Population oscillations of boreal rodents: regulation by mustelid predators leads to chaos.

摘要: THE four-year cycle of microtine rodents in boreal and arctic regions was first described 1924 (ref. 1). Competing hypotheses on the mechanisms underlying small mammal have been extensively tested2–5, but so far sustained rodent oscillations are unexplained. Here we use two mutually supportive approaches to investigate this question. First, building studies interaction between their mustelid predators6–9, construct a predator–prey model with seasonality. Second, new technique nonlinear analysis10,11 examine empirical time-series data, compare them dynamics. The parameterized field data predicts dynamics that closely resemble observed populations. Both predicted chaotic, albeit statistically significant periodic component. Our results suggest multiannual populations Fennoscandia due delayed density dependence imposed by predators, chaotic.