Australian bushfire genetics
The use of genetic analyses has become ubiquitous in conservation planning and management. Typically, such analyses are employed at the species-level, though as genetic data accrue, it is now possible to consider the genetic composition of multiple species across landscapes. Such macrogenetic perspectives can reveal the potential genetic ramifications of extreme disturbance events, such as the catastrophic Australian 'Black Summer' wildfires of 2019–2020. This event severely impacted forested habitats and fauna across much of eastern Australia – but whether there were impacts upon genetically distinct populations, or significant erosion of high diversity populations across species, was not known. Here, we present a conservation macrogenetics framework to examine the potential genetic impacts of this large-scale disturbance. Using hundreds of samples spanning dozens of frog, mammal, and reptile species, we first demonstrate how reduced-representation sequencing can be aggregated across species to describe the distribution of genetic diversity across a landscape. We then show that, whilst variable across the study area, these unprecedentedly extensive fires generally burnt areas where genetic diversity of sampled taxa was higher than for unburnt areas . Additionally, areas with high concentrations of evolutionarily distinct and short-range species were disproportionally represented in burnt regions.  Potential cross-taxonomic adverse effects were greatest in Australia's southeast and central eastern seaboard regions. More broadly, our work demonstrates how the conservation genetics principles applied at a species level can be expanded to landscapes, whilst accounting for the challenges that arise when aggregating across taxonomic groups, thus improving our understanding of the overall impacts of large-scale disturbance events on genetic diversity.