Dominant community mycorrhizal types influence local spatial structure between adult and juvenile temperate forest tree communities

Abstract

Abstract Plant–soil feedback (PSF) is known to influence plant community composition, and recent work suggests that these effects may be regulated by traits related to mycorrhizal associations and phylogenetic relationships. However, there is a critical need to test the usefulness of these traits in predicting PSF outcomes in natural plant communities. To test for evidence of mycorrhizal and phylogenetic controls over PSF at both the species and community level, we examined the spatial relationship between adult and juvenile trees in stem‐mapped hardwood forest plots using point pattern analyses and linear mixed‐effect models. We found that spatial patterns of adult and juvenile trees, as well as overall adult tree recruitment, were significantly affected by the dominant mycorrhizal type of our forested communities, but were not influenced by the phylogenetic relationship between adult and juvenile trees. Additionally, PSF experienced by individual species was dependent on the mycorrhizal dominance of the surrounding community. Spatial patterns in communities dominated by arbuscular mycorrhizal trees reflected overdispersion between adult and juvenile trees (suggestive of negative PSF), while communities dominated by ectomycorrhizal trees reflected clustering (suggestive of positive PSF). Our findings indicate that PSFs are driven by the mycorrhizal associations of dominant trees, with effects of dominant community member traits on soil microorganisms and biogeochemistry ‘spilling over’ onto less abundant individuals in the community. Our research supports the use of whole‐community, mycorrhizal‐based frameworks for studying PSF in plant communities where multiple mycorrhizal types are present. A free Plain Language Summary can be found within the Supporting Information of this article.