Effect of temporal variation in reproduction on models of population viability: a case study for remnant arctic fox (Alopex lagopus) populations in Scandinavia Original Research Article

Despite more than 69 years of protection populations of arctic fox (Alopex lagopus) in Scandinavia has not recovered their former numbers or distribution following over-hunting at the turn of the century. We aimed to evaluate the possible fate of arctic fox populations using discrete-time models including both demographic and environmental variability. Because the reproduction of arctic fox in Scandinavia is dependent on the abundance of small rodents, which is cyclic, we included the temporal variability of reproductive performances in our viability analysis based on time series available for three Scandinavian populations. Whatever the modelling of the reproductive performances and the range of adult survival rates considered, the risks of extinction were high. They were very sensitive to adult survival rates and variability in reproductive performances. Populations with the longest duration between two successful reproductions were at the greatest risks of extinction. The time elapsed between two successful reproductions may depend on failure to respond to rodent peaks. The cyclicity of food availability for arctic fox may have been the main selective force for their large litter size, but may also be the cause of a fine-tuned, and fragile dynamic system.