Communities of free-living organisms are shaped by processes operating within and among patches of habitat, whereas pathogen communities are shaped by analogous processes operating within and among hosts. Resource competition (R*) theory can describe dynamics within patches or hosts, and metacommunity dynamics describe competition–colonization trade-offs, extinction debts, and superinfection. However, models at this broader scale often assume instantaneous competitive exclusion in co-inhabited patches or co-infected hosts. Impacts of more gradual competitive exclusion on the abundance, distribution, and diversity of species are less clear. Here, we nest a general resource competition model within a metacommunity framework and manipulate the relative timescales for processes operating within and among patches/hosts. We focus on superinfection in pathogen communities. We compare cases where transmission depends on infection prevalence vs. the abundance of pathogens within hosts. Surprisingly, slowing the relative pace of competitive exclusion within hosts can decrease infection prevalence of the inferior competitor and increase prevalence of the superior competitor, depending on transmission and virulence. Slower within-host dynamics reduce the abundance of both pathogens within hosts and promote diversity at multiple scales: co-infections within individual hosts and co-occurrence in the host population. These results highlight surprising feedbacks that can emerge across scales and reinforce the rich cross-scale connections between community and disease ecology.
Bibliographical noteFunding Information:
This work was supported by National Science Foundation DEB 1556649 to EWS and ETB. LGS was supported by the James S. McDonnell Foundation grant 220020513 and NSF IOS 1556674 to A Shaw, ETB, and EWS. All authors helped design the model, led by ATS. Conversations with D. Tilman, C. Klausmeier, and A. Shaw also helped guide formulation of the model. ATS implemented the model and wrote the first draft of the manuscript. All authors contributed to revisions. Simulations were run at the Minnesota Supercomputing Institute.
© 2019 by the Ecological Society of America
- community ecology
- competitive exclusion
- disease ecology
- resource competition