Fox Vulpes vulpes population trends in Western Europe during and after the eradication of rabies

Over several decades, Western Europe experienced an outbreak of sylvatic rabies, eliminated through an EU programme involving large-scale red fox vaccination campaigns. While much work has been done on the dynamics of the virus and on the efficiency of vaccination campaigns, very little attention has been paid to the impact on the large-scale dynamics of the fox population. As Western Europe has now been free of rabies for about 15-20 years, the aims of this review are to characterise the impact of rabies during the outbreak itself and to increase understanding of how fox populations evolved thereafter. The rabies-free populations in the UK are also integrated as a comparative control. Trends in fox populations are based on a review of available data, mainly hunting statistics and a few other methods. The benefits and biases of these methods are also discussed. During the rabies epizootic, fox populations experienced a significant decline and stabilised at lower densities than observed in the past. A demographic explosion followed the vaccination campaigns, and fox populations became larger than had been observed before the epizootic. Rabies vaccination was not the direct cause of this demographic explosion, as rabies-free areas experienced it also. The causes are more to be sought in environmental modifications induced by humans. This demographic explosion was followed by the emergence of urban fox populations throughout Europe. Moreover, the new higher densities favoured the outbreak of other diseases, though their impact was more limited. Around the 2000s, rural fox populations appeared to reach densities close to carrying capacity and populations stabilised. However, subsequently, with some exceptions, Western European fox populations seem to be experiencing a decline. The ecological consequences of these changes in fox population density may reach the many prey species and competitors of the red fox.