Life-history trade-offs among species are major drivers of community assembly. Most studies investigate how trade-offs promote deterministic coexistence of species. It remains unclear how trade-offs may instead promote historically contingent exclusion of species, where species dominance is affected by initial abundances, causing alternative community states via priority effects. Focusing on the establishment-longevity trade-off, in which high longevity is associated with low competitive ability during establishment, we study the transient dynamics and equilibrium outcomes of competitive interactions in a simulation model of plant community assembly. We show that in this model, the establishment-longevity trade-off is a necessary but not sufficient condition for alternative stable equilibria, which also require low fecundity for both species. An analytical approximation of our simulation model demonstrates that alternative stable equilibria are driven by demographic stochasticity in the number of seeds arriving at each establishment site. This site-scale stochasticity is affected only by fecundity and therefore occurs even in infinitely large communities. In many cases where the establishment-longevity trade-off does not cause alternative stable equilibria, the trade-off still decreases the rate of convergence toward the single equilibrium, resulting in decades of transient dynamics that can appear indistinguishable from alternative stable equilibria in empirical studies.
Bibliographical noteFunding Information:
We thank Eyal Ben-Hur, Inga Dirks, and Ove Eriksson for providing us with raw data from their studies for estimation of the fecundity range of annual and perennial species; Jean-Francois Arnoldi, Marc Cadotte, Callie Chap-pell, Po-Ju Ke, Jennifer Lau, Jesse Miller, Erin Mordecai, Egbert van Nes, Suzanne Ou, and two anonymous reviewers for providing comments; and Callie Chappell for assistance in improving figure 1. This work was supported by the Rothschild Fellowship (N.D.) and the Terman Fellowship of Stanford University (T.F.).
© 2021 by The University of Chicago.
- Alternative stable states
- Annual plants
- Competition-colonization trade-off
- Priority effects
- competition-colonization trade-off
- priority effects
- alternative stable states
- annual plants