When imperilled by a threatening process, the choice is often made to conserve threatened species on offshore islands that typically lack the full suite of mainland predators. While keeping the species extant, this releases the conserved population from predator-driven natural selection. Antipredator traits are no longer maintained by natural selection and may be lost. It is implicitly assumed that such trait loss will happen slowly, but there are few empirical tests. In Australia, northern quolls () were moved onto a predator-free offshore island in 2003 to protect the species from the arrival of invasive cane toads on the mainland. We compared the antipredator behaviours of wild-caught quolls from the predator-rich mainland with those from this predator-free island. We compared the responses of both wild-caught animals and their captive-born offspring, to olfactory cues of two of their major predators (feral cats and dingoes). Wild-caught, mainland quolls recognized and avoided predator scents, as did their captive-born offspring. Island quolls, isolated from these predators for only 13 generations, showed no recognition or aversion to these predators. This study suggests that predator aversion behaviours can be lost very rapidly, and that this may make a population unsuitable for reintroduction to a predator-rich mainland.

Earth's rapidly warming climate is propelling us towards an increasingly fire-prone future. Currently, knowledge of the extent and characteristics of animal mortality rates during fire remains rudimentary, hindering our ability to predict how animal populations may be impacted in the future. To address this knowledge gap, we conducted a

Planet Earth is entering the age of megafire, pushing ecosystems to their limits and beyond. While fire causes mortality of animals across vast portions of the globe, scientists are only beginning to consider fire as an evolutionary force in animal ecology. Here, we generate a series of hypotheses regarding animal responses to fire by adopting insights from the predator–prey literature. Fire is a lethal threat; thus, there is likely strong selection for animals to recognize the olfactory, auditory, and visual cues of fire, and deploy fire avoidance behaviours that maximize survival probability. If fire defences are costly, it follows that intraspecific variation in fire avoidance behaviours should correspond with variation in fire behaviour and regimes. Species and populations inhabiting ecosystems that rarely experience fire may lack these traits, placing ‘fire naive’ populations and species at enhanced extinction risk as the distribution of fire extends into new ecosystem types. We outline a research agenda to understand behavioural responses to fire and to identify conservation interventions that could be used to overcome fire naivety.

Aim: After environmental disasters, species with large population losses may need urgent protection to prevent extinction and support recovery. Following the 2019-2020 Australian megafires, we estimated population losses and recovery in fire-affected fauna, to inform conservation status assessments and management.Location: Temperate and subtropical Australia. Time period: 2019-2030 and beyond.Major taxa: Australian terrestrial and freshwater vertebrates; one invertebrate group. Methods:From > 1,050 fire-affected taxa, we selected 173 whose distributions substantially overlapped the fire extent. We estimated the proportion of each taxon's distribution affected by fires, using fire severity and aquatic impact mapping, and new distribution mapping. Using expert elicitation informed by evidence of responses to previous wildfires, we estimated local population responses to fires of varying severity. We combined the spatial and elicitation data to estimate overall population loss and recovery trajectories, and thus indicate potential eligibility for listing as threatened, or uplisting, under Australian legislation. Results:We estimate that the 2019-2020 Australian megafires caused, or contributed to, population declines that make 70-82 taxa eligible for listing as threatened;