Airborne fungal DNA is used as a tool to estimate fungal diversity inhabiting various ecosystem substrates. Understanding the spatial dynamics of airborne DNA assemblages is necessary to link airborne DNA assemblages with local fungal communities. In this study, we aimed to clarify how vegetation, which influences local fungal communities, and spatial distance shape the spatial structure of airborne DNA assemblages. In a continuously forested landscape of approximately 10 km, we selected ten stands across three vegetation types and monitored the airborne DNA assemblages in these stands for over five months. Although vegetation significantly influenced the DNA assemblages, temporal variation exceeded spatial variation. Little overlap in the assemblages was observed, even between the closest stands that were approximately 20 m apart, implying a limited dispersal even at this distance. By focusing on a heterogeneous environment, we demonstrated that airborne DNA assemblages show dynamics at a smaller spatial scale than previously recognized.
Ascension Island is a remote oceanic island that was a volcanic desert prior to human colonisation. In the 19th century, an artificial cloud forest was established by a military garrison to improve the scarce water supply. Using ITS metabarcoding of topsoil environmental DNA, we compared the fungal communities of the desert and the Green Mountain cloud forest. Forest soils had higher total nitrogen and carbon, and lower pH than desert soils. Fungal richness was higher in forest soils and ordination analysis revealed distinct fungal communities in each habitat. Both habitats contained a high percentage of unclassified fungal OTUs, implying the presence of native/endemic fungal flora, with a shift from Ascomycota in the desert to Asco-Basidiomycota in the forest. Indicator species analysis revealed habitat- and vegetation-specific fungal taxa, and the presence of cosmopolitan fungi in forest and unknown fungi in the desert soils, suggesting reshaping of fungal communities due to the afforestation.
The fungal mycelium is a dynamic structure capable of complex spatial responses, yet its spatial responses to anthropogenic stressors are rarely tackled, despite the often-heterogeneous distribution of stressors. In this study, 23 saprotrophic fungal isolates were exposed to a localized copper source, and spatial mycelial responses were assessed through qualitative morphological scoring and compared with conventional biomass and mycelial extension metrics. This approach revealed diverse intra- and interspecific morphological responses. Most fungi showed asymmetric inhibition near the copper while maintaining growth elsewhere, indicating spatial containment. Three inhibition front morphologies, concave, convex, and straight, suggest different underlying mechanisms, including hyphal tip inhibition and structural growth constraints. Barrage-like formations, even in early-diverging Mucoromycota, point to conserved spatial defense strategies. Other responses included vertical growth redirection, global suppression without local inhibition, and reproductive shifts. These findings emphasize a need for spatially explicit approaches for predicting effects of environmental pollution on fungal biodiversity.
Extinction risk assessment of the world's funga lags far behind that of flora and fauna, impeding inclusion in conservation policy and action. Prediction and automation have helped accelerate Red Listing of plants, facilitating prioritization of taxa for assessment and reducing the manual input required. Similar approaches for fungi could help address their extreme underrepresentation on the Red List. We used Bayesian logistic regression modelling and an automated assessment pipeline to identify and rapidly assess 715 species of North American macrofungi confidently predicted to be Least Concern. However, fundamental data are lacking for risk prediction for many fungi: only one in twenty species analysed could be classified as confidently Least Concern. Our workflow could facilitate increased coverage of fungi on the Red List. Nonetheless, continued investment in assessing potentially threatened fungi is essential for improving the accuracy of future predictions and, more importantly, for guiding conservation action for species at risk.
