Cyclic population dynamics and density-dependent intransitivity as pathways to coexistence between co-occurring annual plants

• Published in: The Journal of ecology 2018-05, Vol.106 (3), p.838-851
• Main Authors: Stouffer, Daniel B., Wainwright, Claire E., Flanagan, Thomas, Mayfield, Margaret M.
• Format: Article
• Language: English
• Subjects: Annual; annual‐plant models; Biodiversity; Capacity; Coexistence; Community composition; density‐dependent intransitivity; Dynamics; Empirical analysis; Environmental conditions; environmental heterogeneity; Exploration; fixed‐point equilibria; Flowers & plants; Interactions; Monoculture; Monoculture (aquaculture); mutual invasibility; oscillating population dynamics; Periodic variations; Periodicity; Plant communities; Plant diversity; plant population and community dynamics; Plant species; Population; Population density; Population dynamics; Predators; Prey; Solutions; Special Feature-Research Articles; Species; Species diversity
• ISSN: 0022-0477; 1365-2745
• DOI: 10.1111/1365-2745.12960

1. Recent studies have brought renewed attention to the importance of complex species interactions—notably intransitive interactions—to patterns of plant community diversity. One underappreciated avenue through which intransitivity can occur is through cyclic population dynamics. Although such cyclic intransitive relationships have been extensively studied in predator-prey systems, evidence of their importance in competitive communities, notably plant communities, is more limited. Most studies of coexistence in plant communities assume fixed-point coexistence even while utilising models that allow for cyclic population dynamics. 2. In this paper, we explore the potential for density-dependent, cyclic population dynamics and intransitivity in a model for annual plants. We then examine how these density-dependent cycles impact mutual invasibility and ultimately stable coexistence between plant species pairs. We do this using data collected from four co-occurring annual plant species living in natural wildflower communities in SW Western Australia. To maximise the number of biologically plausible pathways by which coexistence mediated by density-dependent cyclic intransitivity can occur, we use an annual plant model that allows for competitive direct interactions, facilitative direct interactions and higher-order interactions between species. 3. Results from our empirically parameterised model suggest that monocultures of all four focal species can have cyclic solutions with periodicity