Epsilon Archive for Student Projects

Abstract

It is essential for biodiversity conservation and sustainable foraging to understand the ecological niches of edible ectomycorrhizal fungi. This study investigates, with the use of soil DNA metabarcoding data from the Swedish Forest Soil Inventory, how forest characteristics and soil properties influence the occurrence of species within the Boletaceae family and Suillus genus. The effects of the variables: stand age, tree species composition, soil pH, nitrogen availability (N:C ratio) and nitrogen deposition on fungal presence were analysed.
Generalized additive models (GAMs) were used to investigate the relationships between these variables and fungal occurrence across multiple taxonomic levels (family, genus, and species). In this study, it was found that tree species composition was the strongest predictor of fungal presence. The species within the genus Suillus were negatively associated with spruce, birch and other trees, supporting claims from previous literature stating that species within the genus Suillus are prone to choose pine as their host trees. In contrast, species within Boletaceae, such as Boletus edulis and genus Leccinum showed positive associations with spruce and birch. Boletaceae and Leccinum were more common in younger stands, while Suillus occurred more frequently in older stands.
Higher soil pH values were generally negatively associated with fungal occurrence, indicating a preference for acidic conditions. The N:C ratio showed a positive association with several taxa, suggesting the importance of a nutrient rich soil. Nitrogen deposition however, showed no significant effect on any of the fungal taxa. Spatial distribution patterns at larger taxonomic scales showed no strong geographic clustering, although several species exhibited a more restricted distribution.
This study demonstrates the effect of forest composition and soil properties on the occurrence of Boletaceae and Suillus species in Sweden. The findings of this study contribute to a better understanding of their preferred habitats and can therefore aid in forest management and conservation strategies, as well as improve the knowledge for recreational mushroom foraging.