Table 1 Stochastic vs. deterministic components of soil fungal community assembly in a lowland tropical rain forest in Amazonia

From: Seasonal dependence of deterministic versus stochastic processes influencing soil fungal community composition in a lowland Amazonian rain forest

Method

Result

Inference

Null models – distance vs. environmental (soil physico-chemical properties) decay

Significant distance decay in the rainy season and transition into dry season in community similarity*

Community assembly governed by stochastic processes in the rainy season and transition into dry season

Non-significant environmental decay in community similarity in all seasons

Significant distance decay and environmental decay in community similarity when considering SDP

Community assembly governed by both stochastic and deterministic processes at short distances

Null models – observed β-diversity vs. expected β-diversity

Pattern in ASV abundance x site matrix significantly different from null model:

• RC (dry season)

• SES (dry season)

• tNST (transition into dry season; dry season)

Community assembly primarily governed by deterministic processes in the dry season

Pattern in ASV abundance x site matrix not significantly different from null model:

• RC (rainy season; transition into dry season; SDP)

• SES (rainy season; transition into dry season; SDP)

• tNST (rainy season; SDP)

Community assembly primarily governed by stochastic processes in the rainy season, in the transition into dry season and at short distances

  1. * community similarity was calculated using abundance data, i.e., reads of amplicon sequence variants (ASVs).
  2. Stochastic processes may include stochasticity due to ecological drift and/or limited dispersal but also to unmeasured environmental variables linked to tree species-specific leaf morphology and chemistry.
  3. RC modified Raup–Crick dissimilarity metric, SES standardised effect size, tNST taxonomic normalised stochasticity ratio index, SDP sampling that considered short-distance patterns up to 6 m (4 plots per site; grain size 1 m2; site extent ca. 25 m2; 15 sites over a linear extent of 1.5 km)
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