The curse of zombie dispersal in discrete-time models of spatial population dynamics

In many metapopulation and metacommunity models, individuals disperse between discrete habitat patches. When those models treat time as a discrete variable, the formulation of the dispersal term must be handled with care. A commonly made mistake is to model dispersal with terms identical to those found in continuous-time models. Such terms can inadvertently resurrect dead individuals, effectively creating "zombie dispersers." Zombie dispersal, in turn, can have dramatic, but spurious, effects on model dynamics. In this manuscript, we illustrate the misleading effects generated by zombie dispersal in a published model used to investigate how dispersal mediates synchrony in population dynamics.