Spatial synchrony is defined by correlated fluctuations in population abundance at different locations, the strength of which typically declines with increasing distance between census locations. Standard approaches for assessing synchrony effectively assume isotropy in space and uniformity across timescales of analysis, but it is now well known that spatial variability and timescale structure in population dynamics are common features. We tested for spatial and timescale structure in the patterns of synchrony of freshwater plankton in Kentucky Lake, Kentucky USA. We also evaluated whether different mechanisms may drive synchrony and its spatial structure on different timescales. Using wavelet techniques and matrix regression, we analyzed biomass of phytoplankton and abundances of nine zooplankton species at 16 spatial locations over a 26 year span (1990-2015); we compared the effects of drivers including dispersal, environmental synchrony, species interactions, density dependence and distances between populations on population dynamics and its spatial variation.
We found that all zooplankton and phytoplankton exhibited synchrony at multiple timescales, and that timescale structure was evident. Timescale structure in mechanisms of synchrony was revealed primarily through networks of relationships between taxa, which differed by timescale. We found a high degree of interspecific variability in geographic structures of synchrony and their causes - all mechanisms considered except geographic distance were supported for explaining geographic structure in synchrony for at least one species. Geographic structure in synchrony and the relative importance of its mechanisms depended on timescale for over half the taxa tested. Overall, our results show substantial and complex variation in structures of synchrony along three axes: spatially, according to timescale, and by taxon. Elucidating broad conceptual patterns across taxa may be difficult due to variability in life history, environmental responsiveness, and other aspects of physiology and ecology, but details in structures of synchrony such as we have revealed may also aid inferences about population dynamics.