Independence Effects of Heat and Ash on Forest Soil Nematode-Trapping Fungi Communities

Heat input and ash residues are main components of vegetation fire disturbances. Understanding the distinct impacts of heat and ash on soil microorganisms is crucial to comprehend and predict the induced changes in soil ecosystem composition and dynamics following different types of fire disturbances. This study's main goal was to track the dynamic shifts in the community of soil nematode-trapping fungi (NTF) following the separate disturbances of heat and ash by means of a specifically designed experiment conducted in the field. Four simulated fire treatments, one treatment reproducing natural burning, and one control treatment were taken into account. Every ten days following the disturbance, soil samples from each treatment were collected, and soil NTF and physicochemical characteristics were measured. The results showed that: (1) Heat drastically decreased the number of strains and heavily altered the NTF community, but it also encouraged the emergence of new NTF species. Instead, no overt changes were observed in the treatment that just experienced the addition of ash on the soil. (2) When compared to treatments that received only heat input, the lower strain count of NTF recovered more quickly in the natural burning treatment which was affected by both heat and ash input. These findings suggest that the disruptive effect of fire heat on soil NTF biomass may be counterbalanced by the emergence of new species and the repairing capabilities of new nutrients introduced by ash residue. In the future, both conventional and cutting-edge techniques should be considered in research designs to better understand the ecological role of fire disturbances occurring at different intensities, as well as the mechanisms that make soil ecosystems resilient to fire, in particular the role of new species.