Population Variability in Space and Time: The Dynamics of Synchronous Population Fluctuations

Empirical studies have shown that animal populations from a wide array of taxa exhibit spatial patterns of correlation in fluctuating abundance. In the search for explanations for this phenomenon it has been proposed that subpopulation interactions in the form of spatial dispersal, or variability in external factors, such as weather, would be the crucial driving forces responsible for spatial synchrony. Nevertheless, dispersal and external factors have been shown to produce different patterns of synchrony. We show here that observed patterns in synchronous dynamics can be reproduced by using a spatially linked population model. Further, we analyse how local and global environmental stochasticity and dispersal influence the pattern of spatial synchrony. We contrast our theoretical results with data on long-term dynamics of North American game animals and emphasize that the data and our spatial population dynamics models are compatible.