Burning microorganisms: the responses of litter myxomycetes to different fire intensities in a tropical savanna.

Fire shapes the diversity and distribution of organisms inhabiting fire-prone ecosystems. Most studies focus on the responses of aboveground organisms, but fire also affects soil and litter microorganisms essential for nutrient cycling and decomposition, which has been poorly investigated. Here, we aimed to fill this gap by assessing the effects of experimentally controlled fires on the species richness, abundance, and composition of key litter microbial microorganisms, i.e. the myxomycetes. For this, we performed three controlled burns of distinct intensities: against the wind fire (low-intensity), L-shaped fire (Intermediate-intensity), and circular fire (High-intensity). We found that the response of myxomycetes to fire was related to the burning intensity, with decreasing diversity of litter myxomycetes with increasing fire intensity and a single species on the high-intensity fire. Of the 288 moist chambers prepared, 45.14% were positive, showing myxomycetes in the sporocarp, plasmodium and/or sclerotium stages. Considering only sporocarps, 37 records representing 24 species were obtained. Species richness varied among treatments, higher richness in the control area (15 species), followed by low-intensity (13 species), intermediate-intensity (2 species), and high-intensity (1 species) fire treatments. Overall, our results indicate that high-intensity fire events can be even more detrimental to the overall biodiversity of fire-prone ecosystems than previously thought, furtherly impacting the interplay between above- and below-ground nutrients and organisms.