited to koalas. Many mammals share similar thermal limits, meaning that rising heat extremes could ripple through entire ecosystems. Protecting one species often safeguards the broader community.
As climate change pushes average temperatures upward, the phrase “a warm day” will no longer be a minor inconvenience for koalas – it will be a direct survival threat.
Source: https://scientias.nl/de-koala-heeft-een-nieuw-probleem-gewone-warme-dagen/
