Dispersal may limit the occurrence of specialist wood decay fungi already at small spatial scales

We used species‐specific spore traps to measure airborne dispersal of the wood decay fungus Phlebia centrifuga (spore size 6.5–9 × 2.5–3 μm) up to 1000 m distance from a point source. We fitted two simple dispersal models, an empirical power law model and a semi‐mechanistic diffusion model to the data using the Bayesian approach. The diffusion model provided a better fit than the power law model which underestimated deposition at 3–55 m and overestimated deposition at longer and shorter distances. Model fit improved by allowing overdispersion, suggesting that spores are not dispersed independently but wind can transport spores in groups inside discrete air packages up to considerable distances. Using the fitted diffusion model and available information on the establishment rates of wood‐decay fungi, we examine the distance up to which colonisation from a single fruit body is likely to occur. We conclude that the diluting effect of distance and low establishment success make the occurrence of P. centrifuga dispersal limited possibly already at the distance of tens of metres and very probably at a few hundred metres from the nearest fruit body, despite the fact that under favourable conditions a high proportion of the spores can disperse considerably further. This conclusion is likely to hold generally for those fungal species that inhabit fragmented landscapes, have specialised resource and habitat requirements, and have similar spore size and other dispersal traits as P. centrifuga.