Acid frogs can stand the heat: amphibian resilience to wildfire in coastal wetlands of eastern Australia

Abstract

Fire has varying effects on species ecology. Knowledge of amphibian responses to fire is particularly limited, with variable responses reported amongst studies. Variability is attributed to differences in fire regimes, sampling methodologies, historical exposure to fire and species traits. Acid frogs, a group of amphibians restricted to acidic coastal heath wetlands of eastern Australia, occupy a discrete ecological niche that is exposed to regular and intense fires. Visual encounter surveys conducted monthly over 2 years revealed different short- and long-term responses to fire in three threatened acid frog species (Litoria olongburensis, Litoria freycineti and Crinia tinnula). Fires altered the thermal properties of habitats by increasing substrate temperature and widening daily temperature ranges. Acid frog populations did not suffer adversely from moderate intensity fires as suitable refuges, including standing water, were available. All species were present shortly after fire with subsequent successful reproduction occurring once wetlands were sufficiently inundated. Time since fire was a strong predictor of landscape scale differences in average relative abundance of acid frogs, yet the relationships varied among species. This highlights the importance of assessing community-wide responses to fire at the landscape scale. The dynamic and adaptive responses observed within acid frog populations demonstrate substantial resilience to fire processes in these fire prone environments.