High site fidelity and reduced survival of a mycophagous mammal after prescribed fire

Abstract

Fire offers both opportunities and risks for wildlife. Its impact will depend on the fire’s scale, how it alters key resources and how animals move. Understanding how wildlife respond to fire is crucial as climate change is predicted to increase wildfire risk and will likely result in more frequent prescribed fire to reduce wildfire risk. Invasive predators and inappropriate fire regimes in south-eastern Australia threaten the long-nosed potoroo (Potorous tridactylus), a vulnerable marsupial often residing in areas frequently exposed to fire. The cumulative impacts of fire and predation may increase the threat to P. tridactylus after fire, as predators can be more effective in the immediate post-fire environment and P. tridactylus is often dependent on thick ground cover. We present a before-after control-impact experiment describing the influence of prescribed fire on P. tridactylus. We fitted GPS collars to 52 individuals at nine independent sites to test if exposure to prescribed burning reduced their survival or altered their movement behavior. Prescribed fire reduced P. tridactylus survival, yet range size and diffusion (movement) rate remained largely unaffected. With limited fire exposure, P. tridactylus tended to continue using burnt areas whereas activity became restricted to unburnt areas when larger proportions of their home range burnt. Site fidelity was very high - individuals rarely moved their home ranges after fire, regardless of fire exposure. Our results suggest recently burnt areas may be particularly dangerous for P. tridactylus: areas that can be attractive yet confer lower fitness outcomes. P. tridactylus may benefit from smaller fire scars, retention of structurally complex vegetation, and integrating invasive predator control with prescribed burning.