Fairy rings caused by a killer fungus foster plant diversity in species‐rich grassland

Abstract

Questions: Does the fairy ring fungus Agaricus campestris affects spatial distribution of co-existing plant species? Is ring development related to changes of soil physical, chemical, enzymatic and microbiological properties? What are the causes of weakening and subsequent luxuriance of vegetation during fairy ring dynamics in the soil? Location: Species-rich, mowed calcareous grassland, central Italy (43° 17′26″ N, 12° 51′29″ E). Methods: Fairy rings were monitored for total plant biomass, species richness and composition in four zones: external grassland (OUT), fungal front (FF), area with flourishing vegetation (BELT) and internal grassland (IN). In each zone, 17 soil parameter were analysed: physical and chemical properties (water-holding capacity, pH, electrical conductivity, organic C, Olsen P, total N, NH 4 +, NO 3 -, hydrophobicity and cyanide concentration), total enzyme activity (FDA) and microbiological features (community-level physiological profile using BIOLOG EcoPlates ™, microbial biomass, fungal mycelium, culturable actinomycetes, bacteria and fungi). A bioassay was performed to evaluate responses of three co-existing species (Bromus erectus, Cynosurus echinatus and Centaurea ambigua) growing on soil collected from different fairy ring zones. Results: Plant species composition dramatically changed in response to fairy ring development, with disappearance of most grassland species in the ring-affected area. Plant biomass and species richness were higher in OUT and IN areas, and lowest in FF. Profound changes in soil properties occurred after fungal passage, with consistent reductions of C and N content and increases of FDA and microbial physiological profiles. Soil from the FF zone had remarkable increases of mineral N forms, electrical conductivity and hydrophobicity, with no trace of cyanide. The bioassay showed species-specific responses to different soil types. Conclusions: This study provides evidence that the spread of fairy ring fungi, coupled with a reduction of perennial plant cover, creates empty niches for many short-lived species

Ability of fungi isolated from plastic debris floating in the shoreline of a lake to degrade plastics

“…Within the zone of most intense fungal growth, the grass is often killed, and this effect has been attributed to a lack of moisture and to hydrocyanic acid produced by the fungus [ 45 , 46 ]. The occurrence of fairy rings in natural vegetation has simultaneous contrasting effects of both stimulation and a parasitisation of plant species in adjacent zones, producing concentric regular bands of lush and scorched vegetation [ 47 ]. In soils colonized by M .…”

Regime Shift by an Exotic Nitrogen-Fixing Shrub Mediates Plant Facilitation in Primary Succession

“…Values of the water drop penetration time > 1 h indicate that below-canopy soils are extremely hydrophobic [ 73 ]. It is well known that soil microbes, such as fairy-ring forming fungi [ 52 , 74 ], as well as the biochemical quality of soil organic matter [ 75 ] may contribute to produce soil water repellency. Previous studies reported that sandy texture, low pH and high organic C content are all factors that promote the development of soil water repellency [ 73 , 76 ].…”

Spiral and Rotor Patterns Produced by Fairy Ring Fungi

“…Thus, the dispersal ecology of fairy ring fungi is not conducive to generating the linear biomass fronts needed to induce spiral formation under ‘normal’ conditions. We note, however, that despite the infrequent observation of spirals, incomplete fairy rings (fairy arcs), with free edges are commonly seen and widely reported [ 3 , 7 ]. It is unclear whether the widespread observation of free-edges that do not rotate poses a fundamental challenge to the predictions of the Davidson model, or whether observed arcs arose from processes that would not be expected to create spirals (e.g.…”