Both ecological theory and empirical evidence suggest that negative frequency dependent
feedbacks structure plant communities, but integration of these findings has been limited.
Here we develop a generic model of frequency dependent feedback to analyze coexistence
and invasibility in random theoretical and real communities for which frequency dependence
through plant-soil feedbacks (PSFs) was determined empirically. We investigated community
stability and invasibility by means of mechanistic analysis of invasion conditions and numerical
simulations. We found that communities fall along a spectrum of coexistence types ranging
from strict pair-wise negative feedback to strict intransitive networks. Intermediate community
structures characterized by partial intransitivity may feature “keystone competitors” which disproportionately
influence community stability. Real communities were characterized by stronger
negative feedback and higher robustness to species loss than randomly assembled
communities. Partial intransitivity became increasingly likely in more diverse communities.
The results presented here theoretically explain why more diverse communities are characterized
by stronger negative frequency dependent feedbacks, a pattern previously encountered
in observational studies. Natural communities are more likely to be maintained by strict negative
plant-soil feedback than expected by chance, but our results also show that community
stability often depends on partial intransitivity. These results suggest that plant-soil feedbacks
can facilitate coexistence in multi-species communities, but that these feedbacks may also initiate
cascading effects on community diversity following from single-species loss.
Mack KML, Eppinga MB, Bever JD (2019)
Plant-soil feedbacks promote coexistence and
resilience in multi-species communities. PLoS ONE