Ecological games in space and time: the distribution and abundance of Antarctic krill and penguins

The distribution and abundance of organisms are affected by behaviors, such as habitat selection, foraging, and reproduction. These behaviors are driven by interactions within and between species, environmental conditions, and the biology of the species involved. Although extensive theoretical work has explored predator–prey dynamics, these models have not considered the impact of behavioral plasticity and life-history trade-offs on predicted patterns. We apply a modeling method that allows the consideration of a spatial, dynamic ecological game between predators and prey using a life-history perspective. As an illustrative example, we model the habitat selection of Antarctic krill and penguins during the time when penguins are land-based for reproduction. Although environmental conditions and the life-history constraints of each species have both direct and indirect effects on both species, the penguin’s foraging rule (whether food-maximizing or time-minimizing) has the greatest effect on the qualitative distribution pattern of both species. Size-dependent diel vertical migration of krill also strongly affects penguin foraging patterns. This model generates suggestions for future research and qualitative predictions that can be tested in the field. The application of this method to a specific problem also demonstrates its ability to increase our understanding of important ecological interactions in general.