Mutualist and pathogen traits interact to affect plant community structure in a spatially explicit model

Andrew Dobson,Daniel F Petticord,Edward Allen Herre,John W Schroeder,Scott A Mangan

doi:10.1038/s41467-020-16047-5

Abstract

Empirical studies show that plant-soil feedbacks (PSF) can generate negative density dependent (NDD) recruitment capable of maintaining plant community diversity at landscape scales. However, the observation that common plants often exhibit relatively weaker NDD than rare plants at local scales is difficult to reconcile with the maintenance of overall plant diversity. We develop a spatially explicit simulation model that tracks the community dynamics of microbial mutualists, pathogens, and their plant hosts. We find that net PSF effects vary as a function of both host abundance and key microbial traits (e.g., host affinity) in ways that are compatible with both common plants exhibiting relatively weaker local NDD, while promoting overall species diversity. The model generates a series of testable predictions linking key microbial traits and the relative abundance of host species, to the strength and scale of PSF and overall plant community diversity.

Highlights

Empirical studies show that plant-soil feedbacks (PSF) can generate negative density dependent (NDD) recruitment capable of maintaining plant community diversity at landscape scales
We found that microbial community dynamics can create a correlation between host abundance and PSF, such that common
Previous work has explored the role of plant-soil feedback (PSF) as a process structuring plant communities[6,13,19], but a lack of detailed mechanistic PSF models has limited our understanding of the causes and consequences of PSF for plant community structure

Summary

Introduction

Empirical studies show that plant-soil feedbacks (PSF) can generate negative density dependent (NDD) recruitment capable of maintaining plant community diversity at landscape scales. We find that net PSF effects vary as a function of both host abundance and key microbial traits (e.g., host affinity) in ways that are compatible with both common plants exhibiting relatively weaker local NDD, while promoting overall species diversity. The model generates a series of testable predictions linking key microbial traits and the relative abundance of host species, to the strength and scale of PSF and overall plant community diversity. Such studies have suggested that the strength of PSF determines plant relative abundance; common species are common because they experience weaker net PSF effects Given this apparent contradiction, the mechanisms underlying PSF effects on host species diversity and relative abundance require an explicit theoretical framework that will generate predictions for clear empirical tests. This potential for pathogens and mutualists to differ in life history traits underscores the importance of considering how both mutualists and pathogens independently affect feedback

Methods

Results

Conclusion