Proposed mechanism for increased reproductive potential of wild boars under hunting pressure

Abstract

Throughout Europe and Asia, populations of wild boars (Sus scrofa) demonstrate a steady increase in recent decades. This results in increased conflicts between wild boars and humans, intensifying economic costs like epidemics to livestock and humans, damages to gardens in urban areas and agricultural crops. Culling wild boars is the most widespread management tool throughout the world in attempts to minimize these conflicts. Yet, studies demonstrate that populations of wild boars exposed to high hunting pressure have shorter generation times associated with higher reproduction rates. The mechanisms of this phenomenon have not been examined to date, thus favoring the culling practice to go undisturbed. Our research goal is to evaluate the effects of hunting on wild boars population structure, dynamics, behavior and reproduction in four different land uses: urban with and without hunting, non urban (agriculture and nature reserves) with and without hunting. To do so, we are using motion triggered cameras (monitoring vigilance behavior), giving up densities (GUDs) experiments and analysis of stress and reproduction hormones levels in hair. Our results, so far, show striking behavioral differences between boars in urban and open spaces regardless of hunting pressure based on GUD studies and analysis of videos. These experiments suggest a lower perceived risk of humans in urban areas, where boars consumed all the food provided in the GUD studies, and thus putatively affecting the reproduction potential of boars in human vicinity. Furthermore, we found that hunting in non-urbanized lands decreases the dispersal of the yearlings. These herds also showed a high level of vigilance compared to the urban herds. We suggest that the combination of vigilance and low dispersal rates may lead to increased reproductive potential.