Plants, soil, and coexistence: an alternative approach to modelling plant-soil feedback

Abstract

Abstract Background and Aims Plant-soil feedback (PSF) affects plant coexistence and diversity. Although the current paradigm provides a direct experimental method to quantify PSF and explains coexistence with varying levels of success, the emphasis on pairwise interactions hinders linking PSF to community patterns. Methods We propose a new framework emphasizing the role of individual plants in soil dynamics. Our framework suggests a common-garden experiment to quantify PSF which is species-specific rather than focused on species pairs, which require fewer treatment groups. We illustrate how data from such an experiment can be used to quantify PSF using simulated data of plant-soil dynamics. Results We show that the current approach is susceptible to mispredicting coexistence due to incomplete characterization of the timescale of soil conditioning. Our proposed framework remedies this issue and expands the realm of possible coexistence outcomes dependent on the soil's history. Our proposed experiments are designed to confront the implicit assumptions in current PSF research and reveal gaps in our understanding of how plants condition the soil. Conclusion The shift in focus from pairwise PSF measures to species-based soil conditioning offers a better path to linking PSF to plant coexistence and community structure, and to forecasting the effects of PSF under changing environments.