Long-term post-fire recovery of an oribatid mite assemblage: A case study from a temperate coniferous forest

Wildfire represents a significant natural disturbance factor in forest ecosystems expected to further increase in importance due to global climate change. It has a detrimental short-term impact on soil biota, but much less is known about its long-term effects, especially on soil mesofauna. Our study compared oribatid assemblages of the forest floor in moderately-burned forest sites along a post-fire chronosequence (8 fire history classes covering 0–110 years since fire) with near-by reference sites without fire history. All sites were situated on acidic soils in the Central European Elbe Sandstone Mountains (Bohemian Switzerland National Park, NW Czechia), mostly covered by pine and spruce forests. Data were analysed using linear mixed-effect models. We found a substantial impact of fire on oribatid assemblages. Whereas lower densities were observed for the first few years after a fire only, changes in assemblage feeding guilds persisted over at least four decades. Shifts towards smaller body size, parthenogenesis and fungivory at burned sites compared to larger body size, sexual reproduction and detritivory in unburned controls implied changes in assemblage functioning. The changes in functional traits, which correspond to previous research findings on the recovery of oribatid mites after clear-cutting, underscore a more universal pattern of post-disturbance development.