Abstract Trees associated with arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) fungi are commonly thought to dominate in nutrient‐rich and nutrient‐poor environments, respectively. However, the mechanisms underlying this pattern remain poorly understood. Here, two potential drivers were evaluated: (i) environmental filtering , where soil fertility shapes tree species dominance by regulating growth and mortality; and (ii) tree‐mediated regulation , where trees modify soil conditions in ways consistent with their mycorrhizal strategy. The importance of these drivers was tested using a comprehensive 15‐year dataset for a 25‐ha temperate forest dynamics plot, including data on individual trees, soil properties, leaf litter production and leaf litter nutrient content. Generalized linear mixed models were employed to estimate the effects of initial soil properties on tree mortality and growth. Leaf litter disposal models and structural equation models were utilized to evaluate the effects of mycorrhizal dominance on changes in soil properties over time. Consistent with the environmental filtering hypothesis, EcM tree mortality increased with soil fertility, while growth declined. However, EcM dominance did not drive soil impoverishment as predicted (i.e. tree‐mediated regulation hypothesis). Instead, EcM dominance was associated with the accumulation of total phosphorus and with reduced losses of available nitrogen and phosphorus over time. Furthermore, leaf litter stoichiometry rather than absolute nutrient levels mediated the effects of EcM dominance on soil physicochemical properties. Synthesis . These results highlight that environmental filtering largely contributes to the distribution of mycorrhizal‐associated trees along a soil fertility gradient. Although tree‐mediated regulation did not directly shape tree distributions, it tended to modify soils in directions opposing their associated niche. This study refines our understanding of plant–soil feedback mechanisms, highlighting that community assembly is primarily governed by local soil conditions, whereas plant‐induced modifications develop more slowly through time.
Zhu et al. (Sun,) studied this question.