Rainforest litter invertebrates decimated by high severity burns during Australia's gigafires

Climate change is increasing the frequency of extreme fires. In 2019–2020, fires burned 97 000 km2 native vegetation in south-eastern Australia, affecting many areas rainforest, which has historically less frequently. One year post-fires, we surveyed litter macroinvertebrates 52 temperate rainforest sites. Sites had experienced levels fire severity (unburnt, medium and high severity). We asked how affected: (1) macroinvertebrate habitats; (2) abundance taxa per unit area; (3) relative to habitat (volumetric density). also estimated loss across rainforests study region. High burns supported only a fifth volume canopy cover as unburnt sites, lower soil moisture higher herb cover. Medium were intermediate. Macroinvertebrate declined with burn severity: 26% sites; 80% that Patterns similar for all taxa, millipedes declining most. resulted up 1.90 million fewer hectare; 0.53 hectare rainforest. Across region, estimate 60 billion persisted alone. Volumetric densities marginally than suggesting nutrients may be more available post-fire, or persisting individuals become concentrated leaf litter. For desiccation-tolerant groups (e.g., amphipods), density declines reflect combined impact low reduced Many following fires, but substantial, differed their vulnerability. Longer-term monitoring required understand recovery trajectory impacts on ecological function.