DuckeFungi_ASV_dist_ID_function_20220825.xlsx

High tree species diversity in tropical rain forests and rainfall seasonality contribute to large spatio-temporal variability in available resources for soil microbial communities. How the contribution of deterministic vs. stochastic processes to the assembly of these communities varies in space and time remains yet to be quantified so that soil microbial community responses to climate change may be projected.To address this knowledge gap, we characterised the spatio-temporal composition of soil fungal communities from the plot to the stand scales in a topographically homogeneous area in a tropical rain forest in central Amazonia. Doing so, we excluded obvious environmental gradients so as not to mask the detectability of potential mechanisms of community assembly linked to the intrinsic tree diversity of tropical rain forests. We then related fungal communities to seasonal patterns and spatial variability in geographic and soil characteristics.Soil fungal communities showed a greater turnover in space than in time. The relative contribution of stochastic and deterministic processes to community assembly was related to season, with stochastic processes, including potential dispersal limitation and ecological drift dominating in the rainy season, and deterministic processes, such as speciesselection dominating in the dry season. The results indicate that seasonality is likely to be related to the temporary accumulation of tree species-specific litter during the litterfall peak in the dry season, could define a deterministic environment that fades away after the start of the rainy season.Our study highlights the importance of spatial heterogeneity in the absence of environmental gradients and its relationship with seasonal patterns that modulate spatial heterogeneity and contribute to environmental determinism vs. stochasticity for fungal community assembly in tropical rain forests. This baseline may serve for assessing deviations in community patterns caused by changes in biotic interactions with above-ground vegetation, such as those resulting from shifts in taxonomical/functional composition of trees driven by climate change.