Islands on fire: Fire and threatened species patterns across Australia's islands

Australia and its islands have a long history of fire, which has shaped their ecosystems and unique species. Fire patterns in Australia have changed since European settlement in 1788 with land use and climate changes. Australia has over 9000 islands, which serve as safe havens for threatened species conservation. Nevertheless, their recent fire histories and characteristics remains understudied. We used remote sensing and long-term governmental datasets to study spatiotemporal variation in fire characteristics across Australia's islands. We examined human activity and lightning patterns as predictors of fire characteristics on islands. We then examined the correspondence between island fire metrics and their threatened species richness. We found that a quarter of all Australian islands with an area over 1 km² for which remote sensing fire data was available (n = 167 islands) had at least 10 fire events over the past two decades. This includes large fires that burnt substantial island areas, such as the 2020 wildfires on K'gari (Fraser Island) and the 2019/2020 wildfires on Kangaroo Island. These fires burnt 31 % and 40 % of the islands, respectively. Human population size was an important predictor of fire intensity. Threatened species were associated with islands with higher fire intensities and larger burnt areas. While some Australian island species may benefit from fire, large and intense fires may lead to species declines and jeopardize the role of islands as safe havens and refuges for threatened species. Further knowledge sharing between researchers, practitioners, Indigenous peoples and additional stakeholders can support future management of fire and threatened species on islands.