Factors affecting hare-lynx dynamics in the classic time series of the Hudson Bay Company, Canada

The 10 yr hare-lynx (Lepus americanus-Lynx canadensis) cycles in boreal forest of North America have been well known for > 100 yr, but the underlying mechanism is still not fully understood. Prey-predator interactions are generally thought to be the major causative factor for the cycle. The effect of climate on the hare-lynx cycle has been largely ignored. By using partial cross correlation and stepwise multiple regression methods, we re-analyzed the Hudson Bay Company's well known hare-lynx time series (1847-1903), to evaluate effects of intrinsic self-regulation, prey-predator interactions and El Nino/Southern Oscillation (ENSO) on hare-lynx dynamics. Our results clearly indicate that the widely cited classic hare-lynx dynamic is mostly explained by intrinsic self-regulation factors, instead of by prey-predator interaction; ENSO has small effects on rates of increase in hare and lynx populations.