Friday, August 10, 2007 - 8:00 AMCOS 157-1: Meta-population model of predator-prey mussel bed dynamics
Lucinda D. Robledo and Dr. Robert A. Desharnais. California State University, Los Angeles
A relatively recent theoretical development in ecology is the study of ecological dynamics on multiple scales. The present study extends the one-bed population-scale model consisting of three coupled ordinary differential equations (ODE) for predator-prey mussel bed dynamics of intertidal mussel beds to a regional scale “metapopulation” of mussel beds linked by predation. The initial model considered consists of two mussel beds linked by a common predator population. The dynamics of the two-bed model were studied for varying levels of predation. For very low levels of predation both mussel beds had a high biomass and for high levels of predation both mussel beds had a low biomass. For intermediate values of predation there are multiple stable equilbria and the final state of the metapopulation will depend on initial conditions. The two-bed metapopulation model was extended to any arbitrary number of metapopulation models. The topological arrangement must be considered when modeling metapopulations of several mussel populations. Two types are being studied: the harbor model and the coastal model. The harbor model consists of n mussel beds which share a common pool of predators that move randomly among the mussel beds. The coastal model consists of a linear array of n mussel beds which act as “stepping stones;” predators can move to and from adjacent mussel beds only. Preliminary results on these complex metapopulation models will be presented. Using a multi-scale spatial model will provide a better understanding the ecology of predator-prey dynamics at a regional scale and may suggest field experiments.