Evrim Yazgin
Cosmos science journalist
New research suggests that prescribed burns in South Australia’s Mount Lofty Ranges might be threatening the survival of local reptile species with potential cascading effects for the wider ecosystem.
Such health risks for local wildlife in the region and beyond are likely to become more pronounced as climate change worsens, the authors warn.
The study, published in the Forest Ecology and Management journal, details the findings of a 2-year analysis of the health of 1,750 individuals from 8 different reptile species. The authors investigated how the animals at 18 sites across the ranges responded to fire including prescribed burns – a common fire management practice to reduce bushfire risk.
About 96% of the individuals captured belonged to 3 species: The eastern three-lined skink (Acritoscincus duperreyi), three-toed earless skink (Hemiergis decresiensis) and common garden skink (Lampropholis guichenoti).
The garden skink was the most common of these with 1,310 individuals analysed.
Other species captured during the research included other skinks, eastern brown snake, striated worm-lizard and marbled gecko, but the sample sizes of these other species were too small to be included in the final analysis.
Lead author Shawn Scott, a PhD candidate at the University of South Australia (UniSA), says the garden skink had “significantly poorer body condition immediately following prescribed burns”.
“This suggests that in the short term for the garden skink, fire may be depleting food sources, exposing them to predators, or otherwise stressing these animals in ways we hadn’t fully appreciated,” Scott says.
Animals with injuries such as tail loss, missing digits or scarring had significantly lower body condition in 2 of the species showing that fires compound health problems for the reptiles.
On the flip side, the research suggests that animals living in forests which have not experienced fires for a long period have higher survival rates and are forced to migrate to other habitats less often. Garden skinks, for example, were most often recaptured in forests where there hadn’t been fires for 20 years or more.
South Australia’s Mount Lofty Ranges are a key biodiversity hotspot in the state. The woodlands are dominated by stringybark eucalypts on the mountainsides and golden wattle acacias in the lowlands.
More than 450 native fauna have been recorded in the region, including more than 75% of all the bird species found in South Australia.
There has been an increase in prescribed fire activity in recent years, with 5% of high-risk vegetation areas targeted annually.
“Prescribed burns are often advocated as beneficial for biodiversity,” says Scott. “But our research adds to growing evidence that one-size-fits-all approaches to fire may be harmful to small animals. More nuanced strategies, such as preserving long-unburnt refuges and monitoring fire effects on reptiles, are urgently needed.”
The authors say that the impacts of climate change will increase the importance of researching the effects of fire on small animals and considering new strategies for fire management, especially as fire severity rises.
“We had La Niña, mild conditions,” says co-author and UniSA wildlife ecologist S. “Topa” Petit. “The results could be more dramatic after a drought, for example.”
“Reptiles are critical for healthy ecosystems – they control insect populations and serve as prey for birds and mammals,” says Scott. “If fire regimes are compromising their health or numbers, it could have cascading effects on the whole ecosystem.”
