Short-term soil fungal community dynamics following fire in mediterranean climate-type banksia woodlands

Fire is a dominant ecosystem process in many Mediterranean climate type ecosystems, and is predicted to increase in severity and frequency, shifting away from previous regimes in many regions. Responses of flora and fauna to fire are relatively well studied, but less is known about the responses of belowground microbiota. We quantified soil fungal dynamics over the first 12-15 months after fire, focusing on attributes of the fire regime (season, interval, severity). Soil samples were collected from three sites in a threatened woodland ecosystem in southwestern Australia, a Mediterranean-type climate region. Fungal taxa were identified via high throughput sequencing of the ITS subregion and taxonomy assigned using reference databases. Richness, diversity, abundance, community composition, and functional groups were quantified. Over the post-fire sampling period, richness and diversity declined and soil fungal community composition changed significantly throughout the sampling period, with family level taxa and functional groupings experiencing the most change. Through the sampling period, an increase in saprotrophic and endophytic fungi was observed, along with a decrease in all pathogenic fungi. We found that the post-fire fungal community is quite dynamic in the first 12-15 months after fire. We found little effect of fire interval or fire season, though our inference was limited. Our work contributes to putting belowground biota into the same conceptual frameworks as aboveground taxa and serves to inform fire managers in fire-prone Mediterranean climate type regions.