Temporal distance decay of similarity of ectomycorrhizal fungal community composition in a subtropical evergreen forest in Japan

Community compositions of ectomycorrhizal (ECM) fungi are known to show spatial distance decayof similarity, which arises from both deterministic niche-based processes and stochastic spatial-based processes (e.g. dispersal limitation). Recent studies have highlighted the importance of incorporating the spatial-based processes in the study of community ecologyof ECM fungi. However, few studies have investigated the temporal distance decayof similarity of ECM fungal communities. More specifically, the role of stochastic temporal-based processes, which could drive the temporal distance decayof similarity independently of niche-based processes, in the temporalvariation of the communities remains unclear. Here we investigated ECM fungi associated with roots of Castanopsis sieboldiiat 3-month intervals over a 2-year period. We found that dissimilarity of the ECM fungal community composition was significantly correlated with temporaldistance but not with environmental distance among sampling dates. Both climatic and temporalvariables significantly explained the temporalvariation of the community composition. These results suggest that temporalvariations of ECM fungi can be affected not only by niche-based processes but also by temporal-based processes. Our findings imply that priority effectsmay play important roles in the temporalturnover of ECM fungal community at the site.