Population recovery of a common vole population (Microtus arvalis) after population collapse

BACKGROUND Population collapses in small mammals occur naturally after natural disasters and during multi‐annual population fluctuations as well as after man‐made intervention such as rodent management action. Although there has been extensive previous work on patterns and mechanisms of population fluctuations and cyclicity, there is only little known about population recovery after collapse. In Europe, the common vole (Microtus arvalis) is the major pest species in agriculture which damages crops, competes with livestock and can pose a health risk to people. In this study, we investigated population recovery, recovery mechanism and recovery time of common vole populations after artificially inducing a collapse through rodenticide application. RESULTS The rodenticide treatment reduced abundance only in spring (by about 90%) but not in summer. Demographic data (age, sex‐ratio, breeding activity) suggest that it was mostly immigration and not reproduction that led to population recovery after collapse. CONCLUSIONS The findings indicate that rodenticide treatment should be conducted in spring before the main reproductive season starts. The treatment effect was transient and lasted for about 3 months before immigration offset the initial reduction in population abundance. This indicates that immigration patterns should be considered by managing vole populations at an appropriate spatial scale and frequency to prevent rapid repopulation.