Frameworks for identifying priority plants and ecosystems most impacted by major fires

Globally, many species and ecosystems are experiencing landscape-scale wildfires ("megafires') and these events are predicted to increase in frequency and severity as the climate warms. Consequently, the capability to rapidly assess the likely impacts of such large fires and identify potential risks they pose to the persistence of species and ecosystems is vital for effective conservation management. In this review, we propose novel frameworks to identify which plant species and ecosystems are most in need of management actions as a result of megafires. We do this by assessing the impacts of a fire event on plants and ecosystems in the context of the whole fire regime (current fire event combined with recent fire history) and its interactions with other threatening processes, rather than simply considering the amount of habitat burnt. The frameworks are based on a combination of key species' traits related to mechanisms of decline, components of the fire regime that are most likely to have adverse impacts on species or ecosystem recovery, and biotic and environmental factors that may amplify fire impacts or pose barriers to post -fire recovery. We applied these frameworks to guide management priorities and responses following the extensive 2019/2020 fires in southern Australia, and we illustrate their application here via a series of worked examples that highlight the various mechanisms of post -fire decline the frameworks address. The frameworks should be applicable to a broader range of fire-prone biomes worldwide. Our approach will (1) promote the development of foundational national datasets for assessing megafire impacts on biodiversity, (2) identify targeted priority actions for conservation, (3) inform planning for future fires (both prescribed burning and wildfire suppression), and (4) build awareness and understanding of the potential breadth of factors that threaten plants and ecosystems under changing fire regimes.