Spore dispersal of basidiomycete fungi at the landscape scale is driven by stochastic and deterministic processes and generates variability in plant-fungal interactions

Fungi play an important role in plant communities and ecosystem function. As a result, variation in fungal community composition can have important consequences for plant fitness. However, there are relatively few empirical data on how dispersal might affect fungal communities and the ecological processes they mediate. We established sampling stations across a large area of coastal landscape varying in their spatial proximity to each other and contrasting vegetation types. We measured dispersal of spores from a key group of fungi, the Basidomycota, across this landscape using qPCR and 454 pyrosequencing. We also measured the colonization of ectomycorrhizal fungi at each station using sterile bait seedlings. We found a high degree of spatial and temporal variability in the composition of Basidiomycota spores. This variability was in part stochastic and in part explained by spatial proximity to other vegetation types and time of year. Variation in spore community also affected colonization by ectomycorrhizal fungi and seedling growth. Our results demonstrate that fungal host and habitat specificity coupled with dispersal limitation can lead to local variation in fungal community structure and plant-fungal interactions. Understanding fungal communities also requires explicit knowledge of landscape context in addition to local environmental conditions.