Behavioural responses to ecological stressors: sex-specific shifts in wild boar activity over the Mediterranean summer

Ecological perturbations of the Anthropocene are increasingly affecting animal populations. The interplay among rising temperatures, landscape features, human activities, and predators can alter mammal behaviour, yet these factors are rarely examined simultaneously. Understanding how mammals respond to multiple stressors is key to improving knowledge on their behavioural flexibility and to predicting shifts in interspecific and human–wildlife interactions. We investigated the effects of temperature, habitat features, human activity, and predator activity on daily activity levels and nocturnality of a widespread ungulate, the wild boar Sus scrofa. We conducted population-level and sex-specific-level analyses of camera trapping data collected in eight Mediterranean protected areas over summers 2021-2024 (19 306 camera-days; 208 sites). While effects of temperature on daily activity level were not supported, wild boar increased nocturnality in warmer days, indicating a temporal redistribution of activity rather than an overall decline to cope with heat. Activity increased near persistent water sources and, for males, this relationship was stronger on hotter days. Activity also increased near agricultural lands, which were used at night as open habitats. Wild boar activity decreased in sites with higher human visitation rates and exhibited general nocturnal/crepuscular activity patterns, suggesting spatio-temporal avoidance of humans. However, fine-scale temporal adjustments emerged: males and females without offspring showed more nocturnal and crepuscular activity patterns, whereas females with offspring showed greater diurnal activity, suggesting that these individuals prioritized avoidance of nocturnal predators (i.e., the wolf Canis lupus). Results suggest that wild boar cope with Mediterranean summer through flexible, sex-specific temporal adjustments shaped by thermal, ecological, and risk-related drivers. Our study emphasises the importance of considering multiple stressors when assessing behavioural responses to environmental variation.