Spatial synchrony is a widespread phenomenon occurring in many taxa. Identifying patterns and mechanisms of synchrony is fundamental to understanding factors that influence large-scale population dynamics, with broad implications for conserving ecological systems. We present an opportunistic approach to large-scale empirical synchrony analysis. We combine time series and genetic data provided by hunters and trappers, government agencies, and disparate research efforts conducted over varying time and geographic scales, to evaluate one commonly proposed mechanism—dispersal—for the legendary synchrony of snowshoe hare cycles across much of the species’ range. Snowshoe hare time series and/or genetic data were compiled from over 50 sources distributed across 11 of the 13 Canadian provinces/territories and 16 of the 26 U.S. states where snowshoe hares occur. We used simulation modeling and spatial statistics to quantify range-wide patterns of snowshoe hare synchrony. A similar analysis identified spatial genetic structure and potential barriers to snowshoe hare gene flow among sampled areas. We measured correspondence between snowshoe hare gene flow and synchrony patterns, to provide insight on the likelihood of hare dispersal as a synchronizing mechanism.

Results/Conclusions

Based on results of simulation modeling, we developed minimum data quality guidelines (regarding time series length, missing data, and sampling method) for combining time series data opportunistically collected from various sources in a single analysis of synchrony. These guidelines were used to inform our quantification of range-wide hare synchrony patterns. Genetic analyses revealed that populations in parts of the snowshoe hares’ southern range are more genetically differentiated than are more northern hare populations. Breaks in gene flow among hare populations generally corresponded with large-scale natural breaks in forested hare habitats. We present findings on correspondence between hare dispersal (measured by gene flow) and synchrony dynamics in snowshoe hares.