Wild boar habitat selection in south-central Sweden's forested habitats : effects of season and time

Sammanfattning: How wild boar utilize space, interact, and affect its surroundings is critical for understanding their ecology. Wild boar populations have increased rapidly in Sweden and continue to expand its distributional range further north. Little is known about how wild boar utilize the forest habitat in the boreal and hemi-boreal zone and increased knowledge is needed to ensure informed management decisions. Thus, this study aims to investigate wild boar habitat selection in forest habitats, depending on season and time of day. The study was conducted in six different study areas in south-central Sweden representing contrasting environmental conditions. Locations from 76 wild boar fitted with GPS-collars between 2018 - 2022 provided data on wild boar movements between habitats. Habitats were analysed using Generalized Linear Mixed Models, controlling for several different environmental covariates. Mature deciduous forests and young regenerated forests (approx. 3 - 7 m high) were the most preferred forest habitats by wild boar. Seasonal variation in habitat selection could primarily be attributed to natural variation of the respective habitat’s ability to provide food and shelter. Differences in selection during daytime or night-time revealed that young forests were significantly more preferred by wild boar during daytime. During the night wild boar left young forests presumably to search for food in non-forested habitats as preference for such habitats increased. The effect of the environmental variables: tree height, soil moisture, slope, ruggedness and slope aspect, was unclear. However, when the environmental variables were included the general patterns of habitat selection remained, indicating that the habitat as a whole is the main determinant for selection.