Phytoplankton, and the zooplankton that graze upon them, play a crucial role in the dynamics observed at higher levels of the aquatic ecosystem. There is a vast literature on differential equation models of plankton dynamics, and a recent trend in ecological models has considered plasticity in parameters and adaptation. In this talk, we interpret plasticity as prey switching, that is, predator’s adaptive change of diet in response to the abundance of prey. We first analyse a model constructed for one predator feeding on two different types of prey and inspired by plankton observations. This model has a discontinuity between two vector fields. We then discuss two different smooth formulations of the model and compare model predictions with data on freshwater plankton collected from Lake Constance on the German-Swiss-Austrian border. Finally, we discuss a 1 fast-3 slow system for one predator feeding adaptively on two different prey types and inspired by the first model.
Speaker(s): Sofia Piltz (University of Michigan)