Environmental context alters plant-soil feedback effects on plant coexistence

Area of Science:

• Ecology
• Plant Biology
• Microbial Ecology

Background:

• Plant-soil feedbacks (PSF) mediate plant competition via microbial loops.
• Environmental context dependencies of plant-microbe interactions are often overlooked in coexistence studies.

Purpose of the Study:

• To assess how context-dependent plant-microbe interactions influence plant coexistence using modern coexistence theory.
• To identify which species interactions are most affected by environmental context-dependencies.

Main Methods:

• Developed a plant-soil feedback model incorporating environmental context-dependencies.
• Analyzed the impact of linear environmental effects on nonlinear changes in niche differences and fitness ratios.
• Simulated invasion dynamics of garlic mustard (Alliaria petiolata) using context-dependent PSF.

Main Results:

• Microbial impacts on fitness ratios were more significant than direct plant-plant interactions.
• Environmental context-dependencies caused nonlinear shifts in coexistence predictions, leading to competitive exclusion or priority effects.
• Environmental dependence of PSF may explain invasion dynamics of garlic mustard across regions.

Conclusions:

• Context-dependent plant-soil feedbacks, particularly microbial influences, play a crucial role in altering plant fitness ratios and coexistence outcomes.
• Environmental gradients can nonlinearly modify plant-soil feedbacks, leading to complex community dynamics.
• Integrating context-dependent PSF into coexistence theory is essential for understanding spatial and temporal variations in plant communities.