Evolution in one or more species can alter the ecological dynamics of communities. For example in predator-prey systems, predator-prey coevolution can effectively reverse predator-prey cycles and drive cycles where peaks in predator density precede peaks in prey density. It is currently unclear how the effects (co)evolution has on community-level dynamics depend on the amount of genetic variation in each population. Using an eco-evolutionary predator-prey model, I show how system stability depends on the amounts of genetic variation in the predator and prey populations. My approach decomposes the stability of the whole system into an ecological component, evolutionary components, and eco-evolutionary components. The approach then determines the strengths of the contributions of each component to the stability of the system and how those strengths depend on the amount of genetic variation in each species.
Results/Conclusions
My approach identifies four general mechanisms through which eco-evolutionary systems are destabilized and the necessary amounts of genetic variation in each species. Destabilization can occur via (a) instability of the ecological subsystem (low genetic variation in both species); (b) instability of the evolutionary subsystem (high genetic variation in one or both species); (c) instability of an eco-evolutionary subsystem (high genetic variation in one or both species); or (d) different strengths of stabilities of the ecological, evolutionary, and eco-evolutionary subsystems (intermediate genetic variation in one or both species). These mechanisms generalize to systems with any number of species and any number of evolving traits. Hence, this theory provides a way to categorize how interactions between ecological and evolutionary processes determine the overall stability of a community. This also allows one to categorize population cycles based on the underlying driving mechanism (e.g., eco-driven cycles vs. evo-driven cycles).