Fungi as Ecosystem Engineer Species of the Pannonian Grasslands: The Effect of Fungal Fairy Rings on Grassland Vegetation

Fungal fairy rings (FFRs) are circular patterns primarily formed by basidiomycete fungi. These structures significantly influence grassland ecosystems by mediating nutrient cycling, altering soil microbial communities, and driving shifts in plant community composition. The present study investigates FFR formed by Agaricus xanthodermus in a Pannonian sandy grassland, with a focus on vegetation structure, productivity, and diversity. Field surveys conducted along transects across FFR quantified plant species cover, height, and additional ecological parameters. The findings demonstrate that FFR alters species dominance, reduces diversity at the ring edge, and based on ecological indicator values of plant species it increases soil nitrogen, and modify the movement of water and nutrients within the soil. Collectively, these results suggest that FFRs function as ecosystem engineers, shaping ecological processes and affecting the agricultural potential of semi-natural grasslands.