Impacts of zoning and landscape structure on the relative abundance of wild boar assessed through a Bayesian N-mixture model

Abstract

Increasing human-wild boar interactions have led to damage to agricultural crops, traffic collisions and disease transmissions. Dividing natural areas in zones with differential hunting pressure is one of the currently adopted management strategies. However, the effectiveness of this approach is under debate. Hence, there is a need to better understand how to mitigate negative human-wild boar interactions effectively.Camera traps are cost-efficient, and non-invasive tools to monitor animal populations. N-mixture models can reliably estimate spatial variation in relative abundances when animals are imperfectly detected and/or cannot be individually identified. Thus, they are useful tools to infer the impacts of several factors on the land-use intensity of wild boar, based on camera trap data. In a nature area in central Belgium, we compare "summer" (April-September) land-use intensity of wild boar from 2018 until 2021 between three zones: a hunting free core zone, a winter hunting zone where hunting only takes place between November and March, and a year-round hunting zone. The latter is also close to the forest edge, agricultural crops and settlements. We compare spatial abundance models that capture these zone effects, or attractive effects of croplands, repulsive effects of hunting and repulsive effects of non-lethal human disturbances.We reveal between zone differences in wild boar land-use intensities across all summers. Additionally, we find that non-lethal human disturbance and croplands also explain variation in wild boar land-use intensity, but do not find negative associations with hunting locations. Our results suggest that the effects of zoning on wild boar land-use patterns are relevant in medium-sized natural areas. Moreover, we identify the need to install additional cameras outside of the managed area in order to assess the impacts of hunting in combination with non-lethal human activities on wild boar to mitigate negative human-wild boar interactions in the future.