Wildlife in the line of fire: evaluating the stress physiology of a critically endangered Australian marsupial after bushfire

Australian native fauna are thought to be well adapted to fire-prone landscapes, but bushfires may still pose considerable challenges or stressors to wildlife. We investigated the impact of bushfire on the stress physiology of the woylie (brush-tailed bettong, Bettongia penicillata) a critically endangered Australian marsupial, and assessed whether fitness indices (body condition and parasite load) influenced stress physiology before and after the fire. We hypothesised that there would be a significant change in stress physiology indicators (in the form of faecal cortisol metabolites, FCM) following the fire, compared with the months previous. We trapped woylies (n≤19) at Whiteman Park Reserve in Perth, Western Australia, two days after a major bushfire and measured FCM concentration by enzyme immunoassay. Population-level comparisons of FCM were made between these samples and those collected in previous months (n≤58). While mean FCM varied by month of sample collection, it was not higher after the fire. We suggest that woylies may be able to maintain homeostasis through change (allostasis), at least in the period immediately after the fire. This is supported by our finding that FCM did not relate significantly to body condition or parasite load. Our results potentially highlight the physiological and behavioural adaptations of woylies to fire, which could be further explored in future studies