Dynamics of Age-Structured Predator-Prey Populations in Space: Asymmetrical Effects of Mobility in Juvenile and Adult Predators

Abstract

In many natural predator-prey systems, there are differences in mobility between individual predators and prey. In this paper, we use individual-based models to examine how differences in mobility of age-structured predator populations affect the spatial and temporal dynamics of predator-prey populations. Predators and prey in our model do not possess any behavioral rules for aggregation, and spatial heterogeneity is internally generated from the interaction among individuals (i.e. populations are not externally subdivided into patches). We show that differential mobility by juvenile and adult predators can have an asymmetrical effect on stability when prey mobility is relatively limited. Increasing the mobility of adult predators destabilizes predator-prey dynamics, while changing juvenile mobility does not. We also investigate stage-structured dispersal by predators and show that, contrary to general conclusions from metapopulation theory, widespread dispersal of predator offspring can actually stabilize dynamics and lead to novel patterns of spatial organization of predator and prey populations. With limited mobility of individuals and local offspring production, stability arises because of the asynchrony of dynamics among many different regions of the lattice. Dispersing predator offspring (i.e. decoupling local recruitment from local predator-prey interactions) produces stability of local regions and large-scale spatial patterning.