Positive effects of set-asides on European hare (Lepus europaeus) populations: Leverets benefit from an enhanced survival rate

Since agricultural intensification started in the early 1900s, farmland biodiversity in Europe has decreased. Non-farmed features are of high importance for the promotion of plant and animal species including the European hare (Lepus europaeus). As an immediate cause of the decline in European hare abundances, a reduction in reproductive success has been proposed. Female fertility is not impaired and leveret mortality is inherently high in this lagomorph species. However, hunting bags suggest that leveret mortality has increased in recent decades. We studied the effect of set-asides on population trends of hunted European hares by analysing data of spotlight counts and of hunting bags in arable landscapes in Lower Austria during six years. We found no interannual and interareal differences in reproductive output of adult females. Accordingly, female reproductive output had no effect on population growth of the hares. Leveret survival rate was higher in the study sites with a high proportion of set-asides (9 and 13%) than in the sites with a lower proportion of set-asides (3 and 5%). We recorded a positive effect of leveret survival rate on population growth and next year's spring density. Moreover, the proportion of set-asides positively affected spring density, population growth, hunting bag, leveret survival rate and number of subadults in autumn. Hence, set-asides contribute to the survival of leverets and, correspondingly, population growth and spring density. Accordingly, set-asides are a highly important habitat measure and an evidence-based conservation tool for the promotion of this species in arable landscapes. •European hare's female reproductive output has no effect on population growth.•Leveret survival rate has an effect on population growth and spring density.•Set-asides affect spring density, population growth, and leveret survival rate.•Set-asides are an important conservation tool for the promotion of this species.