The problem of synchronization of metacommunities is investigated in this article with reference to a rather general model composed of a chaotic environmental compartment driving a biological compartment. Synchronization in the absence of dispersal (i.e., the so-called Moran effect) is first discussed and shown to occur only when there is no  biochaos. In other words, if the biological compartment is reinforcing environmental chaos,  dispersal must be strictly above a specified threshold in order to synchronize population  dynamics. Moreover, this threshold can be easily determined from the model by computing a special Lyapunov exponent. The application to prey-predator metacommunities points  out the influence of frequency and coherence of the environmental noise on  synchronization and agrees with all experimental studies performed on the subject.