Plant–soil feedback persists beyond host death to shape density-dependent plant competition
Journal
Plant and Soil
ISSN
0032-079X
1573-5036
Date Issued
2026-07-15
Author(s)
Abstract
Background and Aims: Plant–soil feedback (PSF) shapes plant competition, yet classic PSF experiments often overlook the density dependence and temporal complexities of PSFs, especially after host death. We ask whether microbial effects vary after host death and mediate density dependence in seedling competition.
Methods: We combined forest census data from a subtropical forest with a density-gradient greenhouse experiment to evaluate how microbial legacies influence seedling competitive outcome. We used two tree species (Engelhardia roxburghiana and Machilus zuihoensis) as model species. In 2023, we collected soil inocula from living and dead trees (died between 2014 and 2019) with unsterilized and sterilized treatments. We applied invasion analysis to infer seedling competitive outcomes and used bootstrapping to evaluate uncertainty.
Results: Soil microbial communities shaped seedling competitive outcome, favoring E. roxburghiana. We found a consistent exclusion of M. zuihoensis by E. roxburghiana when using unsterilized soils collected from living and dead hosts, indicating that PSF persists for over 4–9 years after host death. In contrast, we found E. roxburghiana persisted in sterilized inoculum from living but not from dead hosts, suggesting underlying abiotic changes which might be masked by microbial effects. Moreover, we found significant evidence that soil microbes can mediate negative, nonlinear density dependence in seedling competition.
Conclusion: We provide experimental evidence of persistent microbial legacies that shape plant competition in a subtropical forest. Our study demonstrates how integrating field-based census data with density-gradient experiments and explicit uncertainty estimation can better capture the temporal dimensions, complexities of density dependence, and uncertainties of PSF.
Subjects
Coexistence
Forest dynamic plot
Invasion growth rate
Legacy effect
Nonlinear density dependence
Subtropical forest
Publisher
Springer Science and Business Media LLC
Type
journal article