Dispersal and stability in metapopulations

What are the stability consequences of density-independent dispersal betwee n locally distinct populations? Can such dispersal stabilize population dyn amics or is it more likely to be a destabilizing influence? If so, what are the conditions required for dispersal-induced instability? We address thes e questions firstly by briefly reviewing the current literature, where it h as been established that equilibrium stability in single-species models is not affected by dispersal. We then present a general model for two-species interaction, and establish, using analytic techniques, that density-indepen dent movement between populations is never stabilizing; it may, however, de stabilize. We conclude that in discrete-time models, dispersal may be desta bilitizing if the following three criteria are satisfied: (1) there is more than one variable (species or age class) in the system, (2) the movement f ractions of the two variables (species or age classes) are very different, and (3) the interaction between the variables (species or age classes) is s emi-antagonistic (e.g, a predator-prey system).